Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753303AbZIEV0L (ORCPT ); Sat, 5 Sep 2009 17:26:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751152AbZIEV0K (ORCPT ); Sat, 5 Sep 2009 17:26:10 -0400 Received: from mk-filter-1-a-1.mail.uk.tiscali.com ([212.74.100.52]:40108 "EHLO mk-filter-1-a-1.mail.uk.tiscali.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751089AbZIEV0J (ORCPT ); Sat, 5 Sep 2009 17:26:09 -0400 X-Trace: 258213545/mk-filter-1.mail.uk.tiscali.com/B2C/$b2c-THROTTLED-DYNAMIC/b2c-CUSTOMER-DYNAMIC-IP/79.69.92.10/None/hugh.dickins@tiscali.co.uk X-SBRS: None X-RemoteIP: 79.69.92.10 X-IP-MAIL-FROM: hugh.dickins@tiscali.co.uk X-SMTP-AUTH: X-MUA: X-IP-BHB: Once X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Aq8EAJRzokpPRVwK/2dsb2JhbACBU9Y7hBgF X-IronPort-AV: E=Sophos;i="4.44,339,1249254000"; d="scan'208";a="258213545" Date: Sat, 5 Sep 2009 22:25:21 +0100 (BST) From: Hugh Dickins X-X-Sender: hugh@sister.anvils To: Andrew Morton cc: Izik Eidus , Andrea Arcangeli , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 2/3] ksm: unmerge is an origin of OOMs In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3055 Lines: 73 Just as the swapoff system call allocates many pages of RAM to various processes, perhaps triggering OOM, so "echo 2 >/sys/kernel/mm/ksm/run" (unmerge) is liable to allocate many pages of RAM to various processes, perhaps triggering OOM; and each is normally run from a modest admin process (swapoff or shell), easily repeated until it succeeds. So treat unmerge_and_remove_all_rmap_items() in the same way that we treat try_to_unuse(): generalize PF_SWAPOFF to PF_OOM_ORIGIN, and bracket both with that, to ask the OOM killer to kill them first, to prevent them from spawning more and more OOM kills. Signed-off-by: Hugh Dickins --- include/linux/sched.h | 2 +- mm/ksm.c | 2 ++ mm/oom_kill.c | 2 +- mm/swapfile.c | 4 ++-- 4 files changed, 6 insertions(+), 4 deletions(-) --- mmotm/include/linux/sched.h 2009-09-05 14:40:16.000000000 +0100 +++ linux/include/linux/sched.h 2009-09-05 16:41:55.000000000 +0100 @@ -1755,7 +1755,7 @@ extern cputime_t task_gtime(struct task_ #define PF_FROZEN 0x00010000 /* frozen for system suspend */ #define PF_FSTRANS 0x00020000 /* inside a filesystem transaction */ #define PF_KSWAPD 0x00040000 /* I am kswapd */ -#define PF_SWAPOFF 0x00080000 /* I am in swapoff */ +#define PF_OOM_ORIGIN 0x00080000 /* Allocating much memory to others */ #define PF_LESS_THROTTLE 0x00100000 /* Throttle me less: I clean memory */ #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ #define PF_RANDOMIZE 0x00400000 /* randomize virtual address space */ --- mmotm/mm/ksm.c 2009-09-05 14:40:16.000000000 +0100 +++ linux/mm/ksm.c 2009-09-05 16:41:55.000000000 +0100 @@ -1564,7 +1564,9 @@ static ssize_t run_store(struct kobject if (ksm_run != flags) { ksm_run = flags; if (flags & KSM_RUN_UNMERGE) { + current->flags |= PF_OOM_ORIGIN; err = unmerge_and_remove_all_rmap_items(); + current->flags &= ~PF_OOM_ORIGIN; if (err) { ksm_run = KSM_RUN_STOP; count = err; --- mmotm/mm/oom_kill.c 2009-09-05 14:40:16.000000000 +0100 +++ linux/mm/oom_kill.c 2009-09-05 16:41:55.000000000 +0100 @@ -103,7 +103,7 @@ unsigned long badness(struct task_struct /* * swapoff can easily use up all memory, so kill those first. */ - if (p->flags & PF_SWAPOFF) + if (p->flags & PF_OOM_ORIGIN) return ULONG_MAX; /* --- mmotm/mm/swapfile.c 2009-09-05 14:40:16.000000000 +0100 +++ linux/mm/swapfile.c 2009-09-05 16:41:55.000000000 +0100 @@ -1573,9 +1573,9 @@ SYSCALL_DEFINE1(swapoff, const char __us p->flags &= ~SWP_WRITEOK; spin_unlock(&swap_lock); - current->flags |= PF_SWAPOFF; + current->flags |= PF_OOM_ORIGIN; err = try_to_unuse(type); - current->flags &= ~PF_SWAPOFF; + current->flags &= ~PF_OOM_ORIGIN; if (err) { /* re-insert swap space back into swap_list */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/