The patch titled mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting has been removed from the -mm tree. Its filename was introduce-get_mm_hiwater_xxx-fix-taskstats-hiwater_xxx-accounting.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting From: Oleg Nesterov <oleg@xxxxxxxxxx> 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@xxxxxxxxxx> Acked-by: Hugh Dickins <hugh@xxxxxxxxxxx> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Acked-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/sched.h | 3 +++ kernel/exit.c | 5 +---- kernel/tsacct.c | 4 ++-- mm/mmap.c | 2 +- 4 files changed, 7 insertions(+), 7 deletions(-) diff -puN include/linux/sched.h~introduce-get_mm_hiwater_xxx-fix-taskstats-hiwater_xxx-accounting include/linux/sched.h --- a/include/linux/sched.h~introduce-get_mm_hiwater_xxx-fix-taskstats-hiwater_xxx-accounting +++ a/include/linux/sched.h @@ -386,6 +386,9 @@ 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); diff -puN kernel/exit.c~introduce-get_mm_hiwater_xxx-fix-taskstats-hiwater_xxx-accounting kernel/exit.c --- a/kernel/exit.c~introduce-get_mm_hiwater_xxx-fix-taskstats-hiwater_xxx-accounting +++ a/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 -puN kernel/tsacct.c~introduce-get_mm_hiwater_xxx-fix-taskstats-hiwater_xxx-accounting kernel/tsacct.c --- a/kernel/tsacct.c~introduce-get_mm_hiwater_xxx-fix-taskstats-hiwater_xxx-accounting +++ a/kernel/tsacct.c @@ -92,8 +92,8 @@ 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; diff -puN mm/mmap.c~introduce-get_mm_hiwater_xxx-fix-taskstats-hiwater_xxx-accounting mm/mmap.c --- a/mm/mmap.c~introduce-get_mm_hiwater_xxx-fix-taskstats-hiwater_xxx-accounting +++ a/mm/mmap.c @@ -2102,7 +2102,7 @@ void exit_mmap(struct mm_struct *mm) lru_add_drain(); flush_cache_mm(mm); tlb = tlb_gather_mmu(mm, 1); - /* Don't update_hiwater_rss(mm) here, do_exit already did */ + /* update_hiwater_rss(mm) here? but nobody should be looking */ /* Use -1 here to ensure all VMAs in the mm are unmapped */ end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); vm_unacct_memory(nr_accounted); _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are origin.patch linux-next.patch getrusage-fill-ru_maxrss-value.patch pid-implement-ns_of_pid.patch pid-generalize-task_active_pid_ns.patch mqueue-fix-si_pid-value-in-mqueue-do_notify.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html