* [PATCH v8 32/37] virtio_balloon: disable reporting zeroed optimization for confidential guests
From: Michael S. Tsirkin @ 2026-05-20 22:23 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
In confidential computing environments (TDX, SEV-SNP), the host
is untrusted and may lie about zeroing reported pages. Clear
DEVICE_INIT_REPORTED in validate() so the guest does not skip
re-zeroing based on hints from an untrusted device.
Note: currently REPORTING remains enabled and
VIRTIO_F_ACCESS_PLATFORM is cleared in CC environments.
This is known to leak free page physical addresses to the
host. Whether that, or ballooning in general, is a security
concern in CC is up to the user. This patch only disables
our new zeroed-page hints where the host is untrusted.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
drivers/virtio/virtio_balloon.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index e3afa6f32ba5..bf1172ad5419 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -19,6 +19,7 @@
#include <linux/wait.h>
#include <linux/mm.h>
#include <linux/page_reporting.h>
+#include <linux/cc_platform.h>
/*
* Balloon device works in 4K page units. So each page is pointed to by
@@ -1193,6 +1194,8 @@ static int virtballoon_validate(struct virtio_device *vdev)
!want_init_on_free())
__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
+ if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
+ __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
/*
* Balloon submits 1-2 sg entries max per buffer, virtqueue
* sizes are 128+. Disable indirect descriptors to avoid
--
MST
^ permalink raw reply related
* [PATCH v8 31/37] virtio_balloon: skip zeroing for host-zeroed reported pages
From: Michael S. Tsirkin @ 2026-05-20 22:23 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Implement VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED (per virtio spec
proposal): when negotiated, the device initializes reported pages
(zeros, or poison_val if PAGE_POISON).
Check per-page used length returned by the device to determine
which reported pages were zeroed. If used_len matches the page
size, the device successfully initialized the page (e.g. via
MADV_DONTNEED), and we set the corresponding zeroed_bitmap bit.
Gate host_zeroes_pages on the feature bit and page content:
when PAGE_POISON is negotiated with non-zero poison_val, the
device fills with poison not zeros, so pages are not zeroed.
Clear the feature in validate() if REPORTING is not present
or if PAGE_POISON is active with non-zero poison_val.
See the virtio spec change:
https://github.com/oasis-tcs/virtio-spec/issues/244
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
drivers/virtio/virtio_balloon.c | 22 ++++++++++++++++++++--
include/uapi/linux/virtio_balloon.h | 1 +
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 1fa1c7fa285f..e3afa6f32ba5 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -207,6 +207,8 @@ static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_i
struct virtqueue *vq = vb->reporting_vq;
unsigned int i, err = 0;
+ bitmap_zero(pr_dev_info->zeroed_bitmap, nents);
+
/* We should always be able to add these buffers to an empty queue. */
for (i = 0; i < nents; i++) {
struct scatterlist one;
@@ -226,10 +228,14 @@ static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_i
/* When host has read buffer, this completes via balloon_ack */
for (i = 0; i < nents; i++) {
- unsigned int unused;
+ struct scatterlist *entry;
+ unsigned int used_len;
wait_event(vb->acked,
- virtqueue_get_buf(vq, &unused));
+ (entry = virtqueue_get_buf(vq, &used_len)));
+ if (used_len == entry->length)
+ set_bit(entry - sg,
+ pr_dev_info->zeroed_bitmap);
}
}
@@ -1051,6 +1057,9 @@ static int virtballoon_probe(struct virtio_device *vdev)
#endif
vb->pr_dev_info.capacity = capacity;
+ vb->pr_dev_info.host_zeroes_pages =
+ virtio_has_feature(vdev,
+ VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
err = page_reporting_register(&vb->pr_dev_info);
if (err)
goto out_unregister_oom;
@@ -1176,6 +1185,14 @@ static int virtballoon_validate(struct virtio_device *vdev)
else if (!virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON))
__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_REPORTING);
+ if (!virtio_has_feature(vdev, VIRTIO_BALLOON_F_REPORTING))
+ __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
+
+ /* Device fills with poison_val, not zeros; disable zeroed hint */
+ if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON) &&
+ !want_init_on_free())
+ __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED);
+
/*
* Balloon submits 1-2 sg entries max per buffer, virtqueue
* sizes are 128+. Disable indirect descriptors to avoid
@@ -1194,6 +1211,7 @@ static unsigned int features[] = {
VIRTIO_BALLOON_F_FREE_PAGE_HINT,
VIRTIO_BALLOON_F_PAGE_POISON,
VIRTIO_BALLOON_F_REPORTING,
+ VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED,
};
static struct virtio_driver virtio_balloon_driver = {
diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index ee35a372805d..13074631f300 100644
--- a/include/uapi/linux/virtio_balloon.h
+++ b/include/uapi/linux/virtio_balloon.h
@@ -37,6 +37,7 @@
#define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */
#define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */
#define VIRTIO_BALLOON_F_REPORTING 5 /* Page reporting virtqueue */
+#define VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED 6 /* Device initializes reported pages */
/* Size of a PFN in the balloon interface. */
#define VIRTIO_BALLOON_PFN_SHIFT 12
--
MST
^ permalink raw reply related
* [PATCH v8 30/37] mm: page_alloc: propagate PG_zeroed in split_large_buddy
From: Michael S. Tsirkin @ 2026-05-20 22:23 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
When splitting a large buddy page, propagate the PG_zeroed flag
to each sub-page before freeing it. __free_pages_prepare clears
all flags (including PG_zeroed), so the flag must be re-set on
each fragment after the split. This ensures that the buddy merge
logic can see PG_zeroed on pages that were part of a larger
zeroed block.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
mm/page_alloc.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 72e52f049cf0..702fa2ced1e1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1524,6 +1524,7 @@ static void split_large_buddy(struct zone *zone, struct page *page,
{
unsigned long end = pfn + (1 << order);
bool reported = PageReported(page);
+ bool zeroed = PageZeroed(page);
VM_WARN_ON_ONCE(!IS_ALIGNED(pfn, 1 << order));
/* Caller removed page from freelist, buddy info cleared! */
@@ -1537,6 +1538,8 @@ static void split_large_buddy(struct zone *zone, struct page *page,
if (reported)
__SetPageReported(page);
+ if (zeroed)
+ __SetPageZeroed(page);
__free_one_page(page, pfn, zone, order, mt, fpi);
pfn += 1 << order;
if (pfn == end)
--
MST
^ permalink raw reply related
* [PATCH v8 29/37] mm: page_reporting: add flush parameter with page budget
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Add a write-only module parameter 'flush' that triggers immediate
page reporting. The value specifies a page budget: at least
this many pages (at page_reporting_order) will be reported,
or all unreported pages if fewer remain. The actual number
reported may exceed the budget since each reporting pass
processes a full cycle across all zones.
This is helpful when there is a lot of memory freed quickly,
and a single cycle may not process all free pages due to
internal budget limits.
echo 512 > /sys/module/page_reporting/parameters/flush
Note: the set callback runs under kernel param_lock,
so writing this parameter blocks other built-in parameter
writes until the flush loop completes. This is acceptable
for a privileged debug/test parameter.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
mm/page_reporting.c | 54 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 54 insertions(+)
diff --git a/mm/page_reporting.c b/mm/page_reporting.c
index 691a9e66aa5b..8b278a494ea5 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -358,6 +358,60 @@ static void page_reporting_process(struct work_struct *work)
static DEFINE_MUTEX(page_reporting_mutex);
DEFINE_STATIC_KEY_FALSE(page_reporting_enabled);
+static int page_reporting_flush_set(const char *val,
+ const struct kernel_param *kp)
+{
+ struct page_reporting_dev_info *prdev;
+ unsigned int budget;
+ int err;
+
+ err = kstrtouint(val, 0, &budget);
+ if (err)
+ return err;
+ if (!budget)
+ return 0;
+
+ mutex_lock(&page_reporting_mutex);
+ prdev = rcu_dereference_protected(pr_dev_info,
+ lockdep_is_held(&page_reporting_mutex));
+ if (prdev) {
+ unsigned int reported;
+ bool interrupted = false;
+
+ for (reported = 0; reported < budget;
+ reported += min(prdev->capacity, budget - reported)) {
+ /*
+ * First flush completes any previously scheduled
+ * reporting work. Then request a new reporting
+ * cycle and flush again to execute it.
+ */
+ flush_delayed_work(&prdev->work);
+ __page_reporting_request(prdev);
+ flush_delayed_work(&prdev->work);
+ if (atomic_read(&prdev->state) == PAGE_REPORTING_IDLE)
+ break;
+ if (signal_pending(current)) {
+ interrupted = true;
+ break;
+ }
+ }
+ if (interrupted) {
+ mutex_unlock(&page_reporting_mutex);
+ return -EINTR;
+ }
+ }
+ mutex_unlock(&page_reporting_mutex);
+ return 0;
+}
+
+static const struct kernel_param_ops flush_ops = {
+ .set = page_reporting_flush_set,
+ .get = param_get_uint,
+};
+static unsigned int page_reporting_flush;
+module_param_cb(flush, &flush_ops, &page_reporting_flush, 0200);
+MODULE_PARM_DESC(flush, "Report at least N pages at page_reporting_order, or until all reported");
+
int page_reporting_register(struct page_reporting_dev_info *prdev)
{
int err = 0;
--
MST
^ permalink raw reply related
* [PATCH v8 28/37] virtio_balloon: disable indirect descriptors
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Balloon submits at most 1-2 scatter-gather entries per buffer and
virtqueue sizes are 128+, so indirect descriptors are unnecessary.
Disabling them avoids a GFP_KERNEL allocation inside
virtqueue_add_sgs when VIRTIO_RING_F_INDIRECT_DESC is negotiated.
This allocation could trigger OOM reclaim while balloon_lock is
held, leading to a deadlock: OOM notifier -> leak_balloon ->
balloon_lock.
With single-buffer submissions (previous patch) and no indirect
descriptors, virtqueue_add never allocates memory.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
drivers/virtio/virtio_balloon.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 53b4a3984e7d..1fa1c7fa285f 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -7,6 +7,7 @@
*/
#include <linux/virtio.h>
+#include <uapi/linux/virtio_ring.h>
#include <linux/virtio_balloon.h>
#include <linux/swap.h>
#include <linux/workqueue.h>
@@ -1175,6 +1176,13 @@ static int virtballoon_validate(struct virtio_device *vdev)
else if (!virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON))
__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_REPORTING);
+ /*
+ * Balloon submits 1-2 sg entries max per buffer, virtqueue
+ * sizes are 128+. Disable indirect descriptors to avoid
+ * GFP_KERNEL allocation in virtqueue_add under balloon_lock,
+ * which could deadlock via OOM -> oom_notify -> leak_balloon.
+ */
+ __virtio_clear_bit(vdev, VIRTIO_RING_F_INDIRECT_DESC);
__virtio_clear_bit(vdev, VIRTIO_F_ACCESS_PLATFORM);
return 0;
}
--
MST
^ permalink raw reply related
* [PATCH v8 27/37] virtio_balloon: submit reported pages as individual buffers
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Submit each reported page as a separate virtqueue buffer instead
of one buffer with an sg list of all pages. This avoids indirect
descriptor allocation (kmalloc in the reporting path) and gives
per-page used length feedback from the device.
On error, the already-queued pages are kicked and drained
before the error is returned. The caller (page_reporting_drain)
then marks the batch as unreported, which is conservative
but correct.
Note: if the virtqueue is broken, wait_event on
virtqueue_get_buf hangs. This is a pre-existing issue:
the old single-buffer code had the same hang. EVENT_IDX
is not a concern: callbacks were never disabled, so the
virtqueue manages used_event automatically.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
drivers/virtio/virtio_balloon.c | 40 +++++++++++++++++++++------------
1 file changed, 26 insertions(+), 14 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 6a1a610c2cb1..53b4a3984e7d 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -187,7 +187,9 @@ static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq)
sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns);
- /* We should always be able to add one buffer to an empty queue. */
+ /* We made sure the vq is large enough so we should always
+ * be able to add one buffer to an empty queue.
+ */
virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL);
virtqueue_kick(vq);
@@ -202,25 +204,35 @@ static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_i
struct virtio_balloon *vb =
container_of(pr_dev_info, struct virtio_balloon, pr_dev_info);
struct virtqueue *vq = vb->reporting_vq;
- unsigned int unused, err;
+ unsigned int i, err = 0;
/* We should always be able to add these buffers to an empty queue. */
- err = virtqueue_add_inbuf(vq, sg, nents, vb, GFP_NOWAIT);
+ for (i = 0; i < nents; i++) {
+ struct scatterlist one;
- /*
- * In the extremely unlikely case that something has occurred and we
- * are able to trigger an error we will simply display a warning
- * and exit without actually processing the pages.
- */
- if (WARN_ON_ONCE(err))
- return err;
+ sg_init_table(&one, 1);
+ sg_set_page(&one, sg_page(&sg[i]), sg[i].length,
+ sg[i].offset);
+ err = virtqueue_add_inbuf(vq, &one, 1, &sg[i], GFP_NOWAIT);
+ if (WARN_ON_ONCE(err)) {
+ nents = i;
+ break;
+ }
+ }
- virtqueue_kick(vq);
+ if (nents) {
+ virtqueue_kick(vq);
- /* When host has read buffer, this completes via balloon_ack */
- wait_event(vb->acked, virtqueue_get_buf(vq, &unused));
+ /* When host has read buffer, this completes via balloon_ack */
+ for (i = 0; i < nents; i++) {
+ unsigned int unused;
- return 0;
+ wait_event(vb->acked,
+ virtqueue_get_buf(vq, &unused));
+ }
+ }
+
+ return err;
}
static void set_page_pfns(struct virtio_balloon *vb,
--
MST
^ permalink raw reply related
* [PATCH v8 26/37] mm: page_alloc: preserve PG_zeroed in page_del_and_expand
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Propagate PG_zeroed through buddy splits in page_del_and_expand()
and try_to_claim_block(). When a zeroed high-order page is split
to satisfy a smaller allocation, the sub-pages placed back on the
free lists keep PG_zeroed.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
mm/page_alloc.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ff614e422eec..72e52f049cf0 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1715,7 +1715,8 @@ struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
* -- nyc
*/
static inline unsigned int expand(struct zone *zone, struct page *page, int low,
- int high, int migratetype, bool reported)
+ int high, int migratetype, bool reported,
+ bool zeroed)
{
unsigned int size = 1 << high;
unsigned int nr_added = 0;
@@ -1746,6 +1747,8 @@ static inline unsigned int expand(struct zone *zone, struct page *page, int low,
*/
if (reported)
__SetPageReported(&page[size]);
+ if (zeroed)
+ __SetPageZeroed(&page[size]);
}
return nr_added;
@@ -1757,10 +1760,12 @@ static __always_inline void page_del_and_expand(struct zone *zone,
{
int nr_pages = 1 << high;
bool was_reported = page_reported(page);
+ bool was_zeroed = PageZeroed(page);
__del_page_from_free_list(page, zone, high, migratetype);
- nr_pages -= expand(zone, page, low, high, migratetype, was_reported);
+ nr_pages -= expand(zone, page, low, high, migratetype, was_reported,
+ was_zeroed);
account_freepages(zone, -nr_pages, migratetype);
}
@@ -2356,11 +2361,12 @@ try_to_claim_block(struct zone *zone, struct page *page,
if (current_order >= pageblock_order) {
unsigned int nr_added;
bool was_reported = page_reported(page);
+ bool was_zeroed = PageZeroed(page);
del_page_from_free_list(page, zone, current_order, block_type);
change_pageblock_range(page, current_order, start_type);
nr_added = expand(zone, page, order, current_order, start_type,
- was_reported);
+ was_reported, was_zeroed);
account_freepages(zone, nr_added, start_type);
return page;
}
--
MST
^ permalink raw reply related
* [PATCH v8 25/37] mm: page_alloc: clear PG_zeroed on buddy merge if not both zero
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
When two buddy pages merge in __free_one_page(), preserve
PG_zeroed on the merged page only if both buddies have the
flag set. Otherwise clear it.
The merged page would inherit PG_zeroed, and a later __GFP_ZERO
allocation would skip zeroing stale data in the non-zero half.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
include/linux/page-flags.h | 1 +
mm/page_alloc.c | 15 ++++++++++++++-
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 4ee64134acc3..ff0b192b38e5 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -680,6 +680,7 @@ FOLIO_FLAG_FALSE(idle)
* uses this to skip redundant zeroing in post_alloc_hook().
*/
__PAGEFLAG(Zeroed, zeroed, PF_NO_COMPOUND)
+CLEARPAGEFLAG(Zeroed, zeroed, PF_NO_COMPOUND)
#define __PG_ZEROED (1UL << PG_zeroed)
/*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4cb7e779a6c5..ff614e422eec 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -940,10 +940,14 @@ static inline void __free_one_page(struct page *page,
unsigned long buddy_pfn = 0;
unsigned long combined_pfn;
struct page *buddy;
+ bool buddy_zeroed;
+ bool page_zeroed;
bool to_tail;
VM_BUG_ON(!zone_is_initialized(zone));
- VM_BUG_ON_PAGE(page->flags.f & PAGE_FLAGS_CHECK_AT_PREP, page);
+ /* PG_zeroed (aliased to PG_private) is valid on free-list pages */
+ VM_BUG_ON_PAGE(page->flags.f &
+ (PAGE_FLAGS_CHECK_AT_PREP & ~__PG_ZEROED), page);
VM_BUG_ON(migratetype == -1);
VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
@@ -978,6 +982,8 @@ static inline void __free_one_page(struct page *page,
goto done_merging;
}
+ buddy_zeroed = PageZeroed(buddy);
+
/*
* Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
* merge with it and move up one order.
@@ -996,10 +1002,17 @@ static inline void __free_one_page(struct page *page,
change_pageblock_range(buddy, order, migratetype);
}
+ page_zeroed = PageZeroed(page);
+ __ClearPageZeroed(page);
+ __ClearPageZeroed(buddy);
+
combined_pfn = buddy_pfn & pfn;
page = page + (combined_pfn - pfn);
pfn = combined_pfn;
order++;
+
+ if (page_zeroed && buddy_zeroed)
+ __SetPageZeroed(page);
}
done_merging:
--
MST
^ permalink raw reply related
* [PATCH v8 24/37] mm: page_reporting: add per-page zeroed bitmap for host feedback
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
The host may skip zeroing some reported pages (e.g., due to alignment
constraints or bounce buffer fallback in QEMU). Currently, when
host_zeroes_pages is set, all reported pages are unconditionally
marked PG_zeroed - even ones the host did not actually zero.
Add a zeroed_bitmap to page_reporting_dev_info that the report()
callback can use to indicate which pages were actually zeroed.
The driver's report() callback is responsible for managing the
bitmap: zeroing it before sending pages to the host, then setting
bits for pages the host actually zeroed.
page_reporting_drain() checks the bitmap per-page in addition to the
global host_zeroes_pages flag.
No driver sets host_zeroes_pages yet, so the static key is
off and the bitmap is never read. Behavior is unchanged.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
include/linux/page_reporting.h | 7 +++++++
mm/page_reporting.c | 8 ++++++--
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/linux/page_reporting.h b/include/linux/page_reporting.h
index c331c6b36687..e2e6a487ddab 100644
--- a/include/linux/page_reporting.h
+++ b/include/linux/page_reporting.h
@@ -17,6 +17,13 @@ struct page_reporting_dev_info {
/* If true, host zeros reported pages on reclaim */
bool host_zeroes_pages;
+ /*
+ * Per-page zeroed status, indexed by scatterlist position.
+ * The driver's report() callback must clear the bitmap,
+ * then set bits for pages that were actually zeroed.
+ */
+ DECLARE_BITMAP(zeroed_bitmap, PAGE_REPORTING_CAPACITY);
+
/* work struct for processing reports */
struct delayed_work work;
diff --git a/mm/page_reporting.c b/mm/page_reporting.c
index e42f857485ce..691a9e66aa5b 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -108,6 +108,7 @@ page_reporting_drain(struct page_reporting_dev_info *prdev,
struct scatterlist *sgl, unsigned int nents, bool reported)
{
struct scatterlist *sg = sgl;
+ unsigned int i = 0;
/*
* Drain the now reported pages back into their respective
@@ -122,7 +123,7 @@ page_reporting_drain(struct page_reporting_dev_info *prdev,
/* If the pages were not reported due to error skip flagging */
if (!reported)
- continue;
+ goto next;
/*
* If page was not commingled with another page we can
@@ -133,9 +134,12 @@ page_reporting_drain(struct page_reporting_dev_info *prdev,
*/
if (PageBuddy(page) && buddy_order(page) == order) {
__SetPageReported(page);
- if (page_reporting_host_zeroes_pages())
+ if (page_reporting_host_zeroes_pages() &&
+ test_bit(i, prdev->zeroed_bitmap))
__SetPageZeroed(page);
}
+next:
+ i++;
} while ((sg = sg_next(sg)));
/* reinitialize scatterlist now that it is empty */
--
MST
^ permalink raw reply related
* [PATCH v8 23/37] mm: page_alloc: use aliasing checks instead of user_alloc_needs_zeroing
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Replace user_alloc_needs_zeroing() with the direct aliasing checks
(cpu_dcache_is_aliasing() || cpu_icache_is_aliasing()) in the
post_alloc_hook aliasing guard.
user_alloc_needs_zeroing() includes a !init_on_alloc term that
means "allocator didn't zero this page." But in this guard's
context (!zeroed && !init && __GFP_ZERO), we already know the page
is zero; init incorporates init_on_alloc via want_init_on_alloc().
The only question left is whether the cache architecture needs
the data re-zeroed through a congruent mapping, which is purely
cpu_dcache_is_aliasing() || cpu_icache_is_aliasing().
On non-aliasing architectures with init_on_free=true and
init_on_alloc=false, this avoids a redundant re-zero of an
already-zero page.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
mm/page_alloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5158f7e23d18..4cb7e779a6c5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1883,7 +1883,7 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
*/
if (!zeroed && !init && (gfp_flags & __GFP_ZERO) &&
user_addr != USER_ADDR_NONE &&
- user_alloc_needs_zeroing())
+ (cpu_dcache_is_aliasing() || cpu_icache_is_aliasing()))
init = true;
/*
* If memory is still not initialized, initialize it now.
--
MST
^ permalink raw reply related
* [PATCH v8 22/37] mm: page_reporting: skip redundant zeroing of host-zeroed reported pages
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
When a guest reports free pages to the hypervisor via the page reporting
framework (used by virtio-balloon and hv_balloon), the host typically
zeros those pages when reclaiming their backing memory. However, when
those pages are later allocated in the guest, post_alloc_hook()
unconditionally zeros them again if __GFP_ZERO is set. This
double-zeroing is wasteful, especially for large pages.
Avoid redundant zeroing:
- Add a host_zeroes_pages flag to page_reporting_dev_info, allowing
drivers to declare that their host zeros reported pages on reclaim.
A static key (page_reporting_host_zeroes) gates the fast path.
- Add PG_zeroed page flag (sharing PG_private bit) to mark pages
that have been zeroed by the host. Set it in
page_reporting_drain() after the host reports them.
- Thread the zeroed bool through rmqueue -> prep_new_page ->
post_alloc_hook, where it skips redundant zeroing for __GFP_ZERO
allocations.
No driver sets host_zeroes_pages yet; a follow-up patch to
virtio_balloon is needed to opt in.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
include/linux/page-flags.h | 9 +++++
include/linux/page_reporting.h | 3 ++
mm/compaction.c | 6 ++-
mm/internal.h | 2 +-
mm/page_alloc.c | 68 +++++++++++++++++++++++-----------
mm/page_reporting.c | 14 ++++++-
mm/page_reporting.h | 12 ++++++
7 files changed, 88 insertions(+), 26 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 0e03d816e8b9..4ee64134acc3 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -135,6 +135,8 @@ enum pageflags {
PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */
/* Some filesystems */
PG_checked = PG_owner_priv_1,
+ /* Page contents are known to be zero */
+ PG_zeroed = PG_private,
/*
* Depending on the way an anonymous folio can be mapped into a page
@@ -673,6 +675,13 @@ FOLIO_TEST_CLEAR_FLAG_FALSE(young)
FOLIO_FLAG_FALSE(idle)
#endif
+/*
+ * PageZeroed() tracks pages known to be zero. The allocator
+ * uses this to skip redundant zeroing in post_alloc_hook().
+ */
+__PAGEFLAG(Zeroed, zeroed, PF_NO_COMPOUND)
+#define __PG_ZEROED (1UL << PG_zeroed)
+
/*
* PageReported() is used to track reported free pages within the Buddy
* allocator. We can use the non-atomic version of the test and set
diff --git a/include/linux/page_reporting.h b/include/linux/page_reporting.h
index 5ab5be02fa15..c331c6b36687 100644
--- a/include/linux/page_reporting.h
+++ b/include/linux/page_reporting.h
@@ -14,6 +14,9 @@ struct page_reporting_dev_info {
int (*report)(struct page_reporting_dev_info *prdev,
struct scatterlist *sg, unsigned int nents);
+ /* If true, host zeros reported pages on reclaim */
+ bool host_zeroes_pages;
+
/* work struct for processing reports */
struct delayed_work work;
diff --git a/mm/compaction.c b/mm/compaction.c
index 4336e433c99b..8000fc5e0a2e 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -82,7 +82,8 @@ static inline bool is_via_compact_memory(int order) { return false; }
static struct page *mark_allocated_noprof(struct page *page, unsigned int order, gfp_t gfp_flags)
{
- post_alloc_hook(page, order, __GFP_MOVABLE, USER_ADDR_NONE);
+ __ClearPageZeroed(page);
+ post_alloc_hook(page, order, __GFP_MOVABLE, false, USER_ADDR_NONE);
set_page_refcounted(page);
return page;
}
@@ -1849,9 +1850,10 @@ static struct folio *compaction_alloc_noprof(struct folio *src, unsigned long da
set_page_private(&freepage[size], start_order);
}
dst = (struct folio *)freepage;
+ __ClearPageZeroed(&dst->page);
if (order)
prep_compound_page(&dst->page, order);
- post_alloc_hook(&dst->page, order, __GFP_MOVABLE, USER_ADDR_NONE);
+ post_alloc_hook(&dst->page, order, __GFP_MOVABLE, false, USER_ADDR_NONE);
set_page_refcounted(&dst->page);
cc->nr_freepages -= 1 << order;
cc->nr_migratepages -= 1 << order;
diff --git a/mm/internal.h b/mm/internal.h
index 389098200aa6..fd910743ddc3 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -928,7 +928,7 @@ static inline void init_compound_tail(struct page *tail,
}
void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags,
- unsigned long user_addr);
+ bool zeroed, unsigned long user_addr);
extern bool free_pages_prepare(struct page *page, unsigned int order);
extern int user_min_free_kbytes;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ad0655387e9d..5158f7e23d18 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1746,6 +1746,7 @@ static __always_inline void page_del_and_expand(struct zone *zone,
bool was_reported = page_reported(page);
__del_page_from_free_list(page, zone, high, migratetype);
+
nr_pages -= expand(zone, page, low, high, migratetype, was_reported);
account_freepages(zone, -nr_pages, migratetype);
}
@@ -1818,8 +1819,10 @@ static inline bool should_skip_init(gfp_t flags)
return (flags & __GFP_SKIP_ZERO);
}
+
inline void post_alloc_hook(struct page *page, unsigned int order,
- gfp_t gfp_flags, unsigned long user_addr)
+ gfp_t gfp_flags, bool zeroed,
+ unsigned long user_addr)
{
bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags) &&
!should_skip_init(gfp_flags);
@@ -1828,6 +1831,14 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
set_page_private(page, 0);
+ /*
+ * If the page is zeroed, skip memory initialization.
+ * We still need to handle tag zeroing separately since the host
+ * does not know about memory tags.
+ */
+ if (zeroed && init && !zero_tags)
+ init = false;
+
arch_alloc_page(page, order);
debug_pagealloc_map_pages(page, 1 << order);
@@ -1870,7 +1881,7 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
* through a user-congruent mapping. Host-zeroed pages
* (zeroed flag) don't need this: physical RAM is clean.
*/
- if (!init && (gfp_flags & __GFP_ZERO) &&
+ if (!zeroed && !init && (gfp_flags & __GFP_ZERO) &&
user_addr != USER_ADDR_NONE &&
user_alloc_needs_zeroing())
init = true;
@@ -1903,13 +1914,13 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
}
static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
- unsigned int alloc_flags,
- unsigned long user_addr)
+ unsigned int alloc_flags, bool zeroed,
+ unsigned long user_addr)
{
if (order && (gfp_flags & __GFP_COMP))
prep_compound_page(page, order);
- post_alloc_hook(page, order, gfp_flags, user_addr);
+ post_alloc_hook(page, order, gfp_flags, zeroed, user_addr);
/*
* page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
@@ -3175,6 +3186,7 @@ int __isolate_free_page(struct page *page, unsigned int order)
}
del_page_from_free_list(page, zone, order, mt);
+ __ClearPageZeroed(page);
/*
* Set the pageblock if the isolated page is at least half of a
@@ -3247,7 +3259,7 @@ static inline void zone_statistics(struct zone *preferred_zone, struct zone *z,
static __always_inline
struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone,
unsigned int order, unsigned int alloc_flags,
- int migratetype)
+ int migratetype, bool *zeroed)
{
struct page *page;
unsigned long flags;
@@ -3282,6 +3294,8 @@ struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone,
}
}
spin_unlock_irqrestore(&zone->lock, flags);
+ *zeroed = PageZeroed(page);
+ __ClearPageZeroed(page);
} while (check_new_pages(page, order));
/*
@@ -3350,10 +3364,9 @@ static int nr_pcp_alloc(struct per_cpu_pages *pcp, struct zone *zone, int order)
/* Remove page from the per-cpu list, caller must protect the list */
static inline
struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order,
- int migratetype,
- unsigned int alloc_flags,
+ int migratetype, unsigned int alloc_flags,
struct per_cpu_pages *pcp,
- struct list_head *list)
+ struct list_head *list, bool *zeroed)
{
struct page *page;
@@ -3388,6 +3401,8 @@ struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order,
page = list_first_entry(list, struct page, pcp_list);
list_del(&page->pcp_list);
pcp->count -= 1 << order;
+ *zeroed = PageZeroed(page);
+ __ClearPageZeroed(page);
} while (check_new_pages(page, order));
return page;
@@ -3396,7 +3411,8 @@ struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order,
/* Lock and remove page from the per-cpu list */
static struct page *rmqueue_pcplist(struct zone *preferred_zone,
struct zone *zone, unsigned int order,
- int migratetype, unsigned int alloc_flags)
+ int migratetype, unsigned int alloc_flags,
+ bool *zeroed)
{
struct per_cpu_pages *pcp;
struct list_head *list;
@@ -3414,7 +3430,8 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone,
*/
pcp->free_count >>= 1;
list = &pcp->lists[order_to_pindex(migratetype, order)];
- page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags, pcp, list);
+ page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags,
+ pcp, list, zeroed);
pcp_spin_unlock(pcp);
if (page) {
__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
@@ -3439,19 +3456,19 @@ static inline
struct page *rmqueue(struct zone *preferred_zone,
struct zone *zone, unsigned int order,
gfp_t gfp_flags, unsigned int alloc_flags,
- int migratetype)
+ int migratetype, bool *zeroed)
{
struct page *page;
if (likely(pcp_allowed_order(order))) {
page = rmqueue_pcplist(preferred_zone, zone, order,
- migratetype, alloc_flags);
+ migratetype, alloc_flags, zeroed);
if (likely(page))
goto out;
}
page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags,
- migratetype);
+ migratetype, zeroed);
out:
/* Separate test+clear to avoid unnecessary atomics */
@@ -3842,6 +3859,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
struct pglist_data *last_pgdat = NULL;
bool last_pgdat_dirty_ok = false;
bool no_fallback;
+ bool zeroed;
bool skip_kswapd_nodes = nr_online_nodes > 1;
bool skipped_kswapd_nodes = false;
@@ -3986,10 +4004,11 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
try_this_zone:
page = rmqueue(zonelist_zone(ac->preferred_zoneref), zone, order,
- gfp_mask, alloc_flags, ac->migratetype);
+ gfp_mask, alloc_flags, ac->migratetype,
+ &zeroed);
if (page) {
prep_new_page(page, order, gfp_mask, alloc_flags,
- ac->user_addr);
+ zeroed, ac->user_addr);
return page;
} else {
@@ -4216,9 +4235,11 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
count_vm_event(COMPACTSTALL);
/* Prep a captured page if available */
- if (page)
- prep_new_page(page, order, gfp_mask, alloc_flags,
+ if (page) {
+ __ClearPageZeroed(page);
+ prep_new_page(page, order, gfp_mask, alloc_flags, false,
ac->user_addr);
+ }
/* Try get a page from the freelist if available */
if (!page)
@@ -5191,6 +5212,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
/* Attempt the batch allocation */
pcp_list = &pcp->lists[order_to_pindex(ac.migratetype, 0)];
while (nr_populated < nr_pages) {
+ bool zeroed = false;
/* Skip existing pages */
if (page_array[nr_populated]) {
@@ -5199,7 +5221,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
}
page = __rmqueue_pcplist(zone, 0, ac.migratetype, alloc_flags,
- pcp, pcp_list);
+ pcp, pcp_list, &zeroed);
if (unlikely(!page)) {
/* Try and allocate at least one page */
if (!nr_account) {
@@ -5210,7 +5232,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
}
nr_account++;
- prep_new_page(page, 0, gfp, 0, USER_ADDR_NONE);
+ prep_new_page(page, 0, gfp, 0, zeroed, USER_ADDR_NONE);
set_page_refcounted(page);
page_array[nr_populated++] = page;
}
@@ -6950,7 +6972,8 @@ static void split_free_frozen_pages(struct list_head *list, gfp_t gfp_mask)
list_for_each_entry_safe(page, next, &list[order], lru) {
int i;
- post_alloc_hook(page, order, gfp_mask, USER_ADDR_NONE);
+ __ClearPageZeroed(page);
+ post_alloc_hook(page, order, gfp_mask, false, USER_ADDR_NONE);
if (!order)
continue;
@@ -7156,8 +7179,9 @@ static int __alloc_contig_frozen_range(unsigned long start, unsigned long end,
} else if (start == outer_start && end == outer_end && is_power_of_2(end - start)) {
struct page *head = pfn_to_page(start);
+ __ClearPageZeroed(head);
check_new_pages(head, order);
- prep_new_page(head, order, gfp_mask, 0, user_addr);
+ prep_new_page(head, order, gfp_mask, 0, false, user_addr);
} else {
ret = -EINVAL;
WARN(true, "PFN range: requested [%lu, %lu), allocated [%lu, %lu)\n",
diff --git a/mm/page_reporting.c b/mm/page_reporting.c
index ae8d55f89f25..e42f857485ce 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -50,6 +50,8 @@ EXPORT_SYMBOL_GPL(page_reporting_order);
#define PAGE_REPORTING_DELAY (2 * HZ)
static struct page_reporting_dev_info __rcu *pr_dev_info __read_mostly;
+DEFINE_STATIC_KEY_FALSE(page_reporting_host_zeroes);
+
enum {
PAGE_REPORTING_IDLE = 0,
PAGE_REPORTING_REQUESTED,
@@ -129,8 +131,11 @@ page_reporting_drain(struct page_reporting_dev_info *prdev,
* report on the new larger page when we make our way
* up to that higher order.
*/
- if (PageBuddy(page) && buddy_order(page) == order)
+ if (PageBuddy(page) && buddy_order(page) == order) {
__SetPageReported(page);
+ if (page_reporting_host_zeroes_pages())
+ __SetPageZeroed(page);
+ }
} while ((sg = sg_next(sg)));
/* reinitialize scatterlist now that it is empty */
@@ -393,6 +398,10 @@ int page_reporting_register(struct page_reporting_dev_info *prdev)
/* Assign device to allow notifications */
rcu_assign_pointer(pr_dev_info, prdev);
+ /* enable zeroed page optimization if host zeroes reported pages */
+ if (prdev->host_zeroes_pages)
+ static_branch_enable(&page_reporting_host_zeroes);
+
/* enable page reporting notification */
if (!static_key_enabled(&page_reporting_enabled)) {
static_branch_enable(&page_reporting_enabled);
@@ -417,6 +426,9 @@ void page_reporting_unregister(struct page_reporting_dev_info *prdev)
/* Flush any existing work, and lock it out */
cancel_delayed_work_sync(&prdev->work);
+
+ if (prdev->host_zeroes_pages)
+ static_branch_disable(&page_reporting_host_zeroes);
}
mutex_unlock(&page_reporting_mutex);
diff --git a/mm/page_reporting.h b/mm/page_reporting.h
index c51dbc228b94..736ea7b37e9e 100644
--- a/mm/page_reporting.h
+++ b/mm/page_reporting.h
@@ -15,6 +15,13 @@ DECLARE_STATIC_KEY_FALSE(page_reporting_enabled);
extern unsigned int page_reporting_order;
void __page_reporting_notify(void);
+DECLARE_STATIC_KEY_FALSE(page_reporting_host_zeroes);
+
+static inline bool page_reporting_host_zeroes_pages(void)
+{
+ return static_branch_unlikely(&page_reporting_host_zeroes);
+}
+
static inline bool page_reported(struct page *page)
{
return static_branch_unlikely(&page_reporting_enabled) &&
@@ -46,6 +53,11 @@ static inline void page_reporting_notify_free(unsigned int order)
#else /* CONFIG_PAGE_REPORTING */
#define page_reported(_page) false
+static inline bool page_reporting_host_zeroes_pages(void)
+{
+ return false;
+}
+
static inline void page_reporting_notify_free(unsigned int order)
{
}
--
MST
^ permalink raw reply related
* [PATCH v8 21/37] mm: memfd: skip zeroing for zeroed hugetlb pool pages
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Add bool *zeroed output to alloc_hugetlb_folio_reserve() so
callers can check whether the pool page is known-zero. memfd's
memfd_alloc_folio() uses this to skip the explicit folio_zero_user()
when the page is already zero.
This avoids redundant zeroing for memfd hugetlb pages that were
pre-allocated into the pool and never mapped to userspace.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
include/linux/cma.h | 3 ++-
include/linux/hugetlb.h | 6 ++++--
mm/cma.c | 6 ++++--
mm/hugetlb.c | 11 +++++++++--
mm/hugetlb_cma.c | 4 ++--
mm/memfd.c | 14 ++++++++------
6 files changed, 29 insertions(+), 15 deletions(-)
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 8555d38a97b1..dee88909cf5d 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -53,7 +53,8 @@ extern bool cma_release(struct cma *cma, const struct page *pages, unsigned long
struct page *cma_alloc_frozen(struct cma *cma, unsigned long count,
unsigned int align, bool no_warn);
-struct page *cma_alloc_frozen_compound(struct cma *cma, unsigned int order);
+struct page *cma_alloc_frozen_compound(struct cma *cma, unsigned int order,
+ gfp_t caller_gfp);
bool cma_release_frozen(struct cma *cma, const struct page *pages,
unsigned long count);
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 49e5557d6cc0..3d23267014e6 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -714,7 +714,8 @@ struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid,
nodemask_t *nmask, gfp_t gfp_mask,
bool allow_alloc_fallback);
struct folio *alloc_hugetlb_folio_reserve(struct hstate *h, int preferred_nid,
- nodemask_t *nmask, gfp_t gfp_mask);
+ nodemask_t *nmask, gfp_t gfp_mask,
+ bool *zeroed);
int hugetlb_add_to_page_cache(struct folio *folio, struct address_space *mapping,
pgoff_t idx);
@@ -1134,7 +1135,8 @@ static inline void wait_for_freed_hugetlb_folios(void)
static inline struct folio *
alloc_hugetlb_folio_reserve(struct hstate *h, int preferred_nid,
- nodemask_t *nmask, gfp_t gfp_mask)
+ nodemask_t *nmask, gfp_t gfp_mask,
+ bool *zeroed)
{
return NULL;
}
diff --git a/mm/cma.c b/mm/cma.c
index c7ca567f4c5c..27971f6264ab 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -924,9 +924,11 @@ struct page *cma_alloc_frozen(struct cma *cma, unsigned long count,
return __cma_alloc_frozen(cma, count, align, gfp);
}
-struct page *cma_alloc_frozen_compound(struct cma *cma, unsigned int order)
+struct page *cma_alloc_frozen_compound(struct cma *cma, unsigned int order,
+ gfp_t caller_gfp)
{
- gfp_t gfp = GFP_KERNEL | __GFP_COMP | __GFP_NOWARN;
+ gfp_t gfp = GFP_KERNEL | __GFP_COMP | __GFP_NOWARN |
+ (caller_gfp & __GFP_ZERO);
return __cma_alloc_frozen(cma, 1 << order, order, gfp);
}
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4ccf4eb91d92..649972101ace 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2208,7 +2208,7 @@ struct folio *alloc_buddy_hugetlb_folio_with_mpol(struct hstate *h,
}
struct folio *alloc_hugetlb_folio_reserve(struct hstate *h, int preferred_nid,
- nodemask_t *nmask, gfp_t gfp_mask)
+ nodemask_t *nmask, gfp_t gfp_mask, bool *zeroed)
{
struct folio *folio;
@@ -2224,6 +2224,12 @@ struct folio *alloc_hugetlb_folio_reserve(struct hstate *h, int preferred_nid,
h->resv_huge_pages--;
spin_unlock_irq(&hugetlb_lock);
+
+ if (zeroed && folio) {
+ *zeroed = folio_test_hugetlb_zeroed(folio);
+ folio_clear_hugetlb_zeroed(folio);
+ }
+
return folio;
}
@@ -2308,7 +2314,8 @@ static int gather_surplus_pages(struct hstate *h, long delta)
* It is okay to use NUMA_NO_NODE because we use numa_mem_id()
* down the road to pick the current node if that is the case.
*/
- folio = alloc_surplus_hugetlb_folio(h, htlb_alloc_mask(h),
+ folio = alloc_surplus_hugetlb_folio(h,
+ htlb_alloc_mask(h),
NUMA_NO_NODE, &alloc_nodemask,
USER_ADDR_NONE);
if (!folio) {
diff --git a/mm/hugetlb_cma.c b/mm/hugetlb_cma.c
index 7693ccefd0c6..c9266b25be3d 100644
--- a/mm/hugetlb_cma.c
+++ b/mm/hugetlb_cma.c
@@ -35,14 +35,14 @@ struct folio *hugetlb_cma_alloc_frozen_folio(int order, gfp_t gfp_mask,
return NULL;
if (hugetlb_cma[nid])
- page = cma_alloc_frozen_compound(hugetlb_cma[nid], order);
+ page = cma_alloc_frozen_compound(hugetlb_cma[nid], order, gfp_mask);
if (!page && !(gfp_mask & __GFP_THISNODE)) {
for_each_node_mask(node, *nodemask) {
if (node == nid || !hugetlb_cma[node])
continue;
- page = cma_alloc_frozen_compound(hugetlb_cma[node], order);
+ page = cma_alloc_frozen_compound(hugetlb_cma[node], order, gfp_mask);
if (page)
break;
}
diff --git a/mm/memfd.c b/mm/memfd.c
index fb425f4e315f..5518f7d2d91f 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -69,6 +69,7 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx)
#ifdef CONFIG_HUGETLB_PAGE
struct folio *folio;
gfp_t gfp_mask;
+ bool zeroed;
if (is_file_hugepages(memfd)) {
/*
@@ -93,17 +94,18 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx)
folio = alloc_hugetlb_folio_reserve(h,
numa_node_id(),
NULL,
- gfp_mask);
+ gfp_mask,
+ &zeroed);
if (folio) {
u32 hash;
/*
- * Zero the folio to prevent information leaks to userspace.
- * Use folio_zero_user() which is optimized for huge/gigantic
- * pages. Pass 0 as addr_hint since this is not a faulting path
- * and we don't have a user virtual address yet.
+ * Zero the folio to prevent information leaks to
+ * userspace. Skip if the pool page is known-zero
+ * (HPG_zeroed set during pool pre-allocation).
*/
- folio_zero_user(folio, 0);
+ if (!zeroed)
+ folio_zero_user(folio, 0);
/*
* Mark the folio uptodate before adding to page cache,
--
MST
^ permalink raw reply related
* [PATCH v8 20/37] mm: hugetlb: add gfp parameter and skip zeroing for zeroed pages
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Add a gfp_t parameter to alloc_hugetlb_folio(). When __GFP_ZERO
is set, the function guarantees the returned folio is zeroed:
- Fresh allocations (buddy or gigantic): zeroed by
post_alloc_hook via __GFP_ZERO, HPG_zeroed set by
alloc_surplus_hugetlb_folio.
- Pool pages with HPG_zeroed set: already zeroed, skip.
- Pool pages without HPG_zeroed: zeroed via folio_zero_user().
The address parameter is renamed to user_addr; the function
aligns it internally for reservation and NUMA policy lookups.
For pages that need zeroing, user_addr is passed to
folio_zero_user() for cache-friendly zeroing near the faulting
subpage. All callers pass a page-aligned address; the
hugetlb_no_page caller passes vmf->real_address & PAGE_MASK
for consistency.
HPG_zeroed (stored in hugetlb folio->private bits) tracks
known-zero pool pages. It is set when alloc_surplus_hugetlb_folio
allocates with __GFP_ZERO, and cleared in free_huge_folio when
the page returns to the pool after userspace use.
Suggested-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Gregory Price <gourry@gourry.net>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
fs/hugetlbfs/inode.c | 3 +--
include/linux/hugetlb.h | 5 ++++-
mm/hugetlb.c | 42 +++++++++++++++++++++++++++++------------
3 files changed, 35 insertions(+), 15 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 8b05bec08e04..5856a3530c7b 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -810,13 +810,12 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
* folios in these areas, we need to consume the reserves
* to keep reservation accounting consistent.
*/
- folio = alloc_hugetlb_folio(&pseudo_vma, addr, false);
+ folio = alloc_hugetlb_folio(&pseudo_vma, addr, false, __GFP_ZERO);
if (IS_ERR(folio)) {
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
error = PTR_ERR(folio);
goto out;
}
- folio_zero_user(folio, addr);
__folio_mark_uptodate(folio);
error = hugetlb_add_to_page_cache(folio, mapping, index);
if (unlikely(error)) {
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index f016bc2e8936..49e5557d6cc0 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -599,6 +599,7 @@ enum hugetlb_page_flags {
HPG_vmemmap_optimized,
HPG_raw_hwp_unreliable,
HPG_cma,
+ HPG_zeroed,
__NR_HPAGEFLAGS,
};
@@ -659,6 +660,7 @@ HPAGEFLAG(Freed, freed)
HPAGEFLAG(VmemmapOptimized, vmemmap_optimized)
HPAGEFLAG(RawHwpUnreliable, raw_hwp_unreliable)
HPAGEFLAG(Cma, cma)
+HPAGEFLAG(Zeroed, zeroed)
#ifdef CONFIG_HUGETLB_PAGE
@@ -706,7 +708,8 @@ int isolate_or_dissolve_huge_folio(struct folio *folio, struct list_head *list);
int replace_free_hugepage_folios(unsigned long start_pfn, unsigned long end_pfn);
void wait_for_freed_hugetlb_folios(void);
struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
- unsigned long addr, bool cow_from_owner);
+ unsigned long user_addr, bool cow_from_owner,
+ gfp_t gfp);
struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid,
nodemask_t *nmask, gfp_t gfp_mask,
bool allow_alloc_fallback);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3a6afbe99116..4ccf4eb91d92 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1712,6 +1712,9 @@ void free_huge_folio(struct folio *folio)
bool restore_reserve;
unsigned long flags;
+ /* Page was mapped to userspace; no longer known-zero */
+ folio_clear_hugetlb_zeroed(folio);
+
VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
VM_BUG_ON_FOLIO(folio_mapcount(folio), folio);
@@ -2113,6 +2116,10 @@ static struct folio *alloc_surplus_hugetlb_folio(struct hstate *h,
if (!folio)
return NULL;
+ /* Mark as known-zero only if __GFP_ZERO was requested */
+ if (gfp_mask & __GFP_ZERO)
+ folio_set_hugetlb_zeroed(folio);
+
spin_lock_irq(&hugetlb_lock);
/*
* nr_huge_pages needs to be adjusted within the same lock cycle
@@ -2176,11 +2183,11 @@ static struct folio *alloc_migrate_hugetlb_folio(struct hstate *h, gfp_t gfp_mas
*/
static
struct folio *alloc_buddy_hugetlb_folio_with_mpol(struct hstate *h,
- struct vm_area_struct *vma, unsigned long addr)
+ struct vm_area_struct *vma, unsigned long addr, gfp_t gfp)
{
struct folio *folio = NULL;
struct mempolicy *mpol;
- gfp_t gfp_mask = htlb_alloc_mask(h);
+ gfp_t gfp_mask = htlb_alloc_mask(h) | gfp;
int nid;
nodemask_t *nodemask;
@@ -2877,16 +2884,19 @@ typedef enum {
* When it's set, the allocation will bypass all vma level reservations.
*/
struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
- unsigned long addr, bool cow_from_owner)
+ unsigned long user_addr, bool cow_from_owner,
+ gfp_t gfp)
{
struct hugepage_subpool *spool = subpool_vma(vma);
struct hstate *h = hstate_vma(vma);
+ unsigned long addr = user_addr & huge_page_mask(h);
struct folio *folio;
long retval, gbl_chg, gbl_reserve;
map_chg_state map_chg;
int ret, idx;
struct hugetlb_cgroup *h_cg = NULL;
- gfp_t gfp = htlb_alloc_mask(h) | __GFP_RETRY_MAYFAIL;
+
+ gfp |= htlb_alloc_mask(h) | __GFP_RETRY_MAYFAIL;
idx = hstate_index(h);
@@ -2954,13 +2964,12 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
folio = dequeue_hugetlb_folio_vma(h, vma, addr, gbl_chg);
if (!folio) {
spin_unlock_irq(&hugetlb_lock);
- folio = alloc_buddy_hugetlb_folio_with_mpol(h, vma, addr);
+ folio = alloc_buddy_hugetlb_folio_with_mpol(h, vma, user_addr, gfp);
if (!folio)
goto out_uncharge_cgroup;
spin_lock_irq(&hugetlb_lock);
list_add(&folio->lru, &h->hugepage_activelist);
folio_ref_unfreeze(folio, 1);
- /* Fall through */
}
/*
@@ -2983,6 +2992,10 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
spin_unlock_irq(&hugetlb_lock);
+ if ((gfp & __GFP_ZERO) && !folio_test_hugetlb_zeroed(folio))
+ folio_zero_user(folio, user_addr);
+ folio_clear_hugetlb_zeroed(folio);
+
hugetlb_set_folio_subpool(folio, spool);
if (map_chg != MAP_CHG_ENFORCED) {
@@ -4991,7 +5004,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
spin_unlock(src_ptl);
spin_unlock(dst_ptl);
/* Do not use reserve as it's private owned */
- new_folio = alloc_hugetlb_folio(dst_vma, addr, false);
+ new_folio = alloc_hugetlb_folio(dst_vma, addr, false, 0);
if (IS_ERR(new_folio)) {
folio_put(pte_folio);
ret = PTR_ERR(new_folio);
@@ -5520,7 +5533,7 @@ static vm_fault_t hugetlb_wp(struct vm_fault *vmf)
* be acquired again before returning to the caller, as expected.
*/
spin_unlock(vmf->ptl);
- new_folio = alloc_hugetlb_folio(vma, vmf->address, cow_from_owner);
+ new_folio = alloc_hugetlb_folio(vma, vmf->address, cow_from_owner, 0);
if (IS_ERR(new_folio)) {
/*
@@ -5780,7 +5793,13 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
goto out;
}
- folio = alloc_hugetlb_folio(vma, vmf->address, false);
+ /*
+ * Passing vmf->real_address would work just as well,
+ * but PAGE_MASK helps make sure we never pass
+ * USER_ADDR_NONE by mistake.
+ */
+ folio = alloc_hugetlb_folio(vma, vmf->real_address & PAGE_MASK,
+ false, __GFP_ZERO);
if (IS_ERR(folio)) {
/*
* Returning error will result in faulting task being
@@ -5800,7 +5819,6 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
ret = 0;
goto out;
}
- folio_zero_user(folio, vmf->real_address);
__folio_mark_uptodate(folio);
new_folio = true;
@@ -6239,7 +6257,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
goto out;
}
- folio = alloc_hugetlb_folio(dst_vma, dst_addr, false);
+ folio = alloc_hugetlb_folio(dst_vma, dst_addr, false, 0);
if (IS_ERR(folio)) {
pte_t *actual_pte = hugetlb_walk(dst_vma, dst_addr, PMD_SIZE);
if (actual_pte) {
@@ -6286,7 +6304,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
goto out;
}
- folio = alloc_hugetlb_folio(dst_vma, dst_addr, false);
+ folio = alloc_hugetlb_folio(dst_vma, dst_addr, false, 0);
if (IS_ERR(folio)) {
folio_put(*foliop);
ret = -ENOMEM;
--
MST
^ permalink raw reply related
* [PATCH v8 19/37] mm: use __GFP_ZERO in vma_alloc_anon_folio_pmd
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Convert vma_alloc_anon_folio_pmd() to pass __GFP_ZERO instead of
zeroing at the callsite. post_alloc_hook uses the fault address
passed through vma_alloc_folio for cache-friendly zeroing.
Note: with __GFP_ZERO, the folio is zeroed before
mem_cgroup_charge(). If the charge fails, the zeroing work is
wasted. Previously zeroing was done after a successful charge.
This is inherent to moving zeroing into the allocator.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Assisted-by: Claude:claude-opus-4-6
---
mm/huge_memory.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index d689e6491ddb..9845c920c29c 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1333,7 +1333,7 @@ EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
static struct folio *vma_alloc_anon_folio_pmd(struct vm_area_struct *vma,
unsigned long addr)
{
- gfp_t gfp = vma_thp_gfp_mask(vma);
+ gfp_t gfp = vma_thp_gfp_mask(vma) | __GFP_ZERO;
const int order = HPAGE_PMD_ORDER;
struct folio *folio;
@@ -1356,14 +1356,6 @@ static struct folio *vma_alloc_anon_folio_pmd(struct vm_area_struct *vma,
}
folio_throttle_swaprate(folio, gfp);
- /*
- * When a folio is not zeroed during allocation (__GFP_ZERO not used)
- * or user folios require special handling, folio_zero_user() is used to
- * make sure that the page corresponding to the faulting address will be
- * hot in the cache after zeroing.
- */
- if (user_alloc_needs_zeroing())
- folio_zero_user(folio, addr);
/*
* The memory barrier inside __folio_mark_uptodate makes sure that
* folio_zero_user writes become visible before the set_pmd_at()
--
MST
^ permalink raw reply related
* [PATCH v8 18/37] mm: vma_alloc_anon_folio_pmd: pass raw fault address to vma_alloc_folio
From: Michael S. Tsirkin @ 2026-05-20 22:22 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Now that vma_alloc_folio aligns the address internally, drop the
redundant HPAGE_PMD_MASK alignment at the callsite.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Reviewed-by: Gregory Price <gourry@gourry.net>
---
mm/huge_memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 970e077019b7..d689e6491ddb 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1337,7 +1337,7 @@ static struct folio *vma_alloc_anon_folio_pmd(struct vm_area_struct *vma,
const int order = HPAGE_PMD_ORDER;
struct folio *folio;
- folio = vma_alloc_folio(gfp, order, vma, addr & HPAGE_PMD_MASK);
+ folio = vma_alloc_folio(gfp, order, vma, addr);
if (unlikely(!folio)) {
count_vm_event(THP_FAULT_FALLBACK);
--
MST
^ permalink raw reply related
* [PATCH v8 17/37] mm: use __GFP_ZERO in alloc_anon_folio
From: Michael S. Tsirkin @ 2026-05-20 22:21 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Convert alloc_anon_folio() to pass __GFP_ZERO instead of zeroing
at the callsite. post_alloc_hook uses the fault address passed
through vma_alloc_folio for cache-friendly zeroing.
Note: with __GFP_ZERO, the folio is zeroed before
mem_cgroup_charge(). If the charge fails, the zeroing work is
wasted. Previously zeroing was done after a successful charge.
This is inherent to moving zeroing into the allocator.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Assisted-by: Claude:claude-opus-4-6
---
mm/memory.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index adc228fe3578..895ac72121fe 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5249,7 +5249,7 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
goto fallback;
/* Try allocating the highest of the remaining orders. */
- gfp = vma_thp_gfp_mask(vma);
+ gfp = vma_thp_gfp_mask(vma) | __GFP_ZERO;
while (orders) {
folio = vma_alloc_folio(gfp, order, vma, vmf->address);
if (folio) {
@@ -5259,15 +5259,6 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
goto next;
}
folio_throttle_swaprate(folio, gfp);
- /*
- * When a folio is not zeroed during allocation
- * (__GFP_ZERO not used) or user folios require special
- * handling, folio_zero_user() is used to make sure
- * that the page corresponding to the faulting address
- * will be hot in the cache after zeroing.
- */
- if (user_alloc_needs_zeroing())
- folio_zero_user(folio, vmf->address);
return folio;
}
next:
--
MST
^ permalink raw reply related
* [PATCH v8 16/37] mm: alloc_swap_folio: pass raw fault address to vma_alloc_folio
From: Michael S. Tsirkin @ 2026-05-20 22:21 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Same change as the previous patch but for alloc_swap_folio:
pass vmf->address directly instead of ALIGN_DOWN(vmf->address, ...).
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
mm/memory.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 75bee9501666..adc228fe3578 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4734,8 +4734,7 @@ static struct folio *alloc_swap_folio(struct vm_fault *vmf)
/* Try allocating the highest of the remaining orders. */
gfp = vma_thp_gfp_mask(vma);
while (orders) {
- addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order);
- folio = vma_alloc_folio(gfp, order, vma, addr);
+ folio = vma_alloc_folio(gfp, order, vma, vmf->address);
if (folio) {
if (!mem_cgroup_swapin_charge_folio(folio, vma->vm_mm,
gfp, entry))
--
MST
^ permalink raw reply related
* [PATCH v8 15/37] mm: alloc_anon_folio: pass raw fault address to vma_alloc_folio
From: Michael S. Tsirkin @ 2026-05-20 22:21 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Pass vmf->address directly instead of ALIGN_DOWN(vmf->address, ...).
vma_alloc_folio_noprof now aligns internally for NUMA interleave,
and post_alloc_hook will use the raw address for cache-friendly
zeroing via folio_zero_user().
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
mm/memory.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 02d3e53fc91b..75bee9501666 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5252,8 +5252,7 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
/* Try allocating the highest of the remaining orders. */
gfp = vma_thp_gfp_mask(vma);
while (orders) {
- addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order);
- folio = vma_alloc_folio(gfp, order, vma, addr);
+ folio = vma_alloc_folio(gfp, order, vma, vmf->address);
if (folio) {
if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) {
count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
--
MST
^ permalink raw reply related
* [PATCH v8 14/37] mm: remove arch vma_alloc_zeroed_movable_folio overrides
From: Michael S. Tsirkin @ 2026-05-20 22:21 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli, Magnus Lindholm,
Greg Ungerer, Geert Uytterhoeven, Richard Henderson, Matt Turner,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
linux-alpha, linux-m68k, linux-s390
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Now that the generic vma_alloc_zeroed_movable_folio() uses
__GFP_ZERO, the arch-specific macros on alpha, m68k, s390, and
x86 that did the same thing are redundant. Remove them.
arm64 is not affected: it has a real function override that
handles MTE tag zeroing, not just __GFP_ZERO.
Suggested-by: David Hildenbrand <david@kernel.org>
Acked-by: Magnus Lindholm <linmag7@gmail.com>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Reviewed-by: Gregory Price <gourry@gourry.net>
---
arch/alpha/include/asm/page.h | 3 ---
arch/m68k/include/asm/page_no.h | 3 ---
arch/s390/include/asm/page.h | 3 ---
arch/x86/include/asm/page.h | 3 ---
include/linux/highmem.h | 8 +++++---
5 files changed, 5 insertions(+), 15 deletions(-)
diff --git a/arch/alpha/include/asm/page.h b/arch/alpha/include/asm/page.h
index 59d01f9b77f6..4327029cd660 100644
--- a/arch/alpha/include/asm/page.h
+++ b/arch/alpha/include/asm/page.h
@@ -12,9 +12,6 @@
extern void clear_page(void *page);
-#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
- vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr)
-
extern void copy_page(void * _to, void * _from);
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
diff --git a/arch/m68k/include/asm/page_no.h b/arch/m68k/include/asm/page_no.h
index d2532bc407ef..f511b763a235 100644
--- a/arch/m68k/include/asm/page_no.h
+++ b/arch/m68k/include/asm/page_no.h
@@ -12,9 +12,6 @@ extern unsigned long memory_end;
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
-#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
- vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr)
-
#define __pa(vaddr) ((unsigned long)(vaddr))
#define __va(paddr) ((void *)((unsigned long)(paddr)))
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 56da819a79e6..e995d2a413f9 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -67,9 +67,6 @@ static inline void copy_page(void *to, void *from)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
-#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
- vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr)
-
#ifdef CONFIG_STRICT_MM_TYPECHECKS
#define STRICT_MM_TYPECHECKS
#endif
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 416dc88e35c1..92fa975b46f3 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -28,9 +28,6 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
copy_page(to, from);
}
-#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
- vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr)
-
#ifndef __pa
#define __pa(x) __phys_addr((unsigned long)(x))
#endif
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index ffa683f64f1d..7b5955bf9336 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -303,7 +303,6 @@ static inline void clear_user_highpages(struct page *page, unsigned long vaddr,
#endif
}
-#ifndef vma_alloc_zeroed_movable_folio
/**
* vma_alloc_zeroed_movable_folio - Allocate a zeroed page for a VMA.
* @vma: The VMA the page is to be allocated for.
@@ -317,12 +316,15 @@ static inline void clear_user_highpages(struct page *page, unsigned long vaddr,
* we are out of memory.
*/
static inline
-struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
+struct folio *vma_alloc_zeroed_movable_folio_noprof(struct vm_area_struct *vma,
unsigned long vaddr)
{
- return vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO,
+ return vma_alloc_folio_noprof(GFP_HIGHUSER_MOVABLE | __GFP_ZERO,
0, vma, vaddr);
}
+#ifndef vma_alloc_zeroed_movable_folio
+#define vma_alloc_zeroed_movable_folio(...) \
+ alloc_hooks(vma_alloc_zeroed_movable_folio_noprof(__VA_ARGS__))
#endif
static inline void clear_highpage(struct page *page)
--
MST
^ permalink raw reply related
* [PATCH v8 13/37] mm: use __GFP_ZERO in vma_alloc_zeroed_movable_folio
From: Michael S. Tsirkin @ 2026-05-20 22:21 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Now that post_alloc_hook() handles cache-friendly user page
zeroing via folio_zero_user(), convert vma_alloc_zeroed_movable_folio()
to pass __GFP_ZERO instead of zeroing at the callsite.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
include/linux/highmem.h | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index af03db851a1d..ffa683f64f1d 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -320,13 +320,8 @@ static inline
struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
unsigned long vaddr)
{
- struct folio *folio;
-
- folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, vaddr);
- if (folio && user_alloc_needs_zeroing())
- clear_user_highpage(&folio->page, vaddr);
-
- return folio;
+ return vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO,
+ 0, vma, vaddr);
}
#endif
--
MST
^ permalink raw reply related
* [PATCH v8 12/37] mm: use folio_zero_user for user pages in post_alloc_hook
From: Michael S. Tsirkin @ 2026-05-20 22:21 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
When post_alloc_hook() needs to zero a page for an explicit
__GFP_ZERO allocation for a user page (user_addr is set), use folio_zero_user()
instead of kernel_init_pages(). This zeros near the faulting
address last, keeping those cachelines hot for the impending
user access.
folio_zero_user() is only used for explicit __GFP_ZERO, not for
init_on_alloc. On architectures with virtually-indexed caches
(e.g., ARM), clear_user_highpage() performs per-line cache
operations; using it for init_on_alloc would add overhead that
kernel_init_pages() avoids (the page fault path flushes the
cache at PTE installation time regardless).
No functional change yet: current callers do not pass __GFP_ZERO
for user pages (they zero at the callsite instead). Subsequent
patches will convert them.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
mm/page_alloc.c | 35 ++++++++++++++++++++++++++++++++---
1 file changed, 32 insertions(+), 3 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3108ac9061ce..ad0655387e9d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1864,9 +1864,38 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
for (i = 0; i != 1 << order; ++i)
page_kasan_tag_reset(page + i);
}
- /* If memory is still not initialized, initialize it now. */
- if (init)
- kernel_init_pages(page, 1 << order);
+ /*
+ * On architectures with cache aliasing, pages zeroed via the
+ * kernel direct map (e.g. init_on_free) must be re-zeroed
+ * through a user-congruent mapping. Host-zeroed pages
+ * (zeroed flag) don't need this: physical RAM is clean.
+ */
+ if (!init && (gfp_flags & __GFP_ZERO) &&
+ user_addr != USER_ADDR_NONE &&
+ user_alloc_needs_zeroing())
+ init = true;
+ /*
+ * If memory is still not initialized, initialize it now.
+ * When __GFP_ZERO was explicitly requested and user_addr is set,
+ * use folio_zero_user() which zeros near the faulting address
+ * last, keeping those cachelines hot. For init_on_alloc, use
+ * kernel_init_pages() to avoid unnecessary cache flush overhead
+ * on architectures with virtually-indexed caches.
+ */
+ if (init) {
+ if ((gfp_flags & __GFP_ZERO) && user_addr != USER_ADDR_NONE) {
+ /*
+ * folio_zero_user relies on folio_nr_pages which
+ * requires __GFP_COMP for order > 0. All user folio
+ * allocations set __GFP_COMP via __folio_alloc.
+ * user_addr != USER_ADDR_NONE implies sleepable
+ * context (user page fault).
+ */
+ VM_WARN_ON_ONCE(order && !(gfp_flags & __GFP_COMP));
+ folio_zero_user(page_folio(page), user_addr);
+ } else
+ kernel_init_pages(page, 1 << order);
+ }
set_page_owner(page, order, gfp_flags);
page_table_check_alloc(page, order);
--
MST
^ permalink raw reply related
* [PATCH v8 11/37] mm: page_alloc: move prep_compound_page before post_alloc_hook
From: Michael S. Tsirkin @ 2026-05-20 22:21 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Move prep_compound_page() before post_alloc_hook() in prep_new_page().
The next patch adds a folio_zero_user() call to post_alloc_hook(),
which uses folio_nr_pages() to determine how many pages to zero.
Without compound metadata set up first, folio_nr_pages() returns 1
for higher-order allocations, so only the first page would be zeroed.
All other operations in post_alloc_hook() (arch_alloc_page, KASAN,
debug, page owner, etc.) use raw page pointers with explicit order
counts and are unaffected by this reordering.
Also reorder compaction_alloc_noprof() for consistency. Compaction
currently passes USER_ADDR_NONE so folio_zero_user() is not called
there, but keeping the same ordering avoids a future tripping hazard.
Reviewed-by: Gregory Price <gourry@gourry.net>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
mm/compaction.c | 4 ++--
mm/page_alloc.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index 72684fe81e83..4336e433c99b 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1849,10 +1849,10 @@ static struct folio *compaction_alloc_noprof(struct folio *src, unsigned long da
set_page_private(&freepage[size], start_order);
}
dst = (struct folio *)freepage;
- post_alloc_hook(&dst->page, order, __GFP_MOVABLE, USER_ADDR_NONE);
- set_page_refcounted(&dst->page);
if (order)
prep_compound_page(&dst->page, order);
+ post_alloc_hook(&dst->page, order, __GFP_MOVABLE, USER_ADDR_NONE);
+ set_page_refcounted(&dst->page);
cc->nr_freepages -= 1 << order;
cc->nr_migratepages -= 1 << order;
return page_rmappable_folio(&dst->page);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b725a3b59835..3108ac9061ce 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1877,11 +1877,11 @@ static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags
unsigned int alloc_flags,
unsigned long user_addr)
{
- post_alloc_hook(page, order, gfp_flags, user_addr);
-
if (order && (gfp_flags & __GFP_COMP))
prep_compound_page(page, order);
+ post_alloc_hook(page, order, gfp_flags, user_addr);
+
/*
* page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
* allocate the page. The expectation is that the caller is taking
--
MST
^ permalink raw reply related
* [PATCH v8 10/37] mm: add folio_zero_user stub for configs without THP/HUGETLBFS
From: Michael S. Tsirkin @ 2026-05-20 22:21 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
folio_zero_user() is defined in mm/memory.c under
CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS. A subsequent patch
will call it from post_alloc_hook() for all user page zeroing, so
configs without THP or HUGETLBFS will need a stub.
Add a stub that uses clear_user_highpages() with aligned
addr_hint.
Without THP/HUGETLBFS, only order-0 user pages are allocated, so
the locality optimization in the real folio_zero_user() (zero near
the faulting address last) is not needed.
This also matches what vma_alloc_zeroed_movable_folio currently does.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
include/linux/mm.h | 2 ++
mm/memory.c | 9 +++++++++
2 files changed, 11 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index af23453e9dbd..d1e768dcda13 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -5070,6 +5070,8 @@ long copy_folio_from_user(struct folio *dst_folio,
const void __user *usr_src,
bool allow_pagefault);
+#else /* !CONFIG_TRANSPARENT_HUGEPAGE && !CONFIG_HUGETLBFS */
+void folio_zero_user(struct folio *folio, unsigned long addr_hint);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
#if MAX_NUMNODES > 1
diff --git a/mm/memory.c b/mm/memory.c
index ea6568571131..02d3e53fc91b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -7546,6 +7546,15 @@ long copy_folio_from_user(struct folio *dst_folio,
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
+#if !defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_HUGETLBFS)
+void folio_zero_user(struct folio *folio, unsigned long addr_hint)
+{
+ unsigned long base = ALIGN_DOWN(addr_hint, folio_size(folio));
+
+ clear_user_highpages(&folio->page, base, folio_nr_pages(folio));
+}
+#endif
+
#if defined(CONFIG_SPLIT_PTE_PTLOCKS) && ALLOC_SPLIT_PTLOCKS
static struct kmem_cache *page_ptl_cachep;
--
MST
^ permalink raw reply related
* [PATCH v8 09/37] mm: hugetlb: thread user_addr through gigantic page allocation
From: Michael S. Tsirkin @ 2026-05-20 22:21 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Thread the user_addr parameter through alloc_gigantic_frozen_folio so that
gigantic page allocations can benefit from cache-friendly zeroing.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
mm/hugetlb.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a999f3ead852..3a6afbe99116 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1375,7 +1375,7 @@ static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h,
#if defined(CONFIG_ARCH_HAS_GIGANTIC_PAGE) && defined(CONFIG_CONTIG_ALLOC)
static struct folio *alloc_gigantic_frozen_folio(int order, gfp_t gfp_mask,
- int nid, nodemask_t *nodemask)
+ int nid, nodemask_t *nodemask, unsigned long addr)
{
struct folio *folio;
@@ -1386,13 +1386,15 @@ static struct folio *alloc_gigantic_frozen_folio(int order, gfp_t gfp_mask,
if (hugetlb_cma_exclusive_alloc())
return NULL;
- folio = (struct folio *)alloc_contig_frozen_pages(1 << order, gfp_mask,
- nid, nodemask);
+ folio = (struct folio *)alloc_contig_frozen_pages_user(1 << order,
+ gfp_mask,
+ nid, nodemask,
+ addr);
return folio;
}
#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE || !CONFIG_CONTIG_ALLOC */
static struct folio *alloc_gigantic_frozen_folio(int order, gfp_t gfp_mask, int nid,
- nodemask_t *nodemask)
+ nodemask_t *nodemask, unsigned long addr)
{
return NULL;
}
@@ -1862,7 +1864,8 @@ static struct folio *only_alloc_fresh_hugetlb_folio(struct hstate *h,
nid = numa_mem_id();
if (order_is_gigantic(order))
- folio = alloc_gigantic_frozen_folio(order, gfp_mask, nid, nmask);
+ folio = alloc_gigantic_frozen_folio(order, gfp_mask, nid, nmask,
+ addr);
else
folio = alloc_buddy_frozen_folio(order, gfp_mask, nid, nmask,
node_alloc_noretry, addr);
--
MST
^ permalink raw reply related
* [PATCH v8 08/37] mm: add alloc_contig_frozen_pages_user for cache-friendly zeroing
From: Michael S. Tsirkin @ 2026-05-20 22:21 UTC (permalink / raw)
To: linux-kernel
Cc: David Hildenbrand (Arm), Jason Wang, Xuan Zhuo,
Eugenio Pérez, Muchun Song, Oscar Salvador, Andrew Morton,
Lorenzo Stoakes, Liam R. Howlett, Vlastimil Babka, Mike Rapoport,
Suren Baghdasaryan, Michal Hocko, Brendan Jackman,
Johannes Weiner, Zi Yan, Baolin Wang, Nico Pache, Ryan Roberts,
Dev Jain, Barry Song, Lance Yang, Hugh Dickins, Matthew Brost,
Joshua Hahn, Rakie Kim, Byungchul Park, Gregory Price, Ying Huang,
Alistair Popple, Christoph Lameter, David Rientjes,
Roman Gushchin, Harry Yoo, Axel Rasmussen, Yuanchu Xie, Wei Xu,
Chris Li, Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He,
virtualization, linux-mm, Andrea Arcangeli
In-Reply-To: <cover.1779315441.git.mst@redhat.com>
Add a _user variant of alloc_contig_frozen_pages that accepts a user_addr
parameter for cache-friendly zeroing of contiguous allocations.
No functional change; all existing callers continue to pass
USER_ADDR_NONE.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
---
include/linux/gfp.h | 6 ++++++
mm/page_alloc.c | 32 +++++++++++++++++++++++++-------
2 files changed, 31 insertions(+), 7 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index ee35c5367abc..73109d4e31a4 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -453,6 +453,12 @@ struct page *alloc_contig_frozen_pages_noprof(unsigned long nr_pages,
#define alloc_contig_frozen_pages(...) \
alloc_hooks(alloc_contig_frozen_pages_noprof(__VA_ARGS__))
+struct page *alloc_contig_frozen_pages_user_noprof(unsigned long nr_pages,
+ gfp_t gfp_mask, int nid, nodemask_t *nodemask,
+ unsigned long user_addr);
+#define alloc_contig_frozen_pages_user(...) \
+ alloc_hooks(alloc_contig_frozen_pages_user_noprof(__VA_ARGS__))
+
struct page *alloc_contig_pages_noprof(unsigned long nr_pages, gfp_t gfp_mask,
int nid, nodemask_t *nodemask);
#define alloc_contig_pages(...) \
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b96c9892f6c6..b725a3b59835 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6999,8 +6999,9 @@ static void __free_contig_frozen_range(unsigned long pfn, unsigned long nr_pages
*
* Return: zero on success or negative error code.
*/
-int alloc_contig_frozen_range_noprof(unsigned long start, unsigned long end,
- acr_flags_t alloc_flags, gfp_t gfp_mask)
+static int __alloc_contig_frozen_range(unsigned long start, unsigned long end,
+ acr_flags_t alloc_flags, gfp_t gfp_mask,
+ unsigned long user_addr)
{
const unsigned int order = ilog2(end - start);
unsigned long outer_start, outer_end;
@@ -7127,7 +7128,7 @@ int alloc_contig_frozen_range_noprof(unsigned long start, unsigned long end,
struct page *head = pfn_to_page(start);
check_new_pages(head, order);
- prep_new_page(head, order, gfp_mask, 0, USER_ADDR_NONE);
+ prep_new_page(head, order, gfp_mask, 0, user_addr);
} else {
ret = -EINVAL;
WARN(true, "PFN range: requested [%lu, %lu), allocated [%lu, %lu)\n",
@@ -7137,6 +7138,13 @@ int alloc_contig_frozen_range_noprof(unsigned long start, unsigned long end,
undo_isolate_page_range(start, end);
return ret;
}
+
+int alloc_contig_frozen_range_noprof(unsigned long start, unsigned long end,
+ acr_flags_t alloc_flags, gfp_t gfp_mask)
+{
+ return __alloc_contig_frozen_range(start, end, alloc_flags, gfp_mask,
+ USER_ADDR_NONE);
+}
EXPORT_SYMBOL(alloc_contig_frozen_range_noprof);
/**
@@ -7255,8 +7263,9 @@ static bool zone_spans_last_pfn(const struct zone *zone,
*
* Return: pointer to contiguous frozen pages on success, or NULL if not successful.
*/
-struct page *alloc_contig_frozen_pages_noprof(unsigned long nr_pages,
- gfp_t gfp_mask, int nid, nodemask_t *nodemask)
+struct page *alloc_contig_frozen_pages_user_noprof(unsigned long nr_pages,
+ gfp_t gfp_mask, int nid, nodemask_t *nodemask,
+ unsigned long user_addr)
{
unsigned long ret, pfn, flags;
struct zonelist *zonelist;
@@ -7284,10 +7293,11 @@ struct page *alloc_contig_frozen_pages_noprof(unsigned long nr_pages,
* win the race and cause allocation to fail.
*/
spin_unlock_irqrestore(&zone->lock, flags);
- ret = alloc_contig_frozen_range_noprof(pfn,
+ ret = __alloc_contig_frozen_range(pfn,
pfn + nr_pages,
ACR_FLAGS_NONE,
- gfp_mask);
+ gfp_mask,
+ user_addr);
if (!ret)
return pfn_to_page(pfn);
spin_lock_irqsave(&zone->lock, flags);
@@ -7309,6 +7319,14 @@ struct page *alloc_contig_frozen_pages_noprof(unsigned long nr_pages,
}
return NULL;
}
+EXPORT_SYMBOL(alloc_contig_frozen_pages_user_noprof);
+
+struct page *alloc_contig_frozen_pages_noprof(unsigned long nr_pages,
+ gfp_t gfp_mask, int nid, nodemask_t *nodemask)
+{
+ return alloc_contig_frozen_pages_user_noprof(nr_pages, gfp_mask, nid,
+ nodemask, USER_ADDR_NONE);
+}
EXPORT_SYMBOL(alloc_contig_frozen_pages_noprof);
/**
--
MST
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