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Date: Wed, 3 Dec 2008 19:12:20 +0100 From: Oleg Nesterov <oleg@...hat.com> To: Andrew Morton <akpm@...ux-foundation.org> Cc: Balbir Singh <balbir@...ux.vnet.ibm.com>, Hugh Dickins <hugh@...itas.com>, Jay Lan <jlan@....com>, Jiri Pirko <jpirko@...hat.com>, linux-kernel@...r.kernel.org Subject: [PATCH] introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting Unless we are going to decrease rss/vm there is no point to call the (racy) update_hiwater_xxx() helpers. Still do_exit() does this, and the accounting code uses mm->hiwater_xxx directly. This is not right. fill_pid()->xacct_add_tsk() can be called by taskstats_user_cmd() at any time, not only when the task exits. in that case taskstats->hiwater_xxx can be very wrong. Introduce get_mm_hiwater_rss() and get_mm_hiwater_vm() to use instead, and kill the "if (tsk->mm) {}" code in do_exit(). The first helper will be also used to actually fill/report rusage->ru_maxrss. Signed-off-by: Oleg Nesterov <oleg@...hat.com> --- K-28/include/linux/sched.h~HIWATER 2008-12-02 17:12:40.000000000 +0100 +++ K-28/include/linux/sched.h 2008-12-03 18:17:18.000000000 +0100 @@ -388,6 +388,9 @@ extern void arch_unmap_area_topdown(stru (mm)->hiwater_vm = (mm)->total_vm; \ } while (0) +#define get_mm_hiwater_rss(mm) max((mm)->hiwater_rss, get_mm_rss(mm)) +#define get_mm_hiwater_vm(mm) max((mm)->hiwater_vm, (mm)->total_vm) + extern void set_dumpable(struct mm_struct *mm, int value); extern int get_dumpable(struct mm_struct *mm); --- K-28/kernel/tsacct.c~HIWATER 2008-10-10 00:13:53.000000000 +0200 +++ K-28/kernel/tsacct.c 2008-12-03 18:24:28.000000000 +0100 @@ -90,8 +90,8 @@ void xacct_add_tsk(struct taskstats *sta 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; --- K-28/kernel/exit.c~HIWATER 2008-12-02 17:12:40.000000000 +0100 +++ K-28/kernel/exit.c 2008-12-03 18:21:06.000000000 +0100 @@ -1048,10 +1048,7 @@ 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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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