* + revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch added to mm-hotfixes-unstable branch
@ 2026-05-19 0:31 Andrew Morton
2026-05-19 5:10 ` Byungchul Park
0 siblings, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2026-05-19 0:31 UTC (permalink / raw)
To: mm-commits, ziy, willy, vbabka, toke, tariqt, surenb, sdf, saeedm,
rppt, pabeni, mhocko, mbloch, ljs, liam, leon, kuba,
john.fastabend, jackmanb, ilias.apalodimas, horms, hawk, harry,
hannes, edumazet, dtatulea, david, davem, baolin.wang, ast,
asml.silence, byungchul, akpm
The patch titled
Subject: Revert "mm: introduce a new page type for page pool in page type"
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Byungchul Park <byungchul@sk.com>
Subject: Revert "mm: introduce a new page type for page pool in page type"
Date: Fri, 15 May 2026 12:47:01 +0900
This reverts commit db359fccf212 ("mm: introduce a new page type for page
pool in page type") and a part of 735a309b4bfb9e ("net: add net_iov_init()
and use it > to initialize ->page_type").
Netpp page_type'ed pages might be used in mapping so as to use @_mapcount.
However, since @page_type and @_mapcount are union'ed in struct page,
these two can't be used at the same time. Revert the commit introducing
page_type for Netpp for now.
The patch will be retried once @page_type and @_mapcount get allowed to be
used at the same time.
The revert also includes removal of @page_type initialization part
introduced by commit 735a309b4bfb9e ("net: add net_iov_init() and use it
to initialize ->page_type"), which will be restored on the retry.
Link: https://lore.kernel.org/20260515034701.17027-1-byungchul@sk.com
Fixes: db359fccf212 ("mm: introduce a new page type for page pool in page type")
Signed-off-by: Byungchul Park <byungchul@sk.com>
Reported-by: Dragos Tatulea <dtatulea@nvidia.com>
Closes: https://lore.kernel.org/all/982b9bc1-0a0a-4fc5-8e3a-3672db2b29a1@nvidia.com
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Harry Yoo (Oracle) <harry@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Mark Bloch <mbloch@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Saeed Mahameed <saeedm@nvidia.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tariq Toukan <tariqt@nvidia.com>
Cc: Toke Hoiland-Jorgensen <toke@redhat.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 2
include/linux/mm.h | 27 +++++++++++--
include/linux/page-flags.h | 6 --
include/net/netmem.h | 19 ---------
mm/page_alloc.c | 13 +-----
net/core/netmem_priv.h | 23 ++++++-----
net/core/page_pool.c | 24 -----------
7 files changed, 46 insertions(+), 68 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
+++ a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
@@ -708,7 +708,7 @@ static void mlx5e_free_xdpsq_desc(struct
xdpi = mlx5e_xdpi_fifo_pop(xdpi_fifo);
page = xdpi.page.page;
- /* No need to check PageNetpp() as we
+ /* No need to check page_pool_page_is_pp() as we
* know this is a page_pool page.
*/
page_pool_recycle_direct(pp_page_to_nmdesc(page)->pp,
--- a/include/linux/mm.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
+++ a/include/linux/mm.h
@@ -5174,9 +5174,10 @@ int arch_lock_shadow_stack_status(struct
* DMA mapping IDs for page_pool
*
* When DMA-mapping a page, page_pool allocates an ID (from an xarray) and
- * stashes it in the upper bits of page->pp_magic. Non-PP pages can have
- * arbitrary kernel pointers stored in the same field as pp_magic (since
- * it overlaps with page->lru.next), so we must ensure that we cannot
+ * stashes it in the upper bits of page->pp_magic. We always want to be able to
+ * unambiguously identify page pool pages (using page_pool_page_is_pp()). Non-PP
+ * pages can have arbitrary kernel pointers stored in the same field as pp_magic
+ * (since it overlaps with page->lru.next), so we must ensure that we cannot
* mistake a valid kernel pointer with any of the values we write into this
* field.
*
@@ -5211,6 +5212,26 @@ int arch_lock_shadow_stack_status(struct
#define PP_DMA_INDEX_MASK GENMASK(PP_DMA_INDEX_BITS + PP_DMA_INDEX_SHIFT - 1, \
PP_DMA_INDEX_SHIFT)
+/* Mask used for checking in page_pool_page_is_pp() below. page->pp_magic is
+ * OR'ed with PP_SIGNATURE after the allocation in order to preserve bit 0 for
+ * the head page of compound page and bit 1 for pfmemalloc page, as well as the
+ * bits used for the DMA index. page_is_pfmemalloc() is checked in
+ * __page_pool_put_page() to avoid recycling the pfmemalloc page.
+ */
+#define PP_MAGIC_MASK ~(PP_DMA_INDEX_MASK | 0x3UL)
+
+#ifdef CONFIG_PAGE_POOL
+static inline bool page_pool_page_is_pp(const struct page *page)
+{
+ return (page->pp_magic & PP_MAGIC_MASK) == PP_SIGNATURE;
+}
+#else
+static inline bool page_pool_page_is_pp(const struct page *page)
+{
+ return false;
+}
+#endif
+
#define PAGE_SNAPSHOT_FAITHFUL (1 << 0)
#define PAGE_SNAPSHOT_PG_BUDDY (1 << 1)
#define PAGE_SNAPSHOT_PG_IDLE (1 << 2)
--- a/include/linux/page-flags.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
+++ a/include/linux/page-flags.h
@@ -923,7 +923,6 @@ enum pagetype {
PGTY_zsmalloc = 0xf6,
PGTY_unaccepted = 0xf7,
PGTY_large_kmalloc = 0xf8,
- PGTY_netpp = 0xf9,
PGTY_mapcount_underflow = 0xff
};
@@ -1056,11 +1055,6 @@ PAGE_TYPE_OPS(Zsmalloc, zsmalloc, zsmall
PAGE_TYPE_OPS(Unaccepted, unaccepted, unaccepted)
PAGE_TYPE_OPS(LargeKmalloc, large_kmalloc, large_kmalloc)
-/*
- * Marks page_pool allocated pages.
- */
-PAGE_TYPE_OPS(Netpp, netpp, netpp)
-
/**
* PageHuge - Determine if the page belongs to hugetlbfs
* @page: The page to test.
--- a/include/net/netmem.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
+++ a/include/net/netmem.h
@@ -94,20 +94,10 @@ enum net_iov_type {
*/
struct net_iov {
struct netmem_desc desc;
- unsigned int page_type;
enum net_iov_type type;
struct net_iov_area *owner;
};
-/* Make sure 'the offset of page_type in struct page == the offset of
- * type in struct net_iov'.
- */
-#define NET_IOV_ASSERT_OFFSET(pg, iov) \
- static_assert(offsetof(struct page, pg) == \
- offsetof(struct net_iov, iov))
-NET_IOV_ASSERT_OFFSET(page_type, page_type);
-#undef NET_IOV_ASSERT_OFFSET
-
struct net_iov_area {
/* Array of net_iovs for this area. */
struct net_iov *niovs;
@@ -127,11 +117,7 @@ static inline unsigned int net_iov_idx(c
return niov - net_iov_owner(niov)->niovs;
}
-/* Initialize a niov: stamp the owning area, the memory provider type,
- * and the page_type "no type" sentinel expected by the page-type API
- * (see PAGE_TYPE_OPS in <linux/page-flags.h>) so that
- * page_pool_set_pp_info() can later call __SetPageNetpp() on a niov
- * cast to struct page.
+/* Initialize a niov: stamp the owning area, the memory provider type.
*/
static inline void net_iov_init(struct net_iov *niov,
struct net_iov_area *owner,
@@ -139,7 +125,6 @@ static inline void net_iov_init(struct n
{
niov->owner = owner;
niov->type = type;
- niov->page_type = UINT_MAX;
}
/* netmem */
@@ -245,7 +230,7 @@ static inline unsigned long netmem_pfn_t
*/
#define pp_page_to_nmdesc(p) \
({ \
- DEBUG_NET_WARN_ON_ONCE(!PageNetpp(p)); \
+ DEBUG_NET_WARN_ON_ONCE(!page_pool_page_is_pp(p)); \
__pp_page_to_nmdesc(p); \
})
--- a/mm/page_alloc.c~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
+++ a/mm/page_alloc.c
@@ -1035,6 +1035,7 @@ static inline bool page_expected_state(s
#ifdef CONFIG_MEMCG
page->memcg_data |
#endif
+ page_pool_page_is_pp(page) |
(page->flags.f & check_flags)))
return false;
@@ -1061,6 +1062,8 @@ static const char *page_bad_reason(struc
if (unlikely(page->memcg_data))
bad_reason = "page still charged to cgroup";
#endif
+ if (unlikely(page_pool_page_is_pp(page)))
+ bad_reason = "page_pool leak";
return bad_reason;
}
@@ -1377,17 +1380,9 @@ __always_inline bool __free_pages_prepar
mod_mthp_stat(order, MTHP_STAT_NR_ANON, -1);
folio->mapping = NULL;
}
- if (unlikely(page_has_type(page))) {
- /* networking expects to clear its page type before releasing */
- if (is_check_pages_enabled()) {
- if (unlikely(PageNetpp(page))) {
- bad_page(page, "page_pool leak");
- return false;
- }
- }
+ if (unlikely(page_has_type(page)))
/* Reset the page_type (which overlays _mapcount) */
page->page_type = UINT_MAX;
- }
if (is_check_pages_enabled()) {
if (free_page_is_bad(page))
--- a/net/core/netmem_priv.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
+++ a/net/core/netmem_priv.h
@@ -8,18 +8,21 @@ static inline unsigned long netmem_get_p
return netmem_to_nmdesc(netmem)->pp_magic & ~PP_DMA_INDEX_MASK;
}
-static inline bool netmem_is_pp(netmem_ref netmem)
+static inline void netmem_or_pp_magic(netmem_ref netmem, unsigned long pp_magic)
+{
+ netmem_to_nmdesc(netmem)->pp_magic |= pp_magic;
+}
+
+static inline void netmem_clear_pp_magic(netmem_ref netmem)
{
- struct page *page;
+ WARN_ON_ONCE(netmem_to_nmdesc(netmem)->pp_magic & PP_DMA_INDEX_MASK);
- /* XXX: Now that the offset of page_type is shared between
- * struct page and net_iov, just cast the netmem to struct page
- * unconditionally by clearing NET_IOV if any, no matter whether
- * it comes from struct net_iov or struct page. This should be
- * adjusted once the offset is no longer shared.
- */
- page = (struct page *)((__force unsigned long)netmem & ~NET_IOV);
- return PageNetpp(page);
+ netmem_to_nmdesc(netmem)->pp_magic = 0;
+}
+
+static inline bool netmem_is_pp(netmem_ref netmem)
+{
+ return (netmem_get_pp_magic(netmem) & PP_MAGIC_MASK) == PP_SIGNATURE;
}
static inline void netmem_set_pp(netmem_ref netmem, struct page_pool *pool)
--- a/net/core/page_pool.c~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
+++ a/net/core/page_pool.c
@@ -707,18 +707,8 @@ s32 page_pool_inflight(const struct page
void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem)
{
- struct page *page;
-
netmem_set_pp(netmem, pool);
-
- /* XXX: Now that the offset of page_type is shared between
- * struct page and net_iov, just cast the netmem to struct page
- * unconditionally by clearing NET_IOV if any, no matter whether
- * it comes from struct net_iov or struct page. This should be
- * adjusted once the offset is no longer shared.
- */
- page = (struct page *)((__force unsigned long)netmem & ~NET_IOV);
- __SetPageNetpp(page);
+ netmem_or_pp_magic(netmem, PP_SIGNATURE);
/* Ensuring all pages have been split into one fragment initially:
* page_pool_set_pp_info() is only called once for every page when it
@@ -733,17 +723,7 @@ void page_pool_set_pp_info(struct page_p
void page_pool_clear_pp_info(netmem_ref netmem)
{
- struct page *page;
-
- /* XXX: Now that the offset of page_type is shared between
- * struct page and net_iov, just cast the netmem to struct page
- * unconditionally by clearing NET_IOV if any, no matter whether
- * it comes from struct net_iov or struct page. This should be
- * adjusted once the offset is no longer shared.
- */
- page = (struct page *)((__force unsigned long)netmem & ~NET_IOV);
- __ClearPageNetpp(page);
-
+ netmem_clear_pp_magic(netmem);
netmem_set_pp(netmem, NULL);
}
_
Patches currently in -mm which might be from byungchul@sk.com are
revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: + revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch added to mm-hotfixes-unstable branch
2026-05-19 0:31 + revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch added to mm-hotfixes-unstable branch Andrew Morton
@ 2026-05-19 5:10 ` Byungchul Park
2026-05-19 6:42 ` Byungchul Park
0 siblings, 1 reply; 4+ messages in thread
From: Byungchul Park @ 2026-05-19 5:10 UTC (permalink / raw)
To: Andrew Morton
Cc: mm-commits, ziy, willy, vbabka, toke, tariqt, surenb, sdf, saeedm,
rppt, pabeni, mhocko, mbloch, ljs, liam, leon, kuba,
john.fastabend, jackmanb, ilias.apalodimas, horms, hawk, harry,
hannes, edumazet, dtatulea, david, davem, baolin.wang, ast,
asml.silence, kernel_team
On Mon, May 18, 2026 at 05:31:24PM -0700, Andrew Morton wrote:
> The patch titled
> Subject: Revert "mm: introduce a new page type for page pool in page type"
> has been added to the -mm mm-hotfixes-unstable branch. Its filename is
> revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch
>
> This patch will shortly appear at
> https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch
>
> This patch will later appear in the mm-hotfixes-unstable branch at
> git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
>
> Before you just go and hit "reply", please:
> a) Consider who else should be cc'ed
> b) Prefer to cc a suitable mailing list as well
> c) Ideally: find the original patch on the mailing list and do a
> reply-to-all to that, adding suitable additional cc's
>
> *** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
>
> The -mm tree is included into linux-next via various
> branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> and is updated there most days
>
> ------------------------------------------------------
> From: Byungchul Park <byungchul@sk.com>
> Subject: Revert "mm: introduce a new page type for page pool in page type"
> Date: Fri, 15 May 2026 12:47:01 +0900
>
> This reverts commit db359fccf212 ("mm: introduce a new page type for page
> pool in page type") and a part of 735a309b4bfb9e ("net: add net_iov_init()
> and use it > to initialize ->page_type").
^
Check this out, Andrew.
Byungchul
> Netpp page_type'ed pages might be used in mapping so as to use @_mapcount.
> However, since @page_type and @_mapcount are union'ed in struct page,
> these two can't be used at the same time. Revert the commit introducing
> page_type for Netpp for now.
>
> The patch will be retried once @page_type and @_mapcount get allowed to be
> used at the same time.
>
> The revert also includes removal of @page_type initialization part
> introduced by commit 735a309b4bfb9e ("net: add net_iov_init() and use it
> to initialize ->page_type"), which will be restored on the retry.
>
> Link: https://lore.kernel.org/20260515034701.17027-1-byungchul@sk.com
> Fixes: db359fccf212 ("mm: introduce a new page type for page pool in page type")
> Signed-off-by: Byungchul Park <byungchul@sk.com>
> Reported-by: Dragos Tatulea <dtatulea@nvidia.com>
> Closes: https://lore.kernel.org/all/982b9bc1-0a0a-4fc5-8e3a-3672db2b29a1@nvidia.com
> Acked-by: Jakub Kicinski <kuba@kernel.org>
> Acked-by: David Hildenbrand (Arm) <david@kernel.org>
> Acked-by: Harry Yoo (Oracle) <harry@kernel.org>
> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
> Cc: Brendan Jackman <jackmanb@google.com>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> Cc: Jesper Dangaard Brouer <hawk@kernel.org>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: John Fastabend <john.fastabend@gmail.com>
> Cc: Leon Romanovsky <leon@kernel.org>
> Cc: Liam R. Howlett <liam@infradead.org>
> Cc: Mark Bloch <mbloch@nvidia.com>
> Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Mike Rapoport <rppt@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: Pavel Begunkov <asml.silence@gmail.com>
> Cc: Saeed Mahameed <saeedm@nvidia.com>
> Cc: Simon Horman <horms@kernel.org>
> Cc: Stanislav Fomichev <sdf@fomichev.me>
> Cc: Suren Baghdasaryan <surenb@google.com>
> Cc: Tariq Toukan <tariqt@nvidia.com>
> Cc: Toke Hoiland-Jorgensen <toke@redhat.com>
> Cc: Vlastimil Babka <vbabka@kernel.org>
> Cc: Zi Yan <ziy@nvidia.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
> drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 2
> include/linux/mm.h | 27 +++++++++++--
> include/linux/page-flags.h | 6 --
> include/net/netmem.h | 19 ---------
> mm/page_alloc.c | 13 +-----
> net/core/netmem_priv.h | 23 ++++++-----
> net/core/page_pool.c | 24 -----------
> 7 files changed, 46 insertions(+), 68 deletions(-)
>
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> +++ a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
> @@ -708,7 +708,7 @@ static void mlx5e_free_xdpsq_desc(struct
> xdpi = mlx5e_xdpi_fifo_pop(xdpi_fifo);
> page = xdpi.page.page;
>
> - /* No need to check PageNetpp() as we
> + /* No need to check page_pool_page_is_pp() as we
> * know this is a page_pool page.
> */
> page_pool_recycle_direct(pp_page_to_nmdesc(page)->pp,
> --- a/include/linux/mm.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> +++ a/include/linux/mm.h
> @@ -5174,9 +5174,10 @@ int arch_lock_shadow_stack_status(struct
> * DMA mapping IDs for page_pool
> *
> * When DMA-mapping a page, page_pool allocates an ID (from an xarray) and
> - * stashes it in the upper bits of page->pp_magic. Non-PP pages can have
> - * arbitrary kernel pointers stored in the same field as pp_magic (since
> - * it overlaps with page->lru.next), so we must ensure that we cannot
> + * stashes it in the upper bits of page->pp_magic. We always want to be able to
> + * unambiguously identify page pool pages (using page_pool_page_is_pp()). Non-PP
> + * pages can have arbitrary kernel pointers stored in the same field as pp_magic
> + * (since it overlaps with page->lru.next), so we must ensure that we cannot
> * mistake a valid kernel pointer with any of the values we write into this
> * field.
> *
> @@ -5211,6 +5212,26 @@ int arch_lock_shadow_stack_status(struct
> #define PP_DMA_INDEX_MASK GENMASK(PP_DMA_INDEX_BITS + PP_DMA_INDEX_SHIFT - 1, \
> PP_DMA_INDEX_SHIFT)
>
> +/* Mask used for checking in page_pool_page_is_pp() below. page->pp_magic is
> + * OR'ed with PP_SIGNATURE after the allocation in order to preserve bit 0 for
> + * the head page of compound page and bit 1 for pfmemalloc page, as well as the
> + * bits used for the DMA index. page_is_pfmemalloc() is checked in
> + * __page_pool_put_page() to avoid recycling the pfmemalloc page.
> + */
> +#define PP_MAGIC_MASK ~(PP_DMA_INDEX_MASK | 0x3UL)
> +
> +#ifdef CONFIG_PAGE_POOL
> +static inline bool page_pool_page_is_pp(const struct page *page)
> +{
> + return (page->pp_magic & PP_MAGIC_MASK) == PP_SIGNATURE;
> +}
> +#else
> +static inline bool page_pool_page_is_pp(const struct page *page)
> +{
> + return false;
> +}
> +#endif
> +
> #define PAGE_SNAPSHOT_FAITHFUL (1 << 0)
> #define PAGE_SNAPSHOT_PG_BUDDY (1 << 1)
> #define PAGE_SNAPSHOT_PG_IDLE (1 << 2)
> --- a/include/linux/page-flags.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> +++ a/include/linux/page-flags.h
> @@ -923,7 +923,6 @@ enum pagetype {
> PGTY_zsmalloc = 0xf6,
> PGTY_unaccepted = 0xf7,
> PGTY_large_kmalloc = 0xf8,
> - PGTY_netpp = 0xf9,
>
> PGTY_mapcount_underflow = 0xff
> };
> @@ -1056,11 +1055,6 @@ PAGE_TYPE_OPS(Zsmalloc, zsmalloc, zsmall
> PAGE_TYPE_OPS(Unaccepted, unaccepted, unaccepted)
> PAGE_TYPE_OPS(LargeKmalloc, large_kmalloc, large_kmalloc)
>
> -/*
> - * Marks page_pool allocated pages.
> - */
> -PAGE_TYPE_OPS(Netpp, netpp, netpp)
> -
> /**
> * PageHuge - Determine if the page belongs to hugetlbfs
> * @page: The page to test.
> --- a/include/net/netmem.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> +++ a/include/net/netmem.h
> @@ -94,20 +94,10 @@ enum net_iov_type {
> */
> struct net_iov {
> struct netmem_desc desc;
> - unsigned int page_type;
> enum net_iov_type type;
> struct net_iov_area *owner;
> };
>
> -/* Make sure 'the offset of page_type in struct page == the offset of
> - * type in struct net_iov'.
> - */
> -#define NET_IOV_ASSERT_OFFSET(pg, iov) \
> - static_assert(offsetof(struct page, pg) == \
> - offsetof(struct net_iov, iov))
> -NET_IOV_ASSERT_OFFSET(page_type, page_type);
> -#undef NET_IOV_ASSERT_OFFSET
> -
> struct net_iov_area {
> /* Array of net_iovs for this area. */
> struct net_iov *niovs;
> @@ -127,11 +117,7 @@ static inline unsigned int net_iov_idx(c
> return niov - net_iov_owner(niov)->niovs;
> }
>
> -/* Initialize a niov: stamp the owning area, the memory provider type,
> - * and the page_type "no type" sentinel expected by the page-type API
> - * (see PAGE_TYPE_OPS in <linux/page-flags.h>) so that
> - * page_pool_set_pp_info() can later call __SetPageNetpp() on a niov
> - * cast to struct page.
> +/* Initialize a niov: stamp the owning area, the memory provider type.
> */
> static inline void net_iov_init(struct net_iov *niov,
> struct net_iov_area *owner,
> @@ -139,7 +125,6 @@ static inline void net_iov_init(struct n
> {
> niov->owner = owner;
> niov->type = type;
> - niov->page_type = UINT_MAX;
> }
>
> /* netmem */
> @@ -245,7 +230,7 @@ static inline unsigned long netmem_pfn_t
> */
> #define pp_page_to_nmdesc(p) \
> ({ \
> - DEBUG_NET_WARN_ON_ONCE(!PageNetpp(p)); \
> + DEBUG_NET_WARN_ON_ONCE(!page_pool_page_is_pp(p)); \
> __pp_page_to_nmdesc(p); \
> })
>
> --- a/mm/page_alloc.c~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> +++ a/mm/page_alloc.c
> @@ -1035,6 +1035,7 @@ static inline bool page_expected_state(s
> #ifdef CONFIG_MEMCG
> page->memcg_data |
> #endif
> + page_pool_page_is_pp(page) |
> (page->flags.f & check_flags)))
> return false;
>
> @@ -1061,6 +1062,8 @@ static const char *page_bad_reason(struc
> if (unlikely(page->memcg_data))
> bad_reason = "page still charged to cgroup";
> #endif
> + if (unlikely(page_pool_page_is_pp(page)))
> + bad_reason = "page_pool leak";
> return bad_reason;
> }
>
> @@ -1377,17 +1380,9 @@ __always_inline bool __free_pages_prepar
> mod_mthp_stat(order, MTHP_STAT_NR_ANON, -1);
> folio->mapping = NULL;
> }
> - if (unlikely(page_has_type(page))) {
> - /* networking expects to clear its page type before releasing */
> - if (is_check_pages_enabled()) {
> - if (unlikely(PageNetpp(page))) {
> - bad_page(page, "page_pool leak");
> - return false;
> - }
> - }
> + if (unlikely(page_has_type(page)))
> /* Reset the page_type (which overlays _mapcount) */
> page->page_type = UINT_MAX;
> - }
>
> if (is_check_pages_enabled()) {
> if (free_page_is_bad(page))
> --- a/net/core/netmem_priv.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> +++ a/net/core/netmem_priv.h
> @@ -8,18 +8,21 @@ static inline unsigned long netmem_get_p
> return netmem_to_nmdesc(netmem)->pp_magic & ~PP_DMA_INDEX_MASK;
> }
>
> -static inline bool netmem_is_pp(netmem_ref netmem)
> +static inline void netmem_or_pp_magic(netmem_ref netmem, unsigned long pp_magic)
> +{
> + netmem_to_nmdesc(netmem)->pp_magic |= pp_magic;
> +}
> +
> +static inline void netmem_clear_pp_magic(netmem_ref netmem)
> {
> - struct page *page;
> + WARN_ON_ONCE(netmem_to_nmdesc(netmem)->pp_magic & PP_DMA_INDEX_MASK);
>
> - /* XXX: Now that the offset of page_type is shared between
> - * struct page and net_iov, just cast the netmem to struct page
> - * unconditionally by clearing NET_IOV if any, no matter whether
> - * it comes from struct net_iov or struct page. This should be
> - * adjusted once the offset is no longer shared.
> - */
> - page = (struct page *)((__force unsigned long)netmem & ~NET_IOV);
> - return PageNetpp(page);
> + netmem_to_nmdesc(netmem)->pp_magic = 0;
> +}
> +
> +static inline bool netmem_is_pp(netmem_ref netmem)
> +{
> + return (netmem_get_pp_magic(netmem) & PP_MAGIC_MASK) == PP_SIGNATURE;
> }
>
> static inline void netmem_set_pp(netmem_ref netmem, struct page_pool *pool)
> --- a/net/core/page_pool.c~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> +++ a/net/core/page_pool.c
> @@ -707,18 +707,8 @@ s32 page_pool_inflight(const struct page
>
> void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem)
> {
> - struct page *page;
> -
> netmem_set_pp(netmem, pool);
> -
> - /* XXX: Now that the offset of page_type is shared between
> - * struct page and net_iov, just cast the netmem to struct page
> - * unconditionally by clearing NET_IOV if any, no matter whether
> - * it comes from struct net_iov or struct page. This should be
> - * adjusted once the offset is no longer shared.
> - */
> - page = (struct page *)((__force unsigned long)netmem & ~NET_IOV);
> - __SetPageNetpp(page);
> + netmem_or_pp_magic(netmem, PP_SIGNATURE);
>
> /* Ensuring all pages have been split into one fragment initially:
> * page_pool_set_pp_info() is only called once for every page when it
> @@ -733,17 +723,7 @@ void page_pool_set_pp_info(struct page_p
>
> void page_pool_clear_pp_info(netmem_ref netmem)
> {
> - struct page *page;
> -
> - /* XXX: Now that the offset of page_type is shared between
> - * struct page and net_iov, just cast the netmem to struct page
> - * unconditionally by clearing NET_IOV if any, no matter whether
> - * it comes from struct net_iov or struct page. This should be
> - * adjusted once the offset is no longer shared.
> - */
> - page = (struct page *)((__force unsigned long)netmem & ~NET_IOV);
> - __ClearPageNetpp(page);
> -
> + netmem_clear_pp_magic(netmem);
> netmem_set_pp(netmem, NULL);
> }
>
> _
>
> Patches currently in -mm which might be from byungchul@sk.com are
>
> revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: + revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch added to mm-hotfixes-unstable branch
2026-05-19 5:10 ` Byungchul Park
@ 2026-05-19 6:42 ` Byungchul Park
2026-05-19 15:25 ` Andrew Morton
0 siblings, 1 reply; 4+ messages in thread
From: Byungchul Park @ 2026-05-19 6:42 UTC (permalink / raw)
To: Andrew Morton
Cc: mm-commits, ziy, willy, vbabka, toke, tariqt, surenb, sdf, saeedm,
rppt, pabeni, mhocko, mbloch, ljs, liam, leon, kuba,
john.fastabend, jackmanb, ilias.apalodimas, horms, hawk, harry,
hannes, edumazet, dtatulea, david, davem, baolin.wang, ast,
asml.silence, kernel_team
On Tue, May 19, 2026 at 02:10:02PM +0900, Byungchul Park wrote:
> On Mon, May 18, 2026 at 05:31:24PM -0700, Andrew Morton wrote:
> > The patch titled
> > Subject: Revert "mm: introduce a new page type for page pool in page type"
> > has been added to the -mm mm-hotfixes-unstable branch. Its filename is
> > revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch
> >
> > This patch will shortly appear at
> > https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch
> >
> > This patch will later appear in the mm-hotfixes-unstable branch at
> > git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> >
> > Before you just go and hit "reply", please:
> > a) Consider who else should be cc'ed
> > b) Prefer to cc a suitable mailing list as well
> > c) Ideally: find the original patch on the mailing list and do a
> > reply-to-all to that, adding suitable additional cc's
> >
> > *** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
> >
> > The -mm tree is included into linux-next via various
> > branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> > and is updated there most days
> >
> > ------------------------------------------------------
> > From: Byungchul Park <byungchul@sk.com>
> > Subject: Revert "mm: introduce a new page type for page pool in page type"
> > Date: Fri, 15 May 2026 12:47:01 +0900
> >
> > This reverts commit db359fccf212 ("mm: introduce a new page type for page
> > pool in page type") and a part of 735a309b4bfb9e ("net: add net_iov_init()
> > and use it > to initialize ->page_type").
> ^
> Check this out, Andrew.
Hm.. I might have expressed that incorrectly in English. I just wanted
you to check the '>' wrongly added :)
Byungchul
>
> Byungchul
>
> > Netpp page_type'ed pages might be used in mapping so as to use @_mapcount.
> > However, since @page_type and @_mapcount are union'ed in struct page,
> > these two can't be used at the same time. Revert the commit introducing
> > page_type for Netpp for now.
> >
> > The patch will be retried once @page_type and @_mapcount get allowed to be
> > used at the same time.
> >
> > The revert also includes removal of @page_type initialization part
> > introduced by commit 735a309b4bfb9e ("net: add net_iov_init() and use it
> > to initialize ->page_type"), which will be restored on the retry.
> >
> > Link: https://lore.kernel.org/20260515034701.17027-1-byungchul@sk.com
> > Fixes: db359fccf212 ("mm: introduce a new page type for page pool in page type")
> > Signed-off-by: Byungchul Park <byungchul@sk.com>
> > Reported-by: Dragos Tatulea <dtatulea@nvidia.com>
> > Closes: https://lore.kernel.org/all/982b9bc1-0a0a-4fc5-8e3a-3672db2b29a1@nvidia.com
> > Acked-by: Jakub Kicinski <kuba@kernel.org>
> > Acked-by: David Hildenbrand (Arm) <david@kernel.org>
> > Acked-by: Harry Yoo (Oracle) <harry@kernel.org>
> > Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
> > Cc: Alexei Starovoitov <ast@kernel.org>
> > Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
> > Cc: Brendan Jackman <jackmanb@google.com>
> > Cc: David S. Miller <davem@davemloft.net>
> > Cc: Eric Dumazet <edumazet@google.com>
> > Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> > Cc: Jesper Dangaard Brouer <hawk@kernel.org>
> > Cc: Johannes Weiner <hannes@cmpxchg.org>
> > Cc: John Fastabend <john.fastabend@gmail.com>
> > Cc: Leon Romanovsky <leon@kernel.org>
> > Cc: Liam R. Howlett <liam@infradead.org>
> > Cc: Mark Bloch <mbloch@nvidia.com>
> > Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
> > Cc: Michal Hocko <mhocko@suse.com>
> > Cc: Mike Rapoport <rppt@kernel.org>
> > Cc: Paolo Abeni <pabeni@redhat.com>
> > Cc: Pavel Begunkov <asml.silence@gmail.com>
> > Cc: Saeed Mahameed <saeedm@nvidia.com>
> > Cc: Simon Horman <horms@kernel.org>
> > Cc: Stanislav Fomichev <sdf@fomichev.me>
> > Cc: Suren Baghdasaryan <surenb@google.com>
> > Cc: Tariq Toukan <tariqt@nvidia.com>
> > Cc: Toke Hoiland-Jorgensen <toke@redhat.com>
> > Cc: Vlastimil Babka <vbabka@kernel.org>
> > Cc: Zi Yan <ziy@nvidia.com>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > ---
> >
> > drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 2
> > include/linux/mm.h | 27 +++++++++++--
> > include/linux/page-flags.h | 6 --
> > include/net/netmem.h | 19 ---------
> > mm/page_alloc.c | 13 +-----
> > net/core/netmem_priv.h | 23 ++++++-----
> > net/core/page_pool.c | 24 -----------
> > 7 files changed, 46 insertions(+), 68 deletions(-)
> >
> > --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> > +++ a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
> > @@ -708,7 +708,7 @@ static void mlx5e_free_xdpsq_desc(struct
> > xdpi = mlx5e_xdpi_fifo_pop(xdpi_fifo);
> > page = xdpi.page.page;
> >
> > - /* No need to check PageNetpp() as we
> > + /* No need to check page_pool_page_is_pp() as we
> > * know this is a page_pool page.
> > */
> > page_pool_recycle_direct(pp_page_to_nmdesc(page)->pp,
> > --- a/include/linux/mm.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> > +++ a/include/linux/mm.h
> > @@ -5174,9 +5174,10 @@ int arch_lock_shadow_stack_status(struct
> > * DMA mapping IDs for page_pool
> > *
> > * When DMA-mapping a page, page_pool allocates an ID (from an xarray) and
> > - * stashes it in the upper bits of page->pp_magic. Non-PP pages can have
> > - * arbitrary kernel pointers stored in the same field as pp_magic (since
> > - * it overlaps with page->lru.next), so we must ensure that we cannot
> > + * stashes it in the upper bits of page->pp_magic. We always want to be able to
> > + * unambiguously identify page pool pages (using page_pool_page_is_pp()). Non-PP
> > + * pages can have arbitrary kernel pointers stored in the same field as pp_magic
> > + * (since it overlaps with page->lru.next), so we must ensure that we cannot
> > * mistake a valid kernel pointer with any of the values we write into this
> > * field.
> > *
> > @@ -5211,6 +5212,26 @@ int arch_lock_shadow_stack_status(struct
> > #define PP_DMA_INDEX_MASK GENMASK(PP_DMA_INDEX_BITS + PP_DMA_INDEX_SHIFT - 1, \
> > PP_DMA_INDEX_SHIFT)
> >
> > +/* Mask used for checking in page_pool_page_is_pp() below. page->pp_magic is
> > + * OR'ed with PP_SIGNATURE after the allocation in order to preserve bit 0 for
> > + * the head page of compound page and bit 1 for pfmemalloc page, as well as the
> > + * bits used for the DMA index. page_is_pfmemalloc() is checked in
> > + * __page_pool_put_page() to avoid recycling the pfmemalloc page.
> > + */
> > +#define PP_MAGIC_MASK ~(PP_DMA_INDEX_MASK | 0x3UL)
> > +
> > +#ifdef CONFIG_PAGE_POOL
> > +static inline bool page_pool_page_is_pp(const struct page *page)
> > +{
> > + return (page->pp_magic & PP_MAGIC_MASK) == PP_SIGNATURE;
> > +}
> > +#else
> > +static inline bool page_pool_page_is_pp(const struct page *page)
> > +{
> > + return false;
> > +}
> > +#endif
> > +
> > #define PAGE_SNAPSHOT_FAITHFUL (1 << 0)
> > #define PAGE_SNAPSHOT_PG_BUDDY (1 << 1)
> > #define PAGE_SNAPSHOT_PG_IDLE (1 << 2)
> > --- a/include/linux/page-flags.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> > +++ a/include/linux/page-flags.h
> > @@ -923,7 +923,6 @@ enum pagetype {
> > PGTY_zsmalloc = 0xf6,
> > PGTY_unaccepted = 0xf7,
> > PGTY_large_kmalloc = 0xf8,
> > - PGTY_netpp = 0xf9,
> >
> > PGTY_mapcount_underflow = 0xff
> > };
> > @@ -1056,11 +1055,6 @@ PAGE_TYPE_OPS(Zsmalloc, zsmalloc, zsmall
> > PAGE_TYPE_OPS(Unaccepted, unaccepted, unaccepted)
> > PAGE_TYPE_OPS(LargeKmalloc, large_kmalloc, large_kmalloc)
> >
> > -/*
> > - * Marks page_pool allocated pages.
> > - */
> > -PAGE_TYPE_OPS(Netpp, netpp, netpp)
> > -
> > /**
> > * PageHuge - Determine if the page belongs to hugetlbfs
> > * @page: The page to test.
> > --- a/include/net/netmem.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> > +++ a/include/net/netmem.h
> > @@ -94,20 +94,10 @@ enum net_iov_type {
> > */
> > struct net_iov {
> > struct netmem_desc desc;
> > - unsigned int page_type;
> > enum net_iov_type type;
> > struct net_iov_area *owner;
> > };
> >
> > -/* Make sure 'the offset of page_type in struct page == the offset of
> > - * type in struct net_iov'.
> > - */
> > -#define NET_IOV_ASSERT_OFFSET(pg, iov) \
> > - static_assert(offsetof(struct page, pg) == \
> > - offsetof(struct net_iov, iov))
> > -NET_IOV_ASSERT_OFFSET(page_type, page_type);
> > -#undef NET_IOV_ASSERT_OFFSET
> > -
> > struct net_iov_area {
> > /* Array of net_iovs for this area. */
> > struct net_iov *niovs;
> > @@ -127,11 +117,7 @@ static inline unsigned int net_iov_idx(c
> > return niov - net_iov_owner(niov)->niovs;
> > }
> >
> > -/* Initialize a niov: stamp the owning area, the memory provider type,
> > - * and the page_type "no type" sentinel expected by the page-type API
> > - * (see PAGE_TYPE_OPS in <linux/page-flags.h>) so that
> > - * page_pool_set_pp_info() can later call __SetPageNetpp() on a niov
> > - * cast to struct page.
> > +/* Initialize a niov: stamp the owning area, the memory provider type.
> > */
> > static inline void net_iov_init(struct net_iov *niov,
> > struct net_iov_area *owner,
> > @@ -139,7 +125,6 @@ static inline void net_iov_init(struct n
> > {
> > niov->owner = owner;
> > niov->type = type;
> > - niov->page_type = UINT_MAX;
> > }
> >
> > /* netmem */
> > @@ -245,7 +230,7 @@ static inline unsigned long netmem_pfn_t
> > */
> > #define pp_page_to_nmdesc(p) \
> > ({ \
> > - DEBUG_NET_WARN_ON_ONCE(!PageNetpp(p)); \
> > + DEBUG_NET_WARN_ON_ONCE(!page_pool_page_is_pp(p)); \
> > __pp_page_to_nmdesc(p); \
> > })
> >
> > --- a/mm/page_alloc.c~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> > +++ a/mm/page_alloc.c
> > @@ -1035,6 +1035,7 @@ static inline bool page_expected_state(s
> > #ifdef CONFIG_MEMCG
> > page->memcg_data |
> > #endif
> > + page_pool_page_is_pp(page) |
> > (page->flags.f & check_flags)))
> > return false;
> >
> > @@ -1061,6 +1062,8 @@ static const char *page_bad_reason(struc
> > if (unlikely(page->memcg_data))
> > bad_reason = "page still charged to cgroup";
> > #endif
> > + if (unlikely(page_pool_page_is_pp(page)))
> > + bad_reason = "page_pool leak";
> > return bad_reason;
> > }
> >
> > @@ -1377,17 +1380,9 @@ __always_inline bool __free_pages_prepar
> > mod_mthp_stat(order, MTHP_STAT_NR_ANON, -1);
> > folio->mapping = NULL;
> > }
> > - if (unlikely(page_has_type(page))) {
> > - /* networking expects to clear its page type before releasing */
> > - if (is_check_pages_enabled()) {
> > - if (unlikely(PageNetpp(page))) {
> > - bad_page(page, "page_pool leak");
> > - return false;
> > - }
> > - }
> > + if (unlikely(page_has_type(page)))
> > /* Reset the page_type (which overlays _mapcount) */
> > page->page_type = UINT_MAX;
> > - }
> >
> > if (is_check_pages_enabled()) {
> > if (free_page_is_bad(page))
> > --- a/net/core/netmem_priv.h~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> > +++ a/net/core/netmem_priv.h
> > @@ -8,18 +8,21 @@ static inline unsigned long netmem_get_p
> > return netmem_to_nmdesc(netmem)->pp_magic & ~PP_DMA_INDEX_MASK;
> > }
> >
> > -static inline bool netmem_is_pp(netmem_ref netmem)
> > +static inline void netmem_or_pp_magic(netmem_ref netmem, unsigned long pp_magic)
> > +{
> > + netmem_to_nmdesc(netmem)->pp_magic |= pp_magic;
> > +}
> > +
> > +static inline void netmem_clear_pp_magic(netmem_ref netmem)
> > {
> > - struct page *page;
> > + WARN_ON_ONCE(netmem_to_nmdesc(netmem)->pp_magic & PP_DMA_INDEX_MASK);
> >
> > - /* XXX: Now that the offset of page_type is shared between
> > - * struct page and net_iov, just cast the netmem to struct page
> > - * unconditionally by clearing NET_IOV if any, no matter whether
> > - * it comes from struct net_iov or struct page. This should be
> > - * adjusted once the offset is no longer shared.
> > - */
> > - page = (struct page *)((__force unsigned long)netmem & ~NET_IOV);
> > - return PageNetpp(page);
> > + netmem_to_nmdesc(netmem)->pp_magic = 0;
> > +}
> > +
> > +static inline bool netmem_is_pp(netmem_ref netmem)
> > +{
> > + return (netmem_get_pp_magic(netmem) & PP_MAGIC_MASK) == PP_SIGNATURE;
> > }
> >
> > static inline void netmem_set_pp(netmem_ref netmem, struct page_pool *pool)
> > --- a/net/core/page_pool.c~revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type
> > +++ a/net/core/page_pool.c
> > @@ -707,18 +707,8 @@ s32 page_pool_inflight(const struct page
> >
> > void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem)
> > {
> > - struct page *page;
> > -
> > netmem_set_pp(netmem, pool);
> > -
> > - /* XXX: Now that the offset of page_type is shared between
> > - * struct page and net_iov, just cast the netmem to struct page
> > - * unconditionally by clearing NET_IOV if any, no matter whether
> > - * it comes from struct net_iov or struct page. This should be
> > - * adjusted once the offset is no longer shared.
> > - */
> > - page = (struct page *)((__force unsigned long)netmem & ~NET_IOV);
> > - __SetPageNetpp(page);
> > + netmem_or_pp_magic(netmem, PP_SIGNATURE);
> >
> > /* Ensuring all pages have been split into one fragment initially:
> > * page_pool_set_pp_info() is only called once for every page when it
> > @@ -733,17 +723,7 @@ void page_pool_set_pp_info(struct page_p
> >
> > void page_pool_clear_pp_info(netmem_ref netmem)
> > {
> > - struct page *page;
> > -
> > - /* XXX: Now that the offset of page_type is shared between
> > - * struct page and net_iov, just cast the netmem to struct page
> > - * unconditionally by clearing NET_IOV if any, no matter whether
> > - * it comes from struct net_iov or struct page. This should be
> > - * adjusted once the offset is no longer shared.
> > - */
> > - page = (struct page *)((__force unsigned long)netmem & ~NET_IOV);
> > - __ClearPageNetpp(page);
> > -
> > + netmem_clear_pp_magic(netmem);
> > netmem_set_pp(netmem, NULL);
> > }
> >
> > _
> >
> > Patches currently in -mm which might be from byungchul@sk.com are
> >
> > revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: + revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch added to mm-hotfixes-unstable branch
2026-05-19 6:42 ` Byungchul Park
@ 2026-05-19 15:25 ` Andrew Morton
0 siblings, 0 replies; 4+ messages in thread
From: Andrew Morton @ 2026-05-19 15:25 UTC (permalink / raw)
To: Byungchul Park
Cc: mm-commits, ziy, willy, vbabka, toke, tariqt, surenb, sdf, saeedm,
rppt, pabeni, mhocko, mbloch, ljs, liam, leon, kuba,
john.fastabend, jackmanb, ilias.apalodimas, horms, hawk, harry,
hannes, edumazet, dtatulea, david, davem, baolin.wang, ast,
asml.silence, kernel_team
On Tue, 19 May 2026 15:42:59 +0900 Byungchul Park <byungchul@sk.com> wrote:
> > > This reverts commit db359fccf212 ("mm: introduce a new page type for page
> > > pool in page type") and a part of 735a309b4bfb9e ("net: add net_iov_init()
> > > and use it > to initialize ->page_type").
> > ^
> > Check this out, Andrew.
>
> Hm.. I might have expressed that incorrectly in English. I just wanted
> you to check the '>' wrongly added :)
yep, thanks, I understood ;)
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-05-19 15:25 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-05-19 0:31 + revert-mm-introduce-a-new-page-type-for-page-pool-in-page-type.patch added to mm-hotfixes-unstable branch Andrew Morton
2026-05-19 5:10 ` Byungchul Park
2026-05-19 6:42 ` Byungchul Park
2026-05-19 15:25 ` Andrew Morton
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