From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id B00CE6B0047 for ; Tue, 21 Apr 2009 05:47:04 -0400 (EDT) Date: Tue, 21 Apr 2009 10:47:45 +0100 From: Mel Gorman Subject: Re: [PATCH 07/25] Check in advance if the zonelist needs additional filtering Message-ID: <20090421094745.GL12713@csn.ul.ie> References: <1240266011-11140-1-git-send-email-mel@csn.ul.ie> <1240266011-11140-8-git-send-email-mel@csn.ul.ie> <20090421155038.F130.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20090421155038.F130.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Linux Memory Management List , Christoph Lameter , Nick Piggin , Linux Kernel Mailing List , Lin Ming , Zhang Yanmin , Peter Zijlstra , Pekka Enberg , Andrew Morton List-ID: On Tue, Apr 21, 2009 at 03:52:48PM +0900, KOSAKI Motohiro wrote: > > Zonelist are filtered based on nodemasks for memory policies normally. > > It can be additionally filters on cpusets if they exist as well as > > noting when zones are full. These simple checks are expensive enough to > > be noticed in profiles. This patch checks in advance if zonelist > > filtering will ever be needed. If not, then the bulk of the checks are > > skipped. > > > > Signed-off-by: Mel Gorman > > --- > > include/linux/cpuset.h | 2 ++ > > mm/page_alloc.c | 37 ++++++++++++++++++++++++++----------- > > 2 files changed, 28 insertions(+), 11 deletions(-) > > > > diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h > > index a5740fc..978e2f1 100644 > > --- a/include/linux/cpuset.h > > +++ b/include/linux/cpuset.h > > @@ -97,6 +97,8 @@ static inline void set_mems_allowed(nodemask_t nodemask) > > > > #else /* !CONFIG_CPUSETS */ > > > > +#define number_of_cpusets (0) > > + > > static inline int cpuset_init(void) { return 0; } > > static inline void cpuset_init_smp(void) {} > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index c8465d0..3613ba4 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -1137,7 +1137,11 @@ failed: > > #define ALLOC_WMARK_HIGH 0x08 /* use pages_high watermark */ > > #define ALLOC_HARDER 0x10 /* try to alloc harder */ > > #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */ > > +#ifdef CONFIG_CPUSETS > > #define ALLOC_CPUSET 0x40 /* check for correct cpuset */ > > +#else > > +#define ALLOC_CPUSET 0x00 > > +#endif /* CONFIG_CPUSETS */ > > > > #ifdef CONFIG_FAIL_PAGE_ALLOC > > > > @@ -1401,6 +1405,7 @@ get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order, > > nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */ > > int zlc_active = 0; /* set if using zonelist_cache */ > > int did_zlc_setup = 0; /* just call zlc_setup() one time */ > > + int zonelist_filter = 0; > > > > (void)first_zones_zonelist(zonelist, high_zoneidx, nodemask, > > &preferred_zone); > > @@ -1411,6 +1416,10 @@ get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order, > > > > VM_BUG_ON(order >= MAX_ORDER); > > > > + /* Determine in advance if the zonelist needs filtering */ > > + if ((alloc_flags & ALLOC_CPUSET) && unlikely(number_of_cpusets > 1)) > > + zonelist_filter = 1; > > + > > zonelist_scan: > > /* > > * Scan zonelist, looking for a zone with enough free. > > @@ -1418,12 +1427,16 @@ zonelist_scan: > > */ > > for_each_zone_zonelist_nodemask(zone, z, zonelist, > > high_zoneidx, nodemask) { > > - if (NUMA_BUILD && zlc_active && > > - !zlc_zone_worth_trying(zonelist, z, allowednodes)) > > - continue; > > - if ((alloc_flags & ALLOC_CPUSET) && > > - !cpuset_zone_allowed_softwall(zone, gfp_mask)) > > - goto try_next_zone; > > + > > + /* Ignore the additional zonelist filter checks if possible */ > > + if (zonelist_filter) { > > + if (NUMA_BUILD && zlc_active && > > + !zlc_zone_worth_trying(zonelist, z, allowednodes)) > > + continue; > > + if ((alloc_flags & ALLOC_CPUSET) && > > + !cpuset_zone_allowed_softwall(zone, gfp_mask)) > > + goto try_next_zone; > > + } > > if number_of_cpusets==1, old code call zlc_zone_worth_trying(). but your one never call. > it seems regression. > True, but once fixed, the patch becomes a lot less useful. The intention was to avoid the zlc_setup() function which is pretty heavy and hits on HIGHMEM machines quite easily but I did it wrong. I should have made the decision to only call zlc_setup() when there were online NUMA nodes to care about. I'll drop this patch and try again. > > > > > if (!(alloc_flags & ALLOC_NO_WATERMARKS)) { > > unsigned long mark; > > @@ -1445,13 +1458,15 @@ zonelist_scan: > > if (page) > > break; > > this_zone_full: > > - if (NUMA_BUILD) > > + if (NUMA_BUILD && zonelist_filter) > > zlc_mark_zone_full(zonelist, z); > > try_next_zone: > > - if (NUMA_BUILD && !did_zlc_setup) { > > - /* we do zlc_setup after the first zone is tried */ > > - allowednodes = zlc_setup(zonelist, alloc_flags); > > - zlc_active = 1; > > + if (NUMA_BUILD && zonelist_filter) { > > + if (!did_zlc_setup) { > > + /* do zlc_setup after the first zone is tried */ > > + allowednodes = zlc_setup(zonelist, alloc_flags); > > + zlc_active = 1; > > + } > > did_zlc_setup = 1; > > } > > } > > -- > > 1.5.6.5 > > > > -- > > 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 > > > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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