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author | Oleg Nesterov <oleg@redhat.com> | 2009-01-06 14:40:29 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-06 15:59:09 -0800 |
commit | 901608d9045146aec6f14a7777ea4b1501c379f0 (patch) | |
tree | 0155189f48479b920855dedccba6829363376d4d /kernel | |
parent | 67d58ac47d25f7e2a105248a4aea6113131ab874 (diff) | |
download | linux-901608d9045146aec6f14a7777ea4b1501c379f0.tar.bz2 |
mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting
xacct_add_tsk() relies on do_exit()->update_hiwater_xxx() and uses
mm->hiwater_xxx directly, this leads to 2 problems:
- taskstats_user_cmd() can call fill_pid()->xacct_add_tsk() at any
moment before the task exits, so we should check the current values of
rss/vm anyway.
- do_exit()->update_hiwater_xxx() calls are racy. An exiting thread can
be preempted right before mm->hiwater_xxx = new_val, and another thread
can use A_LOT of memory and exit in between. When the first thread
resumes it can be the last thread in the thread group, in that case we
report the wrong hiwater_xxx values which do not take A_LOT into
account.
Introduce get_mm_hiwater_rss() and get_mm_hiwater_vm() helpers and change
xacct_add_tsk() to use them. The first helper will also be used by
rusage->ru_maxrss accounting.
Kill do_exit()->update_hiwater_xxx() calls. Unless we are going to
decrease rss/vm there is no point to update mm->hiwater_xxx, and nobody
can look at this mm_struct when exit_mmap() actually unmaps the memory.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/exit.c | 5 | ||||
-rw-r--r-- | kernel/tsacct.c | 4 |
2 files changed, 3 insertions, 6 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index f923724ab3c9..c7740fa3252c 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1051,10 +1051,7 @@ NORET_TYPE void do_exit(long code) preempt_count()); acct_update_integrals(tsk); - if (tsk->mm) { - update_hiwater_rss(tsk->mm); - update_hiwater_vm(tsk->mm); - } + group_dead = atomic_dec_and_test(&tsk->signal->live); if (group_dead) { hrtimer_cancel(&tsk->signal->real_timer); diff --git a/kernel/tsacct.c b/kernel/tsacct.c index 2dc06ab35716..43f891b05a4b 100644 --- a/kernel/tsacct.c +++ b/kernel/tsacct.c @@ -92,8 +92,8 @@ void xacct_add_tsk(struct taskstats *stats, struct task_struct *p) mm = get_task_mm(p); if (mm) { /* adjust to KB unit */ - stats->hiwater_rss = mm->hiwater_rss * PAGE_SIZE / KB; - stats->hiwater_vm = mm->hiwater_vm * PAGE_SIZE / KB; + stats->hiwater_rss = get_mm_hiwater_rss(mm) * PAGE_SIZE / KB; + stats->hiwater_vm = get_mm_hiwater_vm(mm) * PAGE_SIZE / KB; mmput(mm); } stats->read_char = p->ioac.rchar; |