Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751411Ab1E0Edl (ORCPT ); Fri, 27 May 2011 00:33:41 -0400 Received: from smtp-out.google.com ([74.125.121.67]:21912 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750777Ab1E0Edk convert rfc822-to-8bit (ORCPT ); Fri, 27 May 2011 00:33:40 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=dgdBllGM23PLuBK5x6qY3d9ps380qgaLHX+f8OemugsOIbzMtNXob9OsaXbNaFwDjW VdxflgL8BAmLF+E0lYrw== MIME-Version: 1.0 In-Reply-To: <20110527111639.22e3e257.kamezawa.hiroyu@jp.fujitsu.com> References: <20110526141047.dc828124.kamezawa.hiroyu@jp.fujitsu.com> <20110527111639.22e3e257.kamezawa.hiroyu@jp.fujitsu.com> Date: Thu, 26 May 2011 21:33:32 -0700 Message-ID: Subject: Re: [RFC][PATCH v3 0/10] memcg async reclaim From: Ying Han 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" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9106 Lines: 262 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 mmotm... >> > 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 latency. >> > >> > Main changes from v2 is. >> > ?- use SCHED_IDLE. >> > ?- 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 idle. >> > 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: >> > ?Running an httpd (apache) under 300M limit. And access 600MB working set >> > ?with normalized distribution access by apatch-bench. >> > ?apatch bench's concurrency was 4 and did 40960 accesses. >> > >> > Without async reclaim: >> > Connection Times (ms) >> > ? ? ? ? ? ? ?min ?mean[+/-sd] median ? max >> > Connect: ? ? ? ?0 ? ?0 ? 0.0 ? ? ?0 ? ? ? 2 >> > Processing: ? ?30 ? 37 ?28.3 ? ? 32 ? ?1793 >> > Waiting: ? ? ? 28 ? 35 ?25.5 ? ? 31 ? ?1792 >> > Total: ? ? ? ? 30 ? 37 ?28.4 ? ? 32 ? ?1793 >> > >> > Percentage of the requests served within a certain time (ms) >> > ?50% ? ? 32 >> > ?66% ? ? 32 >> > ?75% ? ? 33 >> > ?80% ? ? 34 >> > ?90% ? ? 39 >> > ?95% ? ? 60 >> > ?98% ? ?100 >> > ?99% ? ?133 >> > ?100% ? 1793 (longest request) >> > >> > With async reclaim: >> > Connection Times (ms) >> > ? ? ? ? ? ? ?min ?mean[+/-sd] median ? max >> > Connect: ? ? ? ?0 ? ?0 ? 0.0 ? ? ?0 ? ? ? 2 >> > Processing: ? ?30 ? 35 ?12.3 ? ? 32 ? ? 678 >> > Waiting: ? ? ? 28 ? 34 ?12.0 ? ? 31 ? ? 658 >> > Total: ? ? ? ? 30 ? 35 ?12.3 ? ? 32 ? ? 678 >> > >> > Percentage of the requests served within a certain time (ms) >> > ?50% ? ? 32 >> > ?66% ? ? 32 >> > ?75% ? ? 33 >> > ?80% ? ? 34 >> > ?90% ? ? 39 >> > ?95% ? ? 49 >> > ?98% ? ? 71 >> > ?99% ? ? 86 >> > ?100% ? ?678 (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. >> > >> > == without async reclaim == >> > 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 >> > >> > == with async reclaim == >> > 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 the httpd. >> > >> > I may need to dig why scan_success_ratio is far different in the both case. >> > I guess the difference of epalsed_ns is because several threads enter >> > 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 even >> w/o async-reclaim. >> >> Again, I will read through the patch. But like to post the test result 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 ?0m53.565s >> user ?0m0.061s >> sys ? 0m4.814s >> >> Here is the OOM log: >> >> May 26 18:43:00 ?kernel: [ ?963.489112] cat invoked oom-killer: >> gfp_mask=0xd0, order=0, oom_adj=0, oom_score_adj=0 >> May 26 18:43:00 ?kernel: [ ?963.489121] Pid: 9425, comm: cat Tainted: >> G ? ? ? ?W ? 2.6.39-mcg-DEV #131 >> May 26 18:43:00 ?kernel: [ ?963.489123] Call Trace: >> May 26 18:43:00 ?kernel: [ ?963.489134] ?[] >> dump_header+0x82/0x1af >> May 26 18:43:00 ?kernel: [ ?963.489137] ?[] ? >> spin_lock+0xe/0x10 >> May 26 18:43:00 ?kernel: [ ?963.489140] ?[] ? >> find_lock_task_mm+0x2d/0x67 >> May 26 18:43:00 ?kernel: [ ?963.489143] ?[] >> oom_kill_process+0x50/0x27b >> May 26 18:43:00 ?kernel: [ ?963.489155] ?[] >> mem_cgroup_out_of_memory+0x9a/0xe4 >> May 26 18:43:00 ?kernel: [ ?963.489160] ?[] >> mem_cgroup_handle_oom+0x134/0x1fe >> May 26 18:43:00 ?kernel: [ ?963.489163] ?[] ? >> __mem_cgroup_insert_exceeded+0x83/0x83 >> May 26 18:43:00 ?kernel: [ ?963.489176] ?[] >> __mem_cgroup_try_charge.clone.3+0x368/0x43a >> May 26 18:43:00 ?kernel: [ ?963.489179] ?[] >> mem_cgroup_cache_charge+0x95/0x123 >> May 26 18:43:00 ?kernel: [ ?963.489183] ?[] >> add_to_page_cache_locked+0x42/0x114 >> May 26 18:43:00 ?kernel: [ ?963.489185] ?[] >> add_to_page_cache_lru+0x31/0x5f >> May 26 18:43:00 ?kernel: [ ?963.489189] ?[] >> mpage_readpages+0xb6/0x132 >> May 26 18:43:00 ?kernel: [ ?963.489194] ?[] ? >> noalloc_get_block_write+0x24/0x24 >> May 26 18:43:00 ?kernel: [ ?963.489197] ?[] ? >> noalloc_get_block_write+0x24/0x24 >> May 26 18:43:00 ?kernel: [ ?963.489201] ?[] ? >> __switch_to+0x160/0x212 >> May 26 18:43:00 ?kernel: [ ?963.489205] ?[] >> ext4_readpages+0x1d/0x1f >> May 26 18:43:00 ?kernel: [ ?963.489209] ?[] >> __do_page_cache_readahead+0x144/0x1e3 >> May 26 18:43:00 ?kernel: [ ?963.489212] ?[] >> ra_submit+0x21/0x25 >> May 26 18:43:00 ?kernel: [ ?963.489215] ?[] >> ondemand_readahead+0x18c/0x19f >> May 26 18:43:00 ?kernel: [ ?963.489218] ?[] >> page_cache_async_readahead+0x7d/0x86 >> May 26 18:43:00 ?kernel: [ ?963.489221] ?[] >> generic_file_aio_read+0x2d8/0x5fe >> May 26 18:43:00 ?kernel: [ ?963.489225] ?[] >> do_sync_read+0xcb/0x108 >> May 26 18:43:00 ?kernel: [ ?963.489230] ?[] ? >> fsnotify_perm+0x66/0x72 >> May 26 18:43:00 ?kernel: [ ?963.489233] ?[] ? >> security_file_permission+0x2e/0x33 >> May 26 18:43:00 ?kernel: [ ?963.489236] ?[] >> vfs_read+0xab/0x107 >> May 26 18:43:00 ?kernel: [ ?963.489239] ?[] sys_read+0x4a/0x6e >> May 26 18:43:00 ?kernel: [ ?963.489244] ?[] >> sysenter_dispatch+0x7/0x27 >> May 26 18:43:00 ?kernel: [ ?963.489248] Task in /A killed as a result >> of limit of /A >> May 26 18:43:00 ?kernel: [ ?963.489251] memory: usage 4194304kB, limit >> 4194304kB, failcnt 26 >> May 26 18:43:00 ?kernel: [ ?963.489253] memory+swap: usage 0kB, limit >> 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 memory.max_usage_in_bytes memory.soft_limit_in_bytes memory.use_hierarchy memory.failcnt memory.move_charge_at_immigrate memory.stat memory.force_empty memory.oom_control memory.swappiness memory.limit_in_bytes memory.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 --Ying > > Thanks, > -Kame > > > > > -- 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/