From: Michal Hocko <[email protected]> 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.
Cc: Benamin LaHaise <[email protected]> Cc: Alexander Viro <[email protected]> Acked-by: Jeff Moyer <[email protected]> Acked-by: Vlastimil Babka <[email protected]> Signed-off-by: Michal Hocko <[email protected]> --- fs/aio.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/aio.c b/fs/aio.c index 155f84253f33..be771046d77c 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -496,7 +496,12 @@ static int aio_setup_ring(struct kioctx *ctx) 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); -- 2.8.0.rc3
