diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2009-12-17 15:27:15 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-17 15:45:31 -0800 |
| commit | 9cd80bbb07fcd6d4d037fad4297496d3b132ac6b (patch) | |
| tree | 322216d34b6d5ba2366f53ba0d677950c4cde766 /fs/exec.c | |
| parent | 0f67b0b0392ccca98459bf40b36c0037793b5f71 (diff) | |
| download | linux-3.10-9cd80bbb07fcd6d4d037fad4297496d3b132ac6b.tar.gz linux-3.10-9cd80bbb07fcd6d4d037fad4297496d3b132ac6b.tar.bz2 linux-3.10-9cd80bbb07fcd6d4d037fad4297496d3b132ac6b.zip | |
do_wait() optimization: do not place sub-threads on task_struct->children list
Thanks to Roland who pointed out de_thread() issues.
Currently we add sub-threads to ->real_parent->children list. This buys
nothing but slows down do_wait().
With this patch ->children contains only main threads (group leaders).
The only complication is that forget_original_parent() should iterate over
sub-threads by hand, and de_thread() needs another list_replace() when it
changes ->group_leader.
Henceforth do_wait_thread() can never see task_detached() && !EXIT_DEAD
tasks, we can remove this check (and we can unify do_wait_thread() and
ptrace_do_wait()).
This change can confuse the optimistic search in mm_update_next_owner(),
but this is fixable and minor.
Perhaps badness() and oom_kill_process() should be updated, but they
should be fixed in any case.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ratan Nalumasu <rnalumasu@gmail.com>
Cc: Vitaly Mayatskikh <vmayatsk@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/exec.c')
| -rw-r--r-- | fs/exec.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/exec.c b/fs/exec.c index 623a5cc3076..77db9a97a77 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -826,7 +826,9 @@ static int de_thread(struct task_struct *tsk) attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); transfer_pid(leader, tsk, PIDTYPE_PGID); transfer_pid(leader, tsk, PIDTYPE_SID); + list_replace_rcu(&leader->tasks, &tsk->tasks); + list_replace_init(&leader->sibling, &tsk->sibling); tsk->group_leader = tsk; leader->group_leader = tsk; |