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authorOleg Nesterov <oleg@redhat.com>2009-01-06 14:40:29 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-06 15:59:09 -0800
commit901608d9045146aec6f14a7777ea4b1501c379f0 (patch)
tree0155189f48479b920855dedccba6829363376d4d /kernel/tsacct.c
parent67d58ac47d25f7e2a105248a4aea6113131ab874 (diff)
downloadlinux-sh-901608d9045146aec6f14a7777ea4b1501c379f0.tar.gz
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/tsacct.c')
-rw-r--r--kernel/tsacct.c4
1 files changed, 2 insertions, 2 deletions
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;