Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754639Ab0KOJmy (ORCPT ); Mon, 15 Nov 2010 04:42:54 -0500 Received: from gir.skynet.ie ([193.1.99.77]:34055 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752235Ab0KOJmy (ORCPT ); Mon, 15 Nov 2010 04:42:54 -0500 Date: Mon, 15 Nov 2010 09:42:40 +0000 From: Mel Gorman To: KOSAKI Motohiro Cc: LKML , linux-mm , Andrew Morton Subject: Re: [PATCH] cleanup kswapd() Message-ID: <20101115094239.GH27362@csn.ul.ie> References: <20101114180505.BEE2.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20101114180505.BEE2.A69D9226@jp.fujitsu.com> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4542 Lines: 145 On Sun, Nov 14, 2010 at 06:05:26PM +0900, KOSAKI Motohiro wrote: > > Currently, kswapd() function has deeper nest and it slightly harder to > read. cleanup it. > > Cc: Mel Gorman > Signed-off-by: KOSAKI Motohiro > --- > mm/vmscan.c | 71 +++++++++++++++++++++++++++++++--------------------------- > 1 files changed, 38 insertions(+), 33 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 8cc90d5..82ffe5f 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -2364,6 +2364,42 @@ out: > return sc.nr_reclaimed; > } > > +void kswapd_try_to_sleep(pg_data_t *pgdat, int order) > +{ As pointed out elsewhere, this should be static. > + long remaining = 0; > + DEFINE_WAIT(wait); > + > + if (freezing(current) || kthread_should_stop()) > + return; > + > + prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); > + > + /* Try to sleep for a short interval */ > + if (!sleeping_prematurely(pgdat, order, remaining)) { > + remaining = schedule_timeout(HZ/10); > + finish_wait(&pgdat->kswapd_wait, &wait); > + prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); > + } > + > + /* > + * After a short sleep, check if it was a > + * premature sleep. If not, then go fully > + * to sleep until explicitly woken up > + */ Very minor but that comment should now fit on fewer lines. > + if (!sleeping_prematurely(pgdat, order, remaining)) { > + trace_mm_vmscan_kswapd_sleep(pgdat->node_id); > + set_pgdat_percpu_threshold(pgdat, calculate_normal_threshold); > + schedule(); > + set_pgdat_percpu_threshold(pgdat, calculate_pressure_threshold); I posted a patch adding a comment on why set_pgdat_percpu_threshold() is called. I do not believe it has been picked up by Andrew but it if is, the patches will conflict. The resolution will be obvious but you may need to respin this patch if the comment patch gets picked up in mmotm. Otherwise, I see no problems. > + } else { > + if (remaining) > + count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); > + else > + count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY); > + } > + finish_wait(&pgdat->kswapd_wait, &wait); > +} > + > /* > * The background pageout daemon, started as a kernel thread > * from the init process. > @@ -2382,7 +2418,7 @@ static int kswapd(void *p) > unsigned long order; > pg_data_t *pgdat = (pg_data_t*)p; > struct task_struct *tsk = current; > - DEFINE_WAIT(wait); > + > struct reclaim_state reclaim_state = { > .reclaimed_slab = 0, > }; > @@ -2414,7 +2450,6 @@ static int kswapd(void *p) > unsigned long new_order; > int ret; > > - prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); > new_order = pgdat->kswapd_max_order; > pgdat->kswapd_max_order = 0; > if (order < new_order) { > @@ -2424,39 +2459,9 @@ static int kswapd(void *p) > */ > order = new_order; > } else { > - if (!freezing(current) && !kthread_should_stop()) { > - long remaining = 0; > - > - /* Try to sleep for a short interval */ > - if (!sleeping_prematurely(pgdat, order, remaining)) { > - remaining = schedule_timeout(HZ/10); > - finish_wait(&pgdat->kswapd_wait, &wait); > - prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); > - } > - > - /* > - * After a short sleep, check if it was a > - * premature sleep. If not, then go fully > - * to sleep until explicitly woken up > - */ > - if (!sleeping_prematurely(pgdat, order, remaining)) { > - trace_mm_vmscan_kswapd_sleep(pgdat->node_id); > - set_pgdat_percpu_threshold(pgdat, > - calculate_normal_threshold); > - schedule(); > - set_pgdat_percpu_threshold(pgdat, > - calculate_pressure_threshold); > - } else { > - if (remaining) > - count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); > - else > - count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY); > - } > - } > - > + kswapd_try_to_sleep(pgdat, order); > order = pgdat->kswapd_max_order; > } > - finish_wait(&pgdat->kswapd_wait, &wait); > > ret = try_to_freeze(); > if (kthread_should_stop()) > -- > 1.6.5.2 > > > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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/