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authorNeilBrown <neilb@suse.de>2022-01-15 01:07:14 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-01-15 17:30:29 +0300
commit4034247a0d6ab281ba3293798ce67af494d86129 (patch)
tree888a53c1c79490500c719b46894267e4f445264a /fs/ext4
parent704687deaae768a818d7da0584ee021793a97684 (diff)
downloadlinux-4034247a0d6ab281ba3293798ce67af494d86129.tar.xz
mm: introduce memalloc_retry_wait()
Various places in the kernel - largely in filesystems - respond to a memory allocation failure by looping around and re-trying. Some of these cannot conveniently use __GFP_NOFAIL, for reasons such as: - a GFP_ATOMIC allocation, which __GFP_NOFAIL doesn't work on - a need to check for the process being signalled between failures - the possibility that other recovery actions could be performed - the allocation is quite deep in support code, and passing down an extra flag to say if __GFP_NOFAIL is wanted would be clumsy. Many of these currently use congestion_wait() which (in almost all cases) simply waits the given timeout - congestion isn't tracked for most devices. It isn't clear what the best delay is for loops, but it is clear that the various filesystems shouldn't be responsible for choosing a timeout. This patch introduces memalloc_retry_wait() with takes on that responsibility. Code that wants to retry a memory allocation can call this function passing the GFP flags that were used. It will wait however is appropriate. For now, it only considers __GFP_NORETRY and whatever gfpflags_allow_blocking() tests. If blocking is allowed without __GFP_NORETRY, then alloc_page either made some reclaim progress, or waited for a while, before failing. So there is no need for much further waiting. memalloc_retry_wait() will wait until the current jiffie ends. If this condition is not met, then alloc_page() won't have waited much if at all. In that case memalloc_retry_wait() waits about 200ms. This is the delay that most current loops uses. linux/sched/mm.h needs to be included in some files now, but linux/backing-dev.h does not. Link: https://lkml.kernel.org/r/163754371968.13692.1277530886009912421@noble.neil.brown.name Signed-off-by: NeilBrown <neilb@suse.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Chao Yu <chao@kernel.org> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/extents.c8
-rw-r--r--fs/ext4/inline.c5
-rw-r--r--fs/ext4/page-io.c9
3 files changed, 10 insertions, 12 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 0ecf819bf189..5582fba36b44 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -27,8 +27,8 @@
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/fiemap.h>
-#include <linux/backing-dev.h>
#include <linux/iomap.h>
+#include <linux/sched/mm.h>
#include "ext4_jbd2.h"
#include "ext4_extents.h"
#include "xattr.h"
@@ -4407,8 +4407,7 @@ retry:
err = ext4_es_remove_extent(inode, last_block,
EXT_MAX_BLOCKS - last_block);
if (err == -ENOMEM) {
- cond_resched();
- congestion_wait(BLK_RW_ASYNC, HZ/50);
+ memalloc_retry_wait(GFP_ATOMIC);
goto retry;
}
if (err)
@@ -4416,8 +4415,7 @@ retry:
retry_remove_space:
err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
if (err == -ENOMEM) {
- cond_resched();
- congestion_wait(BLK_RW_ASYNC, HZ/50);
+ memalloc_retry_wait(GFP_ATOMIC);
goto retry_remove_space;
}
return err;
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 39a1ab129fdc..635bcf68a67e 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -7,7 +7,7 @@
#include <linux/iomap.h>
#include <linux/fiemap.h>
#include <linux/iversion.h>
-#include <linux/backing-dev.h>
+#include <linux/sched/mm.h>
#include "ext4_jbd2.h"
#include "ext4.h"
@@ -1929,8 +1929,7 @@ int ext4_inline_data_truncate(struct inode *inode, int *has_inline)
retry:
err = ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
if (err == -ENOMEM) {
- cond_resched();
- congestion_wait(BLK_RW_ASYNC, HZ/50);
+ memalloc_retry_wait(GFP_ATOMIC);
goto retry;
}
if (err)
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 9cb261714991..1d370364230e 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -24,7 +24,7 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
-#include <linux/backing-dev.h>
+#include <linux/sched/mm.h>
#include "ext4_jbd2.h"
#include "xattr.h"
@@ -523,12 +523,13 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
ret = PTR_ERR(bounce_page);
if (ret == -ENOMEM &&
(io->io_bio || wbc->sync_mode == WB_SYNC_ALL)) {
- gfp_flags = GFP_NOFS;
+ gfp_t new_gfp_flags = GFP_NOFS;
if (io->io_bio)
ext4_io_submit(io);
else
- gfp_flags |= __GFP_NOFAIL;
- congestion_wait(BLK_RW_ASYNC, HZ/50);
+ new_gfp_flags |= __GFP_NOFAIL;
+ memalloc_retry_wait(gfp_flags);
+ gfp_flags = new_gfp_flags;
goto retry_encrypt;
}