From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id 9EC326B0011 for ; Fri, 27 May 2011 00:49:19 -0400 (EDT) Received: from kpbe18.cbf.corp.google.com (kpbe18.cbf.corp.google.com [172.25.105.82]) by smtp-out.google.com with ESMTP id p4R4nFsP024134 for ; Thu, 26 May 2011 21:49:15 -0700 Received: from qwj8 (qwj8.prod.google.com [10.241.195.72]) by kpbe18.cbf.corp.google.com with ESMTP id p4R4n8rx015882 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Thu, 26 May 2011 21:49:14 -0700 Received: by qwj8 with SMTP id 8so1054940qwj.32 for ; Thu, 26 May 2011 21:49:13 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110527133431.471eefc2.kamezawa.hiroyu@jp.fujitsu.com> References: <20110526141047.dc828124.kamezawa.hiroyu@jp.fujitsu.com> <20110527111639.22e3e257.kamezawa.hiroyu@jp.fujitsu.com> <20110527133431.471eefc2.kamezawa.hiroyu@jp.fujitsu.com> Date: Thu, 26 May 2011 21:49:13 -0700 Message-ID: Subject: Re: [RFC][PATCH v3 0/10] memcg async reclaim From: Ying Han Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "nishimura@mxp.nes.nec.co.jp" , "balbir@linux.vnet.ibm.com" On Thu, May 26, 2011 at 9:34 PM, KAMEZAWA Hiroyuki wrote: > On Thu, 26 May 2011 21:33:32 -0700 > Ying Han wrote: > >> On Thu, May 26, 2011 at 7:16 PM, KAMEZAWA Hiroyuki >> wrote: >> > On Thu, 26 May 2011 18:49:26 -0700 >> > Ying Han wrote: >> > >> >> On Wed, May 25, 2011 at 10:10 PM, KAMEZAWA Hiroyuki >> >> wrote: >> >> > >> >> > It's now merge window...I just dump my patch queue to hear other's = idea. >> >> > I wonder I should wait until dirty_ratio for memcg is queued to mmo= tm... >> >> > I'll be busy with LinuxCon Japan etc...in the next week. >> >> > >> >> > This patch is onto mmotm-May-11 + some patches queued in mmotm, as = numa_stat. >> >> > >> >> > This is a patch for memcg to keep margin to the limit in background= . >> >> > By keeping some margin to the limit in background, application can >> >> > avoid foreground memory reclaim at charge() and this will help late= ncy. >> >> > >> >> > Main changes from v2 is. >> >> > =A0- use SCHED_IDLE. >> >> > =A0- removed most of heuristic codes. Now, code is very simple. >> >> > >> >> > By using SCHED_IDLE, async memory reclaim can only consume 0.3%? of= cpu >> >> > if the system is truely busy but can use much CPU if the cpu is idl= e. >> >> > Because my purpose is for reducing latency without affecting other = running >> >> > applications, SCHED_IDLE fits this work. >> >> > >> >> > If application need to stop by some I/O or event, background memory= reclaim >> >> > will cull memory while the system is idle. >> >> > >> >> > Perforemce: >> >> > =A0Running an httpd (apache) under 300M limit. And access 600MB wor= king set >> >> > =A0with normalized distribution access by apatch-bench. >> >> > =A0apatch bench's concurrency was 4 and did 40960 accesses. >> >> > >> >> > Without async reclaim: >> >> > Connection Times (ms) >> >> > =A0 =A0 =A0 =A0 =A0 =A0 =A0min =A0mean[+/-sd] median =A0 max >> >> > Connect: =A0 =A0 =A0 =A00 =A0 =A00 =A0 0.0 =A0 =A0 =A00 =A0 =A0 =A0= 2 >> >> > Processing: =A0 =A030 =A0 37 =A028.3 =A0 =A0 32 =A0 =A01793 >> >> > Waiting: =A0 =A0 =A0 28 =A0 35 =A025.5 =A0 =A0 31 =A0 =A01792 >> >> > Total: =A0 =A0 =A0 =A0 30 =A0 37 =A028.4 =A0 =A0 32 =A0 =A01793 >> >> > >> >> > Percentage of the requests served within a certain time (ms) >> >> > =A050% =A0 =A0 32 >> >> > =A066% =A0 =A0 32 >> >> > =A075% =A0 =A0 33 >> >> > =A080% =A0 =A0 34 >> >> > =A090% =A0 =A0 39 >> >> > =A095% =A0 =A0 60 >> >> > =A098% =A0 =A0100 >> >> > =A099% =A0 =A0133 >> >> > =A0100% =A0 1793 (longest request) >> >> > >> >> > With async reclaim: >> >> > Connection Times (ms) >> >> > =A0 =A0 =A0 =A0 =A0 =A0 =A0min =A0mean[+/-sd] median =A0 max >> >> > Connect: =A0 =A0 =A0 =A00 =A0 =A00 =A0 0.0 =A0 =A0 =A00 =A0 =A0 =A0= 2 >> >> > Processing: =A0 =A030 =A0 35 =A012.3 =A0 =A0 32 =A0 =A0 678 >> >> > Waiting: =A0 =A0 =A0 28 =A0 34 =A012.0 =A0 =A0 31 =A0 =A0 658 >> >> > Total: =A0 =A0 =A0 =A0 30 =A0 35 =A012.3 =A0 =A0 32 =A0 =A0 678 >> >> > >> >> > Percentage of the requests served within a certain time (ms) >> >> > =A050% =A0 =A0 32 >> >> > =A066% =A0 =A0 32 >> >> > =A075% =A0 =A0 33 >> >> > =A080% =A0 =A0 34 >> >> > =A090% =A0 =A0 39 >> >> > =A095% =A0 =A0 49 >> >> > =A098% =A0 =A0 71 >> >> > =A099% =A0 =A0 86 >> >> > =A0100% =A0 =A0678 (longest request) >> >> > >> >> > >> >> > It seems latency is stabilized by hiding memory reclaim. >> >> > >> >> > The score for memory reclaim was following. >> >> > See patch 10 for meaning of each member. >> >> > >> >> > =3D=3D without async reclaim =3D=3D >> >> > recent_scan_success_ratio 44 >> >> > limit_scan_pages 388463 >> >> > limit_freed_pages 162238 >> >> > limit_elapsed_ns 13852159231 >> >> > soft_scan_pages 0 >> >> > soft_freed_pages 0 >> >> > soft_elapsed_ns 0 >> >> > margin_scan_pages 0 >> >> > margin_freed_pages 0 >> >> > margin_elapsed_ns 0 >> >> > >> >> > =3D=3D with async reclaim =3D=3D >> >> > recent_scan_success_ratio 6 >> >> > limit_scan_pages 0 >> >> > limit_freed_pages 0 >> >> > limit_elapsed_ns 0 >> >> > soft_scan_pages 0 >> >> > soft_freed_pages 0 >> >> > soft_elapsed_ns 0 >> >> > margin_scan_pages 1295556 >> >> > margin_freed_pages 122450 >> >> > margin_elapsed_ns 644881521 >> >> > >> >> > >> >> > For this case, SCHED_IDLE workqueue can reclaim enough memory to th= e httpd. >> >> > >> >> > I may need to dig why scan_success_ratio is far different in the bo= th case. >> >> > I guess the difference of epalsed_ns is because several threads ent= er >> >> > memory reclaim when async reclaim doesn't run. But may not... >> >> > >> >> >> >> >> >> Hmm.. I noticed a very strange behavior on a simple test w/ the patch= set. >> >> >> >> Test: >> >> I created a 4g memcg and start doing cat. Then the memcg being OOM >> >> killed as soon as it reaches its hard_limit. We shouldn't hit OOM eve= n >> >> w/o async-reclaim. >> >> >> >> Again, I will read through the patch. But like to post the test resul= t first. >> >> >> >> $ echo $$ >/dev/cgroup/memory/A/tasks >> >> $ cat /dev/cgroup/memory/A/memory.limit_in_bytes >> >> 4294967296 >> >> >> >> $ time cat /export/hdc3/dd_A/tf0 > /dev/zero >> >> Killed >> >> >> > >> > I did the same kind of test without any problem...but ok, I'll do more= test >> > later. >> > >> > >> > >> >> real =A00m53.565s >> >> user =A00m0.061s >> >> sys =A0 0m4.814s >> >> >> >> Here is the OOM log: >> >> >> >> May 26 18:43:00 =A0kernel: [ =A0963.489112] cat invoked oom-killer: >> >> gfp_mask=3D0xd0, order=3D0, oom_adj=3D0, oom_score_adj=3D0 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489121] Pid: 9425, comm: cat Tain= ted: >> >> G =A0 =A0 =A0 =A0W =A0 2.6.39-mcg-DEV #131 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489123] Call Trace: >> >> May 26 18:43:00 =A0kernel: [ =A0963.489134] =A0[] >> >> dump_header+0x82/0x1af >> >> May 26 18:43:00 =A0kernel: [ =A0963.489137] =A0[] ? >> >> spin_lock+0xe/0x10 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489140] =A0[] ? >> >> find_lock_task_mm+0x2d/0x67 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489143] =A0[] >> >> oom_kill_process+0x50/0x27b >> >> May 26 18:43:00 =A0kernel: [ =A0963.489155] =A0[] >> >> mem_cgroup_out_of_memory+0x9a/0xe4 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489160] =A0[] >> >> mem_cgroup_handle_oom+0x134/0x1fe >> >> May 26 18:43:00 =A0kernel: [ =A0963.489163] =A0[] ? >> >> __mem_cgroup_insert_exceeded+0x83/0x83 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489176] =A0[] >> >> __mem_cgroup_try_charge.clone.3+0x368/0x43a >> >> May 26 18:43:00 =A0kernel: [ =A0963.489179] =A0[] >> >> mem_cgroup_cache_charge+0x95/0x123 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489183] =A0[] >> >> add_to_page_cache_locked+0x42/0x114 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489185] =A0[] >> >> add_to_page_cache_lru+0x31/0x5f >> >> May 26 18:43:00 =A0kernel: [ =A0963.489189] =A0[] >> >> mpage_readpages+0xb6/0x132 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489194] =A0[] ? >> >> noalloc_get_block_write+0x24/0x24 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489197] =A0[] ? >> >> noalloc_get_block_write+0x24/0x24 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489201] =A0[] ? >> >> __switch_to+0x160/0x212 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489205] =A0[] >> >> ext4_readpages+0x1d/0x1f >> >> May 26 18:43:00 =A0kernel: [ =A0963.489209] =A0[] >> >> __do_page_cache_readahead+0x144/0x1e3 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489212] =A0[] >> >> ra_submit+0x21/0x25 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489215] =A0[] >> >> ondemand_readahead+0x18c/0x19f >> >> May 26 18:43:00 =A0kernel: [ =A0963.489218] =A0[] >> >> page_cache_async_readahead+0x7d/0x86 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489221] =A0[] >> >> generic_file_aio_read+0x2d8/0x5fe >> >> May 26 18:43:00 =A0kernel: [ =A0963.489225] =A0[] >> >> do_sync_read+0xcb/0x108 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489230] =A0[] ? >> >> fsnotify_perm+0x66/0x72 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489233] =A0[] ? >> >> security_file_permission+0x2e/0x33 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489236] =A0[] >> >> vfs_read+0xab/0x107 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489239] =A0[] s= ys_read+0x4a/0x6e >> >> May 26 18:43:00 =A0kernel: [ =A0963.489244] =A0[] >> >> sysenter_dispatch+0x7/0x27 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489248] Task in /A killed as a re= sult >> >> of limit of /A >> >> May 26 18:43:00 =A0kernel: [ =A0963.489251] memory: usage 4194304kB, = limit >> >> 4194304kB, failcnt 26 >> >> May 26 18:43:00 =A0kernel: [ =A0963.489253] memory+swap: usage 0kB, l= imit >> >> 9007199254740991kB, failcnt 0 >> >> >> > >> > Hmm, why memory+swap usage 0kb here... >> > >> > In this set, I used mem_cgroup_margin() rather than res_counter_margin= (). >> > Hmm, do you disable swap accounting ? If so, I may miss some. >> >> Yes, I disabled the swap accounting in .config: >> # CONFIG_CGROUP_MEM_RES_CTLR_SWAP is not set >> >> >> Here is how i reproduce it: >> >> $ mkdir /dev/cgroup/memory/D >> $ echo 4g >/dev/cgroup/memory/D/memory.limit_in_bytes >> >> $ cat /dev/cgroup/memory/D/memory.limit_in_bytes >> 4294967296 >> >> $ cat /dev/cgroup/memory/D/memory. >> memory.async_control =A0 =A0 =A0 =A0 =A0 =A0 memory.max_usage_in_bytes >> memory.soft_limit_in_bytes =A0 =A0 =A0 memory.use_hierarchy >> memory.failcnt =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 memory.move_charge_at= _immigrate >> memory.stat >> memory.force_empty =A0 =A0 =A0 =A0 =A0 =A0 =A0 memory.oom_control >> memory.swappiness >> memory.limit_in_bytes =A0 =A0 =A0 =A0 =A0 =A0memory.reclaim_stat >> memory.usage_in_bytes >> >> $ cat /dev/cgroup/memory/D/memory.async_control >> 0 >> $ echo 1 >/dev/cgroup/memory/D/memory.async_control >> $ cat /dev/cgroup/memory/D/memory.async_control >> 1 >> >> $ echo $$ >/dev/cgroup/memory/D/tasks >> $ cat /proc/4358/cgroup >> 3:memory:/D >> >> $ time cat /export/hdc3/dd_A/tf0 > /dev/zero >> Killed >> > > If you applied my patches collectly, async_control can be seen if > swap controller is configured because of BUG in patch. I noticed the BUG at the very beginning, so all my tests are having the fix= . > > I could cat 20G file under 4G limit without any problem with boot option > swapaccount=3D0. no problem if async_control =3D=3D 0 ? $ cat /dev/cgroup/memory/D/memory.async_control 1 I have the .config # CONFIG_CGROUP_MEM_RES_CTLR_SWAP is not set Not sure if that makes difference. I will test next to turn that on. --Ying > > > > Thanks, > -Kame > > > > -- 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 internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org