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authorOleg Nesterov <oleg@redhat.com>2009-01-06 17:40:29 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-06 18:59:09 -0500
commit901608d9045146aec6f14a7777ea4b1501c379f0 (patch)
tree0155189f48479b920855dedccba6829363376d4d /kernel
parent67d58ac47d25f7e2a105248a4aea6113131ab874 (diff)
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.c5
-rw-r--r--kernel/tsacct.c4
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)
1051 preempt_count()); 1051 preempt_count());
1052 1052
1053 acct_update_integrals(tsk); 1053 acct_update_integrals(tsk);
1054 if (tsk->mm) { 1054
1055 update_hiwater_rss(tsk->mm);
1056 update_hiwater_vm(tsk->mm);
1057 }
1058 group_dead = atomic_dec_and_test(&tsk->signal->live); 1055 group_dead = atomic_dec_and_test(&tsk->signal->live);
1059 if (group_dead) { 1056 if (group_dead) {
1060 hrtimer_cancel(&tsk->signal->real_timer); 1057 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)
92 mm = get_task_mm(p); 92 mm = get_task_mm(p);
93 if (mm) { 93 if (mm) {
94 /* adjust to KB unit */ 94 /* adjust to KB unit */
95 stats->hiwater_rss = mm->hiwater_rss * PAGE_SIZE / KB; 95 stats->hiwater_rss = get_mm_hiwater_rss(mm) * PAGE_SIZE / KB;
96 stats->hiwater_vm = mm->hiwater_vm * PAGE_SIZE / KB; 96 stats->hiwater_vm = get_mm_hiwater_vm(mm) * PAGE_SIZE / KB;
97 mmput(mm); 97 mmput(mm);
98 } 98 }
99 stats->read_char = p->ioac.rchar; 99 stats->read_char = p->ioac.rchar;