FAILED: patch "[PATCH] mm/gup: avoid an unnecessary allocation call for" failed to apply to 6.11-stable tree

FAILED: patch "[PATCH] mm/gup: avoid an unnecessary allocation call for" failed to apply to 6.11-stable tree

[gregkh]

The patch below does not apply to the 6.11-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.11.y
git checkout FETCH_HEAD
git cherry-pick -x 94efde1d15399f5c88e576923db9bcd422d217f2
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024111754-stamina-flyer-1e05@gregkh' --subject-prefix 'PATCH 6.11.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 94efde1d15399f5c88e576923db9bcd422d217f2 Mon Sep 17 00:00:00 2001
From: John Hubbard <jhubbard@nvidia.com>
Date: Mon, 4 Nov 2024 19:29:44 -0800
Subject: [PATCH] mm/gup: avoid an unnecessary allocation call for
 FOLL_LONGTERM cases

commit 53ba78de064b ("mm/gup: introduce
check_and_migrate_movable_folios()") created a new constraint on the
pin_user_pages*() API family: a potentially large internal allocation must
now occur, for FOLL_LONGTERM cases.

A user-visible consequence has now appeared: user space can no longer pin
more than 2GB of memory anymore on x86_64.  That's because, on a 4KB
PAGE_SIZE system, when user space tries to (indirectly, via a device
driver that calls pin_user_pages()) pin 2GB, this requires an allocation
of a folio pointers array of MAX_PAGE_ORDER size, which is the limit for
kmalloc().

In addition to the directly visible effect described above, there is also
the problem of adding an unnecessary allocation.  The **pages array
argument has already been allocated, and there is no need for a redundant
**folios array allocation in this case.

Fix this by avoiding the new allocation entirely.  This is done by
referring to either the original page[i] within **pages, or to the
associated folio.  Thanks to David Hildenbrand for suggesting this
approach and for providing the initial implementation (which I've tested
and adjusted slightly) as well.

[jhubbard@nvidia.com: whitespace tweak, per David]
  Link: https://lkml.kernel.org/r/131cf9c8-ebc0-4cbb-b722-22fa8527bf3c@nvidia.com
[jhubbard@nvidia.com: bypass pofs_get_folio(), per Oscar]
  Link: https://lkml.kernel.org/r/c1587c7f-9155-45be-bd62-1e36c0dd6923@nvidia.com
Link: https://lkml.kernel.org/r/20241105032944.141488-2-jhubbard@nvidia.com
Fixes: 53ba78de064b ("mm/gup: introduce check_and_migrate_movable_folios()")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Junxiao Chang <junxiao.chang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/gup.c b/mm/gup.c
index 4637dab7b54f..ad0c8922dac3 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2273,20 +2273,57 @@ struct page *get_dump_page(unsigned long addr)
 #endif /* CONFIG_ELF_CORE */
 
 #ifdef CONFIG_MIGRATION
+
+/*
+ * An array of either pages or folios ("pofs"). Although it may seem tempting to
+ * avoid this complication, by simply interpreting a list of folios as a list of
+ * pages, that approach won't work in the longer term, because eventually the
+ * layouts of struct page and struct folio will become completely different.
+ * Furthermore, this pof approach avoids excessive page_folio() calls.
+ */
+struct pages_or_folios {
+	union {
+		struct page **pages;
+		struct folio **folios;
+		void **entries;
+	};
+	bool has_folios;
+	long nr_entries;
+};
+
+static struct folio *pofs_get_folio(struct pages_or_folios *pofs, long i)
+{
+	if (pofs->has_folios)
+		return pofs->folios[i];
+	return page_folio(pofs->pages[i]);
+}
+
+static void pofs_clear_entry(struct pages_or_folios *pofs, long i)
+{
+	pofs->entries[i] = NULL;
+}
+
+static void pofs_unpin(struct pages_or_folios *pofs)
+{
+	if (pofs->has_folios)
+		unpin_folios(pofs->folios, pofs->nr_entries);
+	else
+		unpin_user_pages(pofs->pages, pofs->nr_entries);
+}
+
 /*
  * Returns the number of collected folios. Return value is always >= 0.
  */
 static unsigned long collect_longterm_unpinnable_folios(
-					struct list_head *movable_folio_list,
-					unsigned long nr_folios,
-					struct folio **folios)
+		struct list_head *movable_folio_list,
+		struct pages_or_folios *pofs)
 {
 	unsigned long i, collected = 0;
 	struct folio *prev_folio = NULL;
 	bool drain_allow = true;
 
-	for (i = 0; i < nr_folios; i++) {
-		struct folio *folio = folios[i];
+	for (i = 0; i < pofs->nr_entries; i++) {
+		struct folio *folio = pofs_get_folio(pofs, i);
 
 		if (folio == prev_folio)
 			continue;
@@ -2327,16 +2364,15 @@ static unsigned long collect_longterm_unpinnable_folios(
  * Returns -EAGAIN if all folios were successfully migrated or -errno for
  * failure (or partial success).
  */
-static int migrate_longterm_unpinnable_folios(
-					struct list_head *movable_folio_list,
-					unsigned long nr_folios,
-					struct folio **folios)
+static int
+migrate_longterm_unpinnable_folios(struct list_head *movable_folio_list,
+				   struct pages_or_folios *pofs)
 {
 	int ret;
 	unsigned long i;
 
-	for (i = 0; i < nr_folios; i++) {
-		struct folio *folio = folios[i];
+	for (i = 0; i < pofs->nr_entries; i++) {
+		struct folio *folio = pofs_get_folio(pofs, i);
 
 		if (folio_is_device_coherent(folio)) {
 			/*
@@ -2344,7 +2380,7 @@ static int migrate_longterm_unpinnable_folios(
 			 * convert the pin on the source folio to a normal
 			 * reference.
 			 */
-			folios[i] = NULL;
+			pofs_clear_entry(pofs, i);
 			folio_get(folio);
 			gup_put_folio(folio, 1, FOLL_PIN);
 
@@ -2363,8 +2399,8 @@ static int migrate_longterm_unpinnable_folios(
 		 * calling folio_isolate_lru() which takes a reference so the
 		 * folio won't be freed if it's migrating.
 		 */
-		unpin_folio(folios[i]);
-		folios[i] = NULL;
+		unpin_folio(folio);
+		pofs_clear_entry(pofs, i);
 	}
 
 	if (!list_empty(movable_folio_list)) {
@@ -2387,12 +2423,26 @@ static int migrate_longterm_unpinnable_folios(
 	return -EAGAIN;
 
 err:
-	unpin_folios(folios, nr_folios);
+	pofs_unpin(pofs);
 	putback_movable_pages(movable_folio_list);
 
 	return ret;
 }
 
+static long
+check_and_migrate_movable_pages_or_folios(struct pages_or_folios *pofs)
+{
+	LIST_HEAD(movable_folio_list);
+	unsigned long collected;
+
+	collected = collect_longterm_unpinnable_folios(&movable_folio_list,
+						       pofs);
+	if (!collected)
+		return 0;
+
+	return migrate_longterm_unpinnable_folios(&movable_folio_list, pofs);
+}
+
 /*
  * Check whether all folios are *allowed* to be pinned indefinitely (long term).
  * Rather confusingly, all folios in the range are required to be pinned via
@@ -2417,16 +2467,13 @@ static int migrate_longterm_unpinnable_folios(
 static long check_and_migrate_movable_folios(unsigned long nr_folios,
 					     struct folio **folios)
 {
-	unsigned long collected;
-	LIST_HEAD(movable_folio_list);
+	struct pages_or_folios pofs = {
+		.folios = folios,
+		.has_folios = true,
+		.nr_entries = nr_folios,
+	};
 
-	collected = collect_longterm_unpinnable_folios(&movable_folio_list,
-						       nr_folios, folios);
-	if (!collected)
-		return 0;
-
-	return migrate_longterm_unpinnable_folios(&movable_folio_list,
-						  nr_folios, folios);
+	return check_and_migrate_movable_pages_or_folios(&pofs);
 }
 
 /*
@@ -2436,22 +2483,13 @@ static long check_and_migrate_movable_folios(unsigned long nr_folios,
 static long check_and_migrate_movable_pages(unsigned long nr_pages,
 					    struct page **pages)
 {
-	struct folio **folios;
-	long i, ret;
+	struct pages_or_folios pofs = {
+		.pages = pages,
+		.has_folios = false,
+		.nr_entries = nr_pages,
+	};
 
-	folios = kmalloc_array(nr_pages, sizeof(*folios), GFP_KERNEL);
-	if (!folios) {
-		unpin_user_pages(pages, nr_pages);
-		return -ENOMEM;
-	}
-
-	for (i = 0; i < nr_pages; i++)
-		folios[i] = page_folio(pages[i]);
-
-	ret = check_and_migrate_movable_folios(nr_pages, folios);
-
-	kfree(folios);
-	return ret;
+	return check_and_migrate_movable_pages_or_folios(&pofs);
 }
 #else
 static long check_and_migrate_movable_pages(unsigned long nr_pages,

Re: FAILED: patch "[PATCH] mm/gup: avoid an unnecessary allocation call for" failed to apply to 6.11-stable tree

[John Hubbard]

On 11/17/24 12:33 PM, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 6.11-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
> 
> To reproduce the conflict and resubmit, you may use the following commands:
> 
> git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.11.y
> git checkout FETCH_HEAD
> git cherry-pick -x 94efde1d15399f5c88e576923db9bcd422d217f2
> # <resolve conflicts, build, test, etc.>
> git commit -s
> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024111754-stamina-flyer-1e05@gregkh' --subject-prefix 'PATCH 6.11.y' HEAD^..
> 

It seems that the last hunk didn't apply because it was just too far away,
as far as I can tell. I've manually applied it, resulting in the same diffs
as the original, and did a quick smoke test (boot and ran mm tests).

Here's the updated version for 6.11.y:

From: John Hubbard <jhubbard@nvidia.com>
Date: Sun, 17 Nov 2024 13:08:00 -0800
Subject: [PATCH] mm/gup: avoid an unnecessary allocation call for
  FOLL_LONGTERM cases
X-NVConfidentiality: public
Cc: John Hubbard <jhubbard@nvidia.com>

commit 53ba78de064b ("mm/gup: introduce
check_and_migrate_movable_folios()") created a new constraint on the
pin_user_pages*() API family: a potentially large internal allocation must
now occur, for FOLL_LONGTERM cases.

A user-visible consequence has now appeared: user space can no longer pin
more than 2GB of memory anymore on x86_64.  That's because, on a 4KB
PAGE_SIZE system, when user space tries to (indirectly, via a device
driver that calls pin_user_pages()) pin 2GB, this requires an allocation
of a folio pointers array of MAX_PAGE_ORDER size, which is the limit for
kmalloc().

In addition to the directly visible effect described above, there is also
the problem of adding an unnecessary allocation.  The **pages array
argument has already been allocated, and there is no need for a redundant
**folios array allocation in this case.

Fix this by avoiding the new allocation entirely.  This is done by
referring to either the original page[i] within **pages, or to the
associated folio.  Thanks to David Hildenbrand for suggesting this
approach and for providing the initial implementation (which I've tested
and adjusted slightly) as well.

[jhubbard@nvidia.com]: tweaked the patch to apply to linux-stable/6.11.y
[jhubbard@nvidia.com: whitespace tweak, per David]
   Link: 
https://lkml.kernel.org/r/131cf9c8-ebc0-4cbb-b722-22fa8527bf3c@nvidia.com
[jhubbard@nvidia.com: bypass pofs_get_folio(), per Oscar]
   Link: 
https://lkml.kernel.org/r/c1587c7f-9155-45be-bd62-1e36c0dd6923@nvidia.com
Link: https://lkml.kernel.org/r/20241105032944.141488-2-jhubbard@nvidia.com
Fixes: 53ba78de064b ("mm/gup: introduce check_and_migrate_movable_folios()")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Junxiao Chang <junxiao.chang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
  mm/gup.c | 114 +++++++++++++++++++++++++++++++++++++------------------
  1 file changed, 77 insertions(+), 37 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index 947881ff5e8f..fd3d7900c24b 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2282,20 +2282,57 @@ struct page *get_dump_page(unsigned long addr)
  #endif /* CONFIG_ELF_CORE */

  #ifdef CONFIG_MIGRATION
+
+/*
+ * An array of either pages or folios ("pofs"). Although it may seem 
tempting to
+ * avoid this complication, by simply interpreting a list of folios as 
a list of
+ * pages, that approach won't work in the longer term, because 
eventually the
+ * layouts of struct page and struct folio will become completely 
different.
+ * Furthermore, this pof approach avoids excessive page_folio() calls.
+ */
+struct pages_or_folios {
+	union {
+		struct page **pages;
+		struct folio **folios;
+		void **entries;
+	};
+	bool has_folios;
+	long nr_entries;
+};
+
+static struct folio *pofs_get_folio(struct pages_or_folios *pofs, long i)
+{
+	if (pofs->has_folios)
+		return pofs->folios[i];
+	return page_folio(pofs->pages[i]);
+}
+
+static void pofs_clear_entry(struct pages_or_folios *pofs, long i)
+{
+	pofs->entries[i] = NULL;
+}
+
+static void pofs_unpin(struct pages_or_folios *pofs)
+{
+	if (pofs->has_folios)
+		unpin_folios(pofs->folios, pofs->nr_entries);
+	else
+		unpin_user_pages(pofs->pages, pofs->nr_entries);
+}
+
  /*
   * Returns the number of collected folios. Return value is always >= 0.
   */
  static unsigned long collect_longterm_unpinnable_folios(
-					struct list_head *movable_folio_list,
-					unsigned long nr_folios,
-					struct folio **folios)
+		struct list_head *movable_folio_list,
+		struct pages_or_folios *pofs)
  {
  	unsigned long i, collected = 0;
  	struct folio *prev_folio = NULL;
  	bool drain_allow = true;

-	for (i = 0; i < nr_folios; i++) {
-		struct folio *folio = folios[i];
+	for (i = 0; i < pofs->nr_entries; i++) {
+		struct folio *folio = pofs_get_folio(pofs, i);

  		if (folio == prev_folio)
  			continue;
@@ -2336,16 +2373,15 @@ static unsigned long 
collect_longterm_unpinnable_folios(
   * Returns -EAGAIN if all folios were successfully migrated or -errno for
   * failure (or partial success).
   */
-static int migrate_longterm_unpinnable_folios(
-					struct list_head *movable_folio_list,
-					unsigned long nr_folios,
-					struct folio **folios)
+static int
+migrate_longterm_unpinnable_folios(struct list_head *movable_folio_list,
+				   struct pages_or_folios *pofs)
  {
  	int ret;
  	unsigned long i;

-	for (i = 0; i < nr_folios; i++) {
-		struct folio *folio = folios[i];
+	for (i = 0; i < pofs->nr_entries; i++) {
+		struct folio *folio = pofs_get_folio(pofs, i);

  		if (folio_is_device_coherent(folio)) {
  			/*
@@ -2353,7 +2389,7 @@ static int migrate_longterm_unpinnable_folios(
  			 * convert the pin on the source folio to a normal
  			 * reference.
  			 */
-			folios[i] = NULL;
+			pofs_clear_entry(pofs, i);
  			folio_get(folio);
  			gup_put_folio(folio, 1, FOLL_PIN);

@@ -2372,8 +2408,8 @@ static int migrate_longterm_unpinnable_folios(
  		 * calling folio_isolate_lru() which takes a reference so the
  		 * folio won't be freed if it's migrating.
  		 */
-		unpin_folio(folios[i]);
-		folios[i] = NULL;
+		unpin_folio(folio);
+		pofs_clear_entry(pofs, i);
  	}

  	if (!list_empty(movable_folio_list)) {
@@ -2396,12 +2432,26 @@ static int migrate_longterm_unpinnable_folios(
  	return -EAGAIN;

  err:
-	unpin_folios(folios, nr_folios);
+	pofs_unpin(pofs);
  	putback_movable_pages(movable_folio_list);

  	return ret;
  }

+static long
+check_and_migrate_movable_pages_or_folios(struct pages_or_folios *pofs)
+{
+	LIST_HEAD(movable_folio_list);
+	unsigned long collected;
+
+	collected = collect_longterm_unpinnable_folios(&movable_folio_list,
+						       pofs);
+	if (!collected)
+		return 0;
+
+	return migrate_longterm_unpinnable_folios(&movable_folio_list, pofs);
+}
+
  /*
   * Check whether all folios are *allowed* to be pinned indefinitely 
(longterm).
   * Rather confusingly, all folios in the range are required to be 
pinned via
@@ -2421,16 +2471,13 @@ static int migrate_longterm_unpinnable_folios(
  static long check_and_migrate_movable_folios(unsigned long nr_folios,
  					     struct folio **folios)
  {
-	unsigned long collected;
-	LIST_HEAD(movable_folio_list);
+	struct pages_or_folios pofs = {
+		.folios = folios,
+		.has_folios = true,
+		.nr_entries = nr_folios,
+	};

-	collected = collect_longterm_unpinnable_folios(&movable_folio_list,
-						       nr_folios, folios);
-	if (!collected)
-		return 0;
-
-	return migrate_longterm_unpinnable_folios(&movable_folio_list,
-						  nr_folios, folios);
+	return check_and_migrate_movable_pages_or_folios(&pofs);
  }

  /*
@@ -2442,20 +2489,13 @@ static long 
check_and_migrate_movable_folios(unsigned long nr_folios,
  static long check_and_migrate_movable_pages(unsigned long nr_pages,
  					    struct page **pages)
  {
-	struct folio **folios;
-	long i, ret;
+	struct pages_or_folios pofs = {
+		.pages = pages,
+		.has_folios = false,
+		.nr_entries = nr_pages,
+	};

-	folios = kmalloc_array(nr_pages, sizeof(*folios), GFP_KERNEL);
-	if (!folios)
-		return -ENOMEM;
-
-	for (i = 0; i < nr_pages; i++)
-		folios[i] = page_folio(pages[i]);
-
-	ret = check_and_migrate_movable_folios(nr_pages, folios);
-
-	kfree(folios);
-	return ret;
+	return check_and_migrate_movable_pages_or_folios(&pofs);
  }
  #else
  static long check_and_migrate_movable_pages(unsigned long nr_pages,
-- 
2.47.0

Re: FAILED: patch "[PATCH] mm/gup: avoid an unnecessary allocation call for" failed to apply to 6.11-stable tree

[Greg KH]

On Sun, Nov 17, 2024 at 01:19:09PM -0800, John Hubbard wrote:
> On 11/17/24 12:33 PM, gregkh@linuxfoundation.org wrote:
> > 
> > The patch below does not apply to the 6.11-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> > 
> > To reproduce the conflict and resubmit, you may use the following commands:
> > 
> > git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.11.y
> > git checkout FETCH_HEAD
> > git cherry-pick -x 94efde1d15399f5c88e576923db9bcd422d217f2
> > # <resolve conflicts, build, test, etc.>
> > git commit -s
> > git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024111754-stamina-flyer-1e05@gregkh' --subject-prefix 'PATCH 6.11.y' HEAD^..
> > 
> 
> It seems that the last hunk didn't apply because it was just too far away,
> as far as I can tell. I've manually applied it, resulting in the same diffs
> as the original, and did a quick smoke test (boot and ran mm tests).
> 
> Here's the updated version for 6.11.y:
> 
> From: John Hubbard <jhubbard@nvidia.com>
> Date: Sun, 17 Nov 2024 13:08:00 -0800
> Subject: [PATCH] mm/gup: avoid an unnecessary allocation call for
>  FOLL_LONGTERM cases
> X-NVConfidentiality: public
> Cc: John Hubbard <jhubbard@nvidia.com>
> 
> commit 53ba78de064b ("mm/gup: introduce
> check_and_migrate_movable_folios()") created a new constraint on the
> pin_user_pages*() API family: a potentially large internal allocation must
> now occur, for FOLL_LONGTERM cases.
> 
> A user-visible consequence has now appeared: user space can no longer pin
> more than 2GB of memory anymore on x86_64.  That's because, on a 4KB
> PAGE_SIZE system, when user space tries to (indirectly, via a device
> driver that calls pin_user_pages()) pin 2GB, this requires an allocation
> of a folio pointers array of MAX_PAGE_ORDER size, which is the limit for
> kmalloc().
> 
> In addition to the directly visible effect described above, there is also
> the problem of adding an unnecessary allocation.  The **pages array
> argument has already been allocated, and there is no need for a redundant
> **folios array allocation in this case.
> 
> Fix this by avoiding the new allocation entirely.  This is done by
> referring to either the original page[i] within **pages, or to the
> associated folio.  Thanks to David Hildenbrand for suggesting this
> approach and for providing the initial implementation (which I've tested
> and adjusted slightly) as well.
> 
> [jhubbard@nvidia.com]: tweaked the patch to apply to linux-stable/6.11.y
> [jhubbard@nvidia.com: whitespace tweak, per David]
>   Link:
> https://lkml.kernel.org/r/131cf9c8-ebc0-4cbb-b722-22fa8527bf3c@nvidia.com
> [jhubbard@nvidia.com: bypass pofs_get_folio(), per Oscar]
>   Link:
> https://lkml.kernel.org/r/c1587c7f-9155-45be-bd62-1e36c0dd6923@nvidia.com
> Link: https://lkml.kernel.org/r/20241105032944.141488-2-jhubbard@nvidia.com
> Fixes: 53ba78de064b ("mm/gup: introduce check_and_migrate_movable_folios()")
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Acked-by: David Hildenbrand <david@redhat.com>
> Reviewed-by: Oscar Salvador <osalvador@suse.de>
> Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Christoph Hellwig <hch@infradead.org>
> Cc: Jason Gunthorpe <jgg@nvidia.com>
> Cc: Peter Xu <peterx@redhat.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Dongwon Kim <dongwon.kim@intel.com>
> Cc: Hugh Dickins <hughd@google.com>
> Cc: Junxiao Chang <junxiao.chang@intel.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>  mm/gup.c | 114 +++++++++++++++++++++++++++++++++++++------------------
>  1 file changed, 77 insertions(+), 37 deletions(-)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index 947881ff5e8f..fd3d7900c24b 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -2282,20 +2282,57 @@ struct page *get_dump_page(unsigned long addr)
>  #endif /* CONFIG_ELF_CORE */
> 
>  #ifdef CONFIG_MIGRATION
> +
> +/*
> + * An array of either pages or folios ("pofs"). Although it may seem
> tempting to
> + * avoid this complication, by simply interpreting a list of folios as a
> list of
> + * pages, that approach won't work in the longer term, because eventually
> the
> + * layouts of struct page and struct folio will become completely
> different.
> + * Furthermore, this pof approach avoids excessive page_folio() calls.

Patch is line-wrapped :(

Can you resend it in a format I can apply it in?

thanks,

greg k-h

Re: FAILED: patch "[PATCH] mm/gup: avoid an unnecessary allocation call for" failed to apply to 6.11-stable tree

[John Hubbard]

On 11/17/24 1:25 PM, Greg KH wrote:
> On Sun, Nov 17, 2024 at 01:19:09PM -0800, John Hubbard wrote:
>> On 11/17/24 12:33 PM, gregkh@linuxfoundation.org wrote:
...
> Patch is line-wrapped :(
> 
> Can you resend it in a format I can apply it in?
> 
> thanks,
> 
> greg k-h

OK, I'm going to use git-send-email after all. Thunderbird is clearly
not The Way here.  Just a sec. :)


thanks,
-- 
John Hubbard

Re: FAILED: patch "[PATCH] mm/gup: avoid an unnecessary allocation call for" failed to apply to 6.11-stable tree

[John Hubbard]

On 11/17/24 1:27 PM, John Hubbard wrote:
> On 11/17/24 1:25 PM, Greg KH wrote:
>> On Sun, Nov 17, 2024 at 01:19:09PM -0800, John Hubbard wrote:
>>> On 11/17/24 12:33 PM, gregkh@linuxfoundation.org wrote:
> ...
>> Patch is line-wrapped :(
>>
>> Can you resend it in a format I can apply it in?
>>
>> thanks,
>>
>> greg k-h
> 
> OK, I'm going to use git-send-email after all. Thunderbird is clearly
> not The Way here.  Just a sec. :)
> 

OK, I've sent the fixed up version, here:

https://lore.kernel.org/20241117213229.104346-1-jhubbard@nvidia.com


thanks,
-- 
John Hubbard

Re: FAILED: patch "[PATCH] mm/gup: avoid an unnecessary allocation call for" failed to apply to 6.11-stable tree

[Greg KH]

On Sun, Nov 17, 2024 at 01:38:42PM -0800, John Hubbard wrote:
> On 11/17/24 1:27 PM, John Hubbard wrote:
> > On 11/17/24 1:25 PM, Greg KH wrote:
> > > On Sun, Nov 17, 2024 at 01:19:09PM -0800, John Hubbard wrote:
> > > > On 11/17/24 12:33 PM, gregkh@linuxfoundation.org wrote:
> > ...
> > > Patch is line-wrapped :(
> > > 
> > > Can you resend it in a format I can apply it in?
> > > 
> > > thanks,
> > > 
> > > greg k-h
> > 
> > OK, I'm going to use git-send-email after all. Thunderbird is clearly
> > not The Way here.  Just a sec. :)
> > 
> 
> OK, I've sent the fixed up version, here:
> 
> https://lore.kernel.org/20241117213229.104346-1-jhubbard@nvidia.com

That worked, thanks!