summaryrefslogtreecommitdiff
path: root/mm/filemap.c
diff options
context:
space:
mode:
authorJens Axboe <axboe@kernel.dk>2022-07-01 14:04:43 -0600
committerJens Axboe <axboe@kernel.dk>2022-07-24 18:39:32 -0600
commit0dd316ba8692c2374fbb82cce57c0b23144f2977 (patch)
tree8daef3b112bfa06b7c1b95b6409060f03f7d5137 /mm/filemap.c
parent1aa91d9c993397858a50c433933ea119903fdea2 (diff)
If we're creating a page cache page with FGP_CREAT but FGP_NOWAIT is set, we should dial back the gfp flags to avoid frivolous blocking which is trivial to hit in low memory conditions: [ 10.117661] __schedule+0x8c/0x550 [ 10.118305] schedule+0x58/0xa0 [ 10.118897] schedule_timeout+0x30/0xdc [ 10.119610] __wait_for_common+0x88/0x114 [ 10.120348] wait_for_completion+0x1c/0x24 [ 10.121103] __flush_work.isra.0+0x16c/0x19c [ 10.121896] flush_work+0xc/0x14 [ 10.122496] __drain_all_pages+0x144/0x218 [ 10.123267] drain_all_pages+0x10/0x18 [ 10.123941] __alloc_pages+0x464/0x9e4 [ 10.124633] __folio_alloc+0x18/0x3c [ 10.125294] __filemap_get_folio+0x17c/0x204 [ 10.126084] iomap_write_begin+0xf8/0x428 [ 10.126829] iomap_file_buffered_write+0x144/0x24c [ 10.127710] xfs_file_buffered_write+0xe8/0x248 [ 10.128553] xfs_file_write_iter+0xa8/0x120 [ 10.129324] io_write+0x16c/0x38c [ 10.129940] io_issue_sqe+0x70/0x1cc [ 10.130617] io_queue_sqe+0x18/0xfc [ 10.131277] io_submit_sqes+0x5d4/0x600 [ 10.131946] __arm64_sys_io_uring_enter+0x224/0x600 [ 10.132752] invoke_syscall.constprop.0+0x70/0xc0 [ 10.133616] do_el0_svc+0xd0/0x118 [ 10.134238] el0_svc+0x78/0xa0 Clear IO, FS, and reclaim flags and mark the allocation as GFP_NOWAIT and add __GFP_NOWARN to avoid polluting dmesg with pointless allocations failures. A caller with FGP_NOWAIT must be expected to handle the resulting -EAGAIN return and retry from a suitable context without NOWAIT set. Reviewed-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index ffdfbc8b0e3c..254931a6e3ed 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1988,6 +1988,10 @@ no_page:
gfp |= __GFP_WRITE;
if (fgp_flags & FGP_NOFS)
gfp &= ~__GFP_FS;
+ if (fgp_flags & FGP_NOWAIT) {
+ gfp &= ~GFP_KERNEL;
+ gfp |= GFP_NOWAIT | __GFP_NOWARN;
+ }
folio = filemap_alloc_folio(gfp, 0);
if (!folio)