From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx207.postini.com [74.125.245.207]) by kanga.kvack.org (Postfix) with SMTP id 1CF106B0071 for ; Wed, 4 Jul 2012 09:19:53 -0400 (EDT) Received: by ggm4 with SMTP id 4so7942802ggm.14 for ; Wed, 04 Jul 2012 06:19:52 -0700 (PDT) Date: Wed, 4 Jul 2012 21:19:42 +0800 From: Wanpeng Li Subject: Re: [RFC][PATCH 1/2] add res_counter_usage_safe Message-ID: <20120704131941.GA21100@kernel> Reply-To: Wanpeng Li References: <4FEC300A.7040209@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4FEC300A.7040209@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org List-ID: To: Kamezawa Hiroyuki Cc: linux-mm , Michal Hocko , David Rientjes , Johannes Weiner , Andrew Morton , Tejun Heo , Wanpeng Li On Thu, Jun 28, 2012 at 07:20:58PM +0900, Kamezawa Hiroyuki wrote: >This series is a cleaned up patches discussed in a few days ago, the topic >was how to make compaction works well even if there is a memcg under OOM. >== >memcg: add res_counter_usage_safe() > >I think usage > limit means a sign of BUG. But, sometimes, >res_counter_charge_nofail() is very convenient. tcp_memcg uses it. >And I'd like to use it for helping page migration. > >This patch adds res_counter_usage_safe() which returns min(usage,limit). >By this we can use res_counter_charge_nofail() without breaking >user experience. > >Signed-off-by: KAMEZAWA Hiroyuki >--- > include/linux/res_counter.h | 2 ++ > kernel/res_counter.c | 15 +++++++++++++++ > net/ipv4/tcp_memcontrol.c | 2 +- > 3 files changed, 18 insertions(+), 1 deletions(-) > >diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h >index 7d7fbe2..a6f8cc5 100644 >--- a/include/linux/res_counter.h >+++ b/include/linux/res_counter.h >@@ -226,4 +226,6 @@ res_counter_set_soft_limit(struct res_counter *cnt, > return 0; > } > >+u64 res_counter_usage_safe(struct res_counter *cnt); >+ > #endif >diff --git a/kernel/res_counter.c b/kernel/res_counter.c >index ad581aa..e84149b 100644 >--- a/kernel/res_counter.c >+++ b/kernel/res_counter.c >@@ -171,6 +171,21 @@ u64 res_counter_read_u64(struct res_counter *counter, int member) > } > #endif > >+/* >+ * Returns usage. If usage > limit, limit is returned. >+ * This is useful not to break user experiance if the excess ^^^^^^^^ /experiance/experience >+ * is temporal. >+ */ >+u64 res_counter_usage_safe(struct res_counter *counter) >+{ >+ u64 usage, limit; >+ >+ limit = res_counter_read_u64(counter, RES_LIMIT); >+ usage = res_counter_read_u64(counter, RES_USAGE); >+ >+ return min(usage, limit); >+} >+ > int res_counter_memparse_write_strategy(const char *buf, > unsigned long long *res) > { >diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c >index b6f3583..a73dce6 100644 >--- a/net/ipv4/tcp_memcontrol.c >+++ b/net/ipv4/tcp_memcontrol.c >@@ -180,7 +180,7 @@ static u64 tcp_read_usage(struct mem_cgroup *memcg) > return atomic_long_read(&tcp_memory_allocated) << PAGE_SHIFT; > > tcp = tcp_from_cgproto(cg_proto); >- return res_counter_read_u64(&tcp->tcp_memory_allocated, RES_USAGE); >+ return res_counter_usage_safe(&tcp->tcp_memory_allocated); > } > > static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft) >-- >1.7.4.1 > > >-- >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/ . >Don't email: email@kvack.org -- 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/ . Don't email: email@kvack.org