From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id DBD116B004A for ; Sun, 7 Nov 2010 17:15:07 -0500 (EST) From: Johannes Weiner Subject: [patch 1/4] memcg: use native word to represent dirtyable pages Date: Sun, 7 Nov 2010 23:14:36 +0100 Message-Id: <20101107220353.115646194@cmpxchg.org> In-Reply-To: <20101107215030.007259800@cmpxchg.org> References: <20101107215030.007259800@cmpxchg.org> References: <1288973333-7891-1-git-send-email-minchan.kim@gmail.com> <20101106010357.GD23393@cmpxchg.org> <20101107215030.007259800@cmpxchg.org> Content-Disposition: inline; filename=memcg-use-native-word-to-represent-dirtyable-pages.patch Sender: owner-linux-mm@kvack.org To: Greg Thelen Cc: Minchan Kim , Andrew Morton , Dave Young , Andrea Righi , KAMEZAWA Hiroyuki , Daisuke Nishimura , Balbir Singh , Wu Fengguang , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: The memory cgroup dirty info calculation currently uses a signed 64-bit type to represent the amount of dirtyable memory in pages. This can instead be changed to an unsigned word, which will allow the formula to function correctly with up to 160G of LRU pages on a 32-bit system, assuming 4k pages. That should be plenty even when taking racy folding of the per-cpu counters into account. This fixes a compilation error on 32-bit systems as this code tries to do 64-bit division. Signed-off-by: Johannes Weiner Reported-by: Dave Young --- mm/memcontrol.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1222,9 +1222,10 @@ static void __mem_cgroup_dirty_param(str bool mem_cgroup_dirty_info(unsigned long sys_available_mem, struct dirty_info *info) { - s64 available_mem; struct vm_dirty_param dirty_param; + unsigned long available_mem; struct mem_cgroup *memcg; + s64 value; if (mem_cgroup_disabled()) return false; @@ -1238,11 +1239,11 @@ bool mem_cgroup_dirty_info(unsigned long __mem_cgroup_dirty_param(&dirty_param, memcg); rcu_read_unlock(); - available_mem = mem_cgroup_page_stat(MEMCG_NR_DIRTYABLE_PAGES); - if (available_mem < 0) + value = mem_cgroup_page_stat(MEMCG_NR_DIRTYABLE_PAGES); + if (value < 0) return false; - available_mem = min((unsigned long)available_mem, sys_available_mem); + available_mem = min((unsigned long)value, sys_available_mem); if (dirty_param.dirty_bytes) info->dirty_thresh = -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org