Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758174AbYFDCik (ORCPT ); Tue, 3 Jun 2008 22:38:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756335AbYFDCiT (ORCPT ); Tue, 3 Jun 2008 22:38:19 -0400 Received: from gateway-1237.mvista.com ([63.81.120.158]:27558 "EHLO gateway-1237.mvista.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757633AbYFDCiQ (ORCPT ); Tue, 3 Jun 2008 22:38:16 -0400 Date: Tue, 3 Jun 2008 19:38:25 -0700 From: Keika Kobayashi To: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org Subject: [PATCH 1/4] per-task-delay-accounting: add memory reclaim delay Message-Id: <20080603193825.12dbfff1.kobayashi.kk@ncos.nec.co.jp> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6336 Lines: 196 Sometimes, application responses become bad under heavy memory load. Applications take a bit time to reclaim memory. The statistics, how long memory reclaim takes, will be useful to measure memory usage. This patch adds accounting memory reclaim to per-task-delay-accounting for accounting the time of try_to_free_pages(). - When System is under low memory load, memory reclaim may not occur. $ free total used free shared buffers cached Mem: 8197800 1577300 6620500 0 4808 1516724 -/+ buffers/cache: 55768 8142032 Swap: 16386292 0 16386292 $ vmstat 1 procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 0 5069748 10612 3014060 0 0 0 0 3 26 0 0 100 0 0 0 0 5069748 10612 3014060 0 0 0 0 4 22 0 0 100 0 0 0 0 5069748 10612 3014060 0 0 0 0 3 18 0 0 100 0 Measure the time of tar command. $ ls -s test.dat 1501472 test.dat $ time tar cvf test.tar test.dat real 0m13.388s user 0m0.116s sys 0m5.304s $ ./delayget -d -p CPU count real total virtual total delay total 428 5528345500 5477116080 62749891 IO count delay total 338 8078977189 SWAP count delay total 0 0 RECLAIM count delay total 0 0 - When system is under heavy memory load memory reclaim may occur. $ vmstat 1 procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 7159032 49724 1812 3012 0 0 0 0 3 24 0 0 100 0 0 0 7159032 49724 1812 3012 0 0 0 0 4 24 0 0 100 0 0 0 7159032 49848 1812 3012 0 0 0 0 3 22 0 0 100 0 In this case, one process uses more 8G memory by execution of malloc() and memset(). $ time tar cvf test.tar test.dat real 1m38.563s <- increased by 85 sec user 0m0.140s sys 0m7.060s $ ./delayget -d -p CPU count real total virtual total delay total 9021 7140446250 7315277975 923201824 IO count delay total 8965 90466349669 SWAP count delay total 3 21036367 RECLAIM count delay total 740 61011951153 In the later case, the value of RECLAIM is increasing. So, taskstats can show how much memory reclaim influences TAT. Signed-off-by: Keika Kobayashi --- include/linux/delayacct.h | 19 +++++++++++++++++++ include/linux/sched.h | 4 ++++ kernel/delayacct.c | 13 +++++++++++++ mm/page_alloc.c | 3 +++ 4 files changed, 39 insertions(+), 0 deletions(-) diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h index ab94bc0..f352f06 100644 --- a/include/linux/delayacct.h +++ b/include/linux/delayacct.h @@ -39,6 +39,8 @@ extern void __delayacct_blkio_start(void); extern void __delayacct_blkio_end(void); extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *); extern __u64 __delayacct_blkio_ticks(struct task_struct *); +extern void __delayacct_freepages_start(void); +extern void __delayacct_freepages_end(void); static inline int delayacct_is_task_waiting_on_io(struct task_struct *p) { @@ -107,6 +109,18 @@ static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk) return 0; } +static inline void delayacct_freepages_start(void) +{ + if (current->delays) + __delayacct_freepages_start(); +} + +static inline void delayacct_freepages_end(void) +{ + if (current->delays) + __delayacct_freepages_end(); +} + #else static inline void delayacct_set_flag(int flag) {} @@ -129,6 +143,11 @@ static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk) { return 0; } static inline int delayacct_is_task_waiting_on_io(struct task_struct *p) { return 0; } +static inline void delayacct_freepages_start(void) +{} +static inline void delayacct_freepages_end(void) +{} + #endif /* CONFIG_TASK_DELAY_ACCT */ #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index 3e05e54..e6c557c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -666,6 +666,10 @@ struct task_delay_info { /* io operations performed */ u32 swapin_count; /* total count of the number of swapin block */ /* io operations performed */ + + struct timespec freepages_start, freepages_end; + u64 freepages_delay; /* wait for memory reclaim */ + u32 freepages_count; /* total count of memory reclaim */ }; #endif /* CONFIG_TASK_DELAY_ACCT */ diff --git a/kernel/delayacct.c b/kernel/delayacct.c index 10e43fd..84b6782 100644 --- a/kernel/delayacct.c +++ b/kernel/delayacct.c @@ -165,3 +165,16 @@ __u64 __delayacct_blkio_ticks(struct task_struct *tsk) return ret; } +void __delayacct_freepages_start(void) +{ + delayacct_start(¤t->delays->freepages_start); +} + +void __delayacct_freepages_end(void) +{ + delayacct_end(¤t->delays->freepages_start, + ¤t->delays->freepages_end, + ¤t->delays->freepages_delay, + ¤t->delays->freepages_count); +} + diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 8e83f02..8b4e606 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -46,6 +46,7 @@ #include #include #include +#include #include #include @@ -1571,7 +1572,9 @@ nofail_alloc: reclaim_state.reclaimed_slab = 0; p->reclaim_state = &reclaim_state; + delayacct_freepages_start(); did_some_progress = try_to_free_pages(zonelist, order, gfp_mask); + delayacct_freepages_end(); p->reclaim_state = NULL; p->flags &= ~PF_MEMALLOC; -- 1.5.0.6 -- 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/