From: Michal Hocko <mhocko@xxxxxxxx>
Subject: aio: make aio_setup_ring killable
aio_setup_ring waits for mmap_sem in writable mode. If the waiting task
gets killed by the oom killer it would block oom_reaper from asynchronous
address space reclaim and reduce the chances of timely OOM resolving.
Wait for the lock in the killable mode and return with EINTR if the task
got killed while waiting. This will also expedite the return to the
userspace and do_exit.
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Benamin LaHaise <bcrl@xxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/aio.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff -puN fs/aio.c~aio-make-aio_setup_ring-killable fs/aio.c
--- a/fs/aio.c~aio-make-aio_setup_ring-killable
+++ a/fs/aio.c
@@ -496,7 +496,12 @@ static int aio_setup_ring(struct kioctx
ctx->mmap_size = nr_pages * PAGE_SIZE;
pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
- down_write(&mm->mmap_sem);
+ if (down_write_killable(&mm->mmap_sem)) {
+ ctx->mmap_size = 0;
+ aio_free_ring(ctx);
+ return -EINTR;
+ }
+
ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size,
PROT_READ | PROT_WRITE,
MAP_SHARED, 0, &unused);
_
--
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