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authorOleg Nesterov <oleg@redhat.com>2009-09-22 16:45:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-23 07:39:40 -0700
commit9b4d1cbef8f41aff2b3e4ca31f566c071fe601de (patch)
treefc64d537b5142646d917ad928e3fb1df4caf4655 /fs
parentcff4edb591c153a779a27a3fd8e7bc1217f2f6b8 (diff)
downloadlinux-9b4d1cbef8f41aff2b3e4ca31f566c071fe601de.tar.gz
proc_flush_task: flush /proc/tid/task/pid when a sub-thread exits
The exiting sub-thread flushes /proc/pid only, but this doesn't buy too much: ps and friends mostly use /proc/tid/task/pid. Remove "if (thread_group_leader())" checks from proc_flush_task() path, this means we always remove /proc/tid/task/pid dentry on exit, and this actually matches the comment above proc_flush_task(). The test-case: static void* tfunc(void *arg) { char name[256]; sprintf(name, "/proc/%d/task/%ld/status", getpid(), gettid()); close(open(name, O_RDONLY)); return NULL; } int main(void) { pthread_t t; for (;;) { if (!pthread_create(&t, NULL, &tfunc, NULL)) pthread_join(t, NULL); } } slabtop shows that pid/proc_inode_cache/etc grow quickly and "indefinitely" until the task is killed or shrink_slab() is called, not good. And the main thread needs a lot of time to exit. The same can happen if something like "ps -efL" runs continuously, while some application spawns short-living threads. Reported-by: "James M. Leddy" <jleddy@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dominic Duval <dduval@redhat.com> Cc: Frank Hirtz <fhirtz@redhat.com> Cc: "Fuller, Johnray" <Johnray.Fuller@gs.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Paul Batkowski <pbatkowski@redhat.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/base.c10
1 files changed, 3 insertions, 7 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 69bb70351b9b..5bc587049b37 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2604,9 +2604,6 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
dput(dentry);
}
- if (tgid == 0)
- goto out;
-
name.name = buf;
name.len = snprintf(buf, sizeof(buf), "%d", tgid);
leader = d_hash_and_lookup(mnt->mnt_root, &name);
@@ -2663,17 +2660,16 @@ out:
void proc_flush_task(struct task_struct *task)
{
int i;
- struct pid *pid, *tgid = NULL;
+ struct pid *pid, *tgid;
struct upid *upid;
pid = task_pid(task);
- if (thread_group_leader(task))
- tgid = task_tgid(task);
+ tgid = task_tgid(task);
for (i = 0; i <= pid->level; i++) {
upid = &pid->numbers[i];
proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
- tgid ? tgid->numbers[i].nr : 0);
+ tgid->numbers[i].nr);
}
upid = &pid->numbers[pid->level];