The patch titled
Subject: proc: add a reschedule point in proc_readfd_common()
has been added to the -mm tree. Its filename is
proc-add-a-reschedule-point-in-proc_readfd_common.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/proc-add-a-reschedule-point-in-proc_readfd_common.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/proc-add-a-reschedule-point-in-proc_readfd_common.patch
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------------------------------------------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
Subject: proc: add a reschedule point in proc_readfd_common()
User can pass an arbitrary large buffer to getdents().
It is typically a 32KB buffer used by libc scandir() implementation.
When scanning /proc/{pid}/fd, we can hold cpu way too long, so add a
cond_resched() to be kind with other tasks.
We've seen latencies of more than 50ms on real workloads.
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/fd.c | 1 +
1 file changed, 1 insertion(+)
diff -puN fs/proc/fd.c~proc-add-a-reschedule-point-in-proc_readfd_common fs/proc/fd.c
--- a/fs/proc/fd.c~proc-add-a-reschedule-point-in-proc_readfd_common
+++ a/fs/proc/fd.c
@@ -258,6 +258,7 @@ static int proc_readfd_common(struct fil
name, len, instantiate, p,
(void *)(unsigned long)fd))
goto out_fd_loop;
+ cond_resched();
rcu_read_lock();
}
rcu_read_unlock();
_
Patches currently in -mm which might be from edumazet@xxxxxxxxxx are
proc-add-a-reschedule-point-in-proc_readfd_common.patch
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