The patch titled
Subject: mm, memcg: use consistent gfp flags during readahead
has been added to the -mm tree. Its filename is
mm-memcg-use-consistent-gfp-flags-during-readahead.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-use-consistent-gfp-flags-during-readahead.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-use-consistent-gfp-flags-during-readahead.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Michal Hocko <mhocko@xxxxxxxx>
Subject: mm, memcg: use consistent gfp flags during readahead
Vladimir has noticed that we might declare memcg oom even during readahead
because read_pages only uses GFP_KERNEL (with mapping_gfp restriction)
while __do_page_cache_readahead uses page_cache_alloc_readahead which adds
__GFP_NORETRY to prevent from OOMs. This gfp mask discrepancy is really
unfortunate and easily fixable. Drop page_cache_alloc_readahead() which
only has one user and outsource the gfp_mask logic into readahead_gfp_mask
and propagate this mask from __do_page_cache_readahead down to read_pages.
This alone would have only very limited impact as most filesystems are
implementing ->readpages and the common implementation mpage_readpages
does GFP_KERNEL (with mapping_gfp restriction) again. We can tell it to
use readahead_gfp_mask instead as this function is called only during
readahead as well. The same applies to read_cache_pages.
ext4 has its own ext4_mpage_readpages but the path which has pages != NULL
can use the same gfp mask. Btrfs, cifs, f2fs and orangefs are doing a
very similar pattern to mpage_readpages so the same can be applied to them
as well.
Link: http://lkml.kernel.org/r/1465301556-26431-1-git-send-email-mhocko@xxxxxxxxxx
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: Chris Mason <clm@xxxxxx>
Cc: Steve French <sfrench@xxxxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Mike Marshall <hubcap@xxxxxxxxxxxx>
Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Cc: Changman Lee <cm224.lee@xxxxxxxxxxx>
Cc: Chao Yu <yuchao0@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/extent_io.c | 3 ++-
fs/cifs/file.c | 2 +-
fs/ext4/readpage.c | 2 +-
fs/f2fs/data.c | 3 ++-
fs/mpage.c | 2 +-
fs/orangefs/inode.c | 2 +-
include/linux/pagemap.h | 6 +++---
mm/readahead.c | 12 ++++++------
8 files changed, 17 insertions(+), 15 deletions(-)
diff -puN fs/btrfs/extent_io.c~mm-memcg-use-consistent-gfp-flags-during-readahead fs/btrfs/extent_io.c
--- a/fs/btrfs/extent_io.c~mm-memcg-use-consistent-gfp-flags-during-readahead
+++ a/fs/btrfs/extent_io.c
@@ -4180,7 +4180,8 @@ int extent_readpages(struct extent_io_tr
prefetchw(&page->flags);
list_del(&page->lru);
if (add_to_page_cache_lru(page, mapping,
- page->index, GFP_NOFS)) {
+ page->index,
+ readahead_gfp_mask(mapping))) {
put_page(page);
continue;
}
diff -puN fs/cifs/file.c~mm-memcg-use-consistent-gfp-flags-during-readahead fs/cifs/file.c
--- a/fs/cifs/file.c~mm-memcg-use-consistent-gfp-flags-during-readahead
+++ a/fs/cifs/file.c
@@ -3358,7 +3358,7 @@ readpages_get_pages(struct address_space
struct page *page, *tpage;
unsigned int expected_index;
int rc;
- gfp_t gfp = mapping_gfp_constraint(mapping, GFP_KERNEL);
+ gfp_t gfp = readahead_gfp_mask(mapping);
INIT_LIST_HEAD(tmplist);
diff -puN fs/ext4/readpage.c~mm-memcg-use-consistent-gfp-flags-during-readahead fs/ext4/readpage.c
--- a/fs/ext4/readpage.c~mm-memcg-use-consistent-gfp-flags-during-readahead
+++ a/fs/ext4/readpage.c
@@ -166,7 +166,7 @@ int ext4_mpage_readpages(struct address_
page = list_entry(pages->prev, struct page, lru);
list_del(&page->lru);
if (add_to_page_cache_lru(page, mapping, page->index,
- mapping_gfp_constraint(mapping, GFP_KERNEL)))
+ readahead_gfp_mask(mapping)))
goto next_page;
}
diff -puN fs/f2fs/data.c~mm-memcg-use-consistent-gfp-flags-during-readahead fs/f2fs/data.c
--- a/fs/f2fs/data.c~mm-memcg-use-consistent-gfp-flags-during-readahead
+++ a/fs/f2fs/data.c
@@ -996,7 +996,8 @@ static int f2fs_mpage_readpages(struct a
page = list_entry(pages->prev, struct page, lru);
list_del(&page->lru);
if (add_to_page_cache_lru(page, mapping,
- page->index, GFP_KERNEL))
+ page->index,
+ readahead_gfp_mask(mapping)))
goto next_page;
}
diff -puN fs/mpage.c~mm-memcg-use-consistent-gfp-flags-during-readahead fs/mpage.c
--- a/fs/mpage.c~mm-memcg-use-consistent-gfp-flags-during-readahead
+++ a/fs/mpage.c
@@ -362,7 +362,7 @@ mpage_readpages(struct address_space *ma
sector_t last_block_in_bio = 0;
struct buffer_head map_bh;
unsigned long first_logical_block = 0;
- gfp_t gfp = mapping_gfp_constraint(mapping, GFP_KERNEL);
+ gfp_t gfp = readahead_gfp_mask(mapping);
map_bh.b_state = 0;
map_bh.b_size = 0;
diff -puN fs/orangefs/inode.c~mm-memcg-use-consistent-gfp-flags-during-readahead fs/orangefs/inode.c
--- a/fs/orangefs/inode.c~mm-memcg-use-consistent-gfp-flags-during-readahead
+++ a/fs/orangefs/inode.c
@@ -80,7 +80,7 @@ static int orangefs_readpages(struct fil
if (!add_to_page_cache(page,
mapping,
page->index,
- GFP_KERNEL)) {
+ readahead_gfp_mask(mapping))) {
ret = read_one_page(page);
gossip_debug(GOSSIP_INODE_DEBUG,
"failure adding page to cache, read_one_page returned: %d\n",
diff -puN include/linux/pagemap.h~mm-memcg-use-consistent-gfp-flags-during-readahead include/linux/pagemap.h
--- a/include/linux/pagemap.h~mm-memcg-use-consistent-gfp-flags-during-readahead
+++ a/include/linux/pagemap.h
@@ -209,10 +209,10 @@ static inline struct page *page_cache_al
return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_COLD);
}
-static inline struct page *page_cache_alloc_readahead(struct address_space *x)
+static inline gfp_t readahead_gfp_mask(struct address_space *x)
{
- return __page_cache_alloc(mapping_gfp_mask(x) |
- __GFP_COLD | __GFP_NORETRY | __GFP_NOWARN);
+ return mapping_gfp_mask(x) |
+ __GFP_COLD | __GFP_NORETRY | __GFP_NOWARN;
}
typedef int filler_t(void *, struct page *);
diff -puN mm/readahead.c~mm-memcg-use-consistent-gfp-flags-during-readahead mm/readahead.c
--- a/mm/readahead.c~mm-memcg-use-consistent-gfp-flags-during-readahead
+++ a/mm/readahead.c
@@ -89,7 +89,7 @@ int read_cache_pages(struct address_spac
page = lru_to_page(pages);
list_del(&page->lru);
if (add_to_page_cache_lru(page, mapping, page->index,
- mapping_gfp_constraint(mapping, GFP_KERNEL))) {
+ readahead_gfp_mask(mapping))) {
read_cache_pages_invalidate_page(mapping, page);
continue;
}
@@ -108,7 +108,7 @@ int read_cache_pages(struct address_spac
EXPORT_SYMBOL(read_cache_pages);
static int read_pages(struct address_space *mapping, struct file *filp,
- struct list_head *pages, unsigned nr_pages)
+ struct list_head *pages, unsigned nr_pages, gfp_t gfp_mask)
{
struct blk_plug plug;
unsigned page_idx;
@@ -126,8 +126,7 @@ static int read_pages(struct address_spa
for (page_idx = 0; page_idx < nr_pages; page_idx++) {
struct page *page = lru_to_page(pages);
list_del(&page->lru);
- if (!add_to_page_cache_lru(page, mapping, page->index,
- mapping_gfp_constraint(mapping, GFP_KERNEL))) {
+ if (!add_to_page_cache_lru(page, mapping, page->index, gfp_mask)) {
mapping->a_ops->readpage(filp, page);
}
put_page(page);
@@ -159,6 +158,7 @@ int __do_page_cache_readahead(struct add
int page_idx;
int ret = 0;
loff_t isize = i_size_read(inode);
+ gfp_t gfp_mask = readahead_gfp_mask(mapping);
if (isize == 0)
goto out;
@@ -180,7 +180,7 @@ int __do_page_cache_readahead(struct add
if (page && !radix_tree_exceptional_entry(page))
continue;
- page = page_cache_alloc_readahead(mapping);
+ page = __page_cache_alloc(gfp_mask);
if (!page)
break;
page->index = page_offset;
@@ -196,7 +196,7 @@ int __do_page_cache_readahead(struct add
* will then handle the error.
*/
if (ret)
- read_pages(mapping, filp, &page_pool, ret);
+ read_pages(mapping, filp, &page_pool, ret, gfp_mask);
BUG_ON(!list_empty(&page_pool));
out:
return ret;
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
tree-wide-get-rid-of-__gfp_repeat-for-order-0-allocations-part-i.patch
x86-get-rid-of-superfluous-__gfp_repeat.patch
x86-efi-get-rid-of-superfluous-__gfp_repeat.patch
arm-get-rid-of-superfluous-__gfp_repeat.patch
arm64-get-rid-of-superfluous-__gfp_repeat.patch
arc-get-rid-of-superfluous-__gfp_repeat.patch
mips-get-rid-of-superfluous-__gfp_repeat.patch
nios2-get-rid-of-superfluous-__gfp_repeat.patch
parisc-get-rid-of-superfluous-__gfp_repeat.patch
score-get-rid-of-superfluous-__gfp_repeat.patch
powerpc-get-rid-of-superfluous-__gfp_repeat.patch
sparc-get-rid-of-superfluous-__gfp_repeat.patch
s390-get-rid-of-superfluous-__gfp_repeat.patch
sh-get-rid-of-superfluous-__gfp_repeat.patch
tile-get-rid-of-superfluous-__gfp_repeat.patch
unicore32-get-rid-of-superfluous-__gfp_repeat.patch
jbd2-get-rid-of-superfluous-__gfp_repeat.patch
mm-oom_reaper-make-sure-that-mmput_async-is-called-only-when-memory-was-reaped.patch
mm-memcg-use-consistent-gfp-flags-during-readahead.patch
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