Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755452Ab0K3KQk (ORCPT ); Tue, 30 Nov 2010 05:16:40 -0500 Received: from e28smtp06.in.ibm.com ([122.248.162.6]:53345 "EHLO e28smtp06.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754236Ab0K3KQi (ORCPT ); Tue, 30 Nov 2010 05:16:38 -0500 Subject: [PATCH 3/3] Provide control over unmapped pages To: linux-mm@kvack.org, Christoph Lameter From: Balbir Singh Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, kvm Date: Tue, 30 Nov 2010 15:46:31 +0530 Message-ID: <20101130101602.17475.32611.stgit@localhost6.localdomain6> In-Reply-To: <20101130101126.17475.18729.stgit@localhost6.localdomain6> References: <20101130101126.17475.18729.stgit@localhost6.localdomain6> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5555 Lines: 174 Provide control using zone_reclaim() and a boot parameter. The code reuses functionality from zone_reclaim() to isolate unmapped pages and reclaim them as a priority, ahead of other mapped pages. Signed-off-by: Balbir Singh --- include/linux/swap.h | 5 ++- mm/page_alloc.c | 7 +++-- mm/vmscan.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 79 insertions(+), 5 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index eba53e7..78b0830 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -252,11 +252,12 @@ extern int vm_swappiness; extern int remove_mapping(struct address_space *mapping, struct page *page); extern long vm_total_pages; -#ifdef CONFIG_NUMA -extern int zone_reclaim_mode; extern int sysctl_min_unmapped_ratio; extern int sysctl_min_slab_ratio; extern int zone_reclaim(struct zone *, gfp_t, unsigned int); +extern bool should_balance_unmapped_pages(struct zone *zone); +#ifdef CONFIG_NUMA +extern int zone_reclaim_mode; #else #define zone_reclaim_mode 0 static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 62b7280..4228da3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1662,6 +1662,9 @@ zonelist_scan: unsigned long mark; int ret; + if (should_balance_unmapped_pages(zone)) + wakeup_kswapd(zone, order); + mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK]; if (zone_watermark_ok(zone, order, mark, classzone_idx, alloc_flags)) @@ -4136,10 +4139,10 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat, zone->spanned_pages = size; zone->present_pages = realsize; -#ifdef CONFIG_NUMA - zone->node = nid; zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio) / 100; +#ifdef CONFIG_NUMA + zone->node = nid; zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100; #endif zone->name = zone_names[j]; diff --git a/mm/vmscan.c b/mm/vmscan.c index 0ac444f..98950f4 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -145,6 +145,21 @@ static DECLARE_RWSEM(shrinker_rwsem); #define scanning_global_lru(sc) (1) #endif +static unsigned long balance_unmapped_pages(int priority, struct zone *zone, + struct scan_control *sc); +static int unmapped_page_control __read_mostly; + +static int __init unmapped_page_control_parm(char *str) +{ + unmapped_page_control = 1; + /* + * XXX: Should we tweak swappiness here? + */ + return 1; +} +__setup("unmapped_page_control", unmapped_page_control_parm); + + static struct zone_reclaim_stat *get_reclaim_stat(struct zone *zone, struct scan_control *sc) { @@ -2223,6 +2238,12 @@ loop_again: shrink_active_list(SWAP_CLUSTER_MAX, zone, &sc, priority, 0); + /* + * We do unmapped page balancing once here and once + * below, so that we don't lose out + */ + balance_unmapped_pages(priority, zone, &sc); + if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone), 0, 0)) { end_zone = i; @@ -2258,6 +2279,11 @@ loop_again: continue; sc.nr_scanned = 0; + /* + * Balance unmapped pages upfront, this should be + * really cheap + */ + balance_unmapped_pages(priority, zone, &sc); /* * Call soft limit reclaim before calling shrink_zone. @@ -2491,7 +2517,8 @@ void wakeup_kswapd(struct zone *zone, int order) pgdat->kswapd_max_order = order; if (!waitqueue_active(&pgdat->kswapd_wait)) return; - if (zone_watermark_ok_safe(zone, order, low_wmark_pages(zone), 0, 0)) + if (zone_watermark_ok_safe(zone, order, low_wmark_pages(zone), 0, 0) && + !should_balance_unmapped_pages(zone)) return; trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order); @@ -2740,6 +2767,49 @@ zone_reclaim_unmapped_pages(struct zone *zone, struct scan_control *sc, } /* + * Routine to balance unmapped pages, inspired from the code under + * CONFIG_NUMA that does unmapped page and slab page control by keeping + * min_unmapped_pages in the zone. We currently reclaim just unmapped + * pages, slab control will come in soon, at which point this routine + * should be called balance cached pages + */ +static unsigned long balance_unmapped_pages(int priority, struct zone *zone, + struct scan_control *sc) +{ + if (unmapped_page_control && + (zone_unmapped_file_pages(zone) > zone->min_unmapped_pages)) { + struct scan_control nsc; + unsigned long nr_pages; + + nsc = *sc; + + nsc.swappiness = 0; + nsc.may_writepage = 0; + nsc.may_unmap = 0; + nsc.nr_reclaimed = 0; + + nr_pages = zone_unmapped_file_pages(zone) - + zone->min_unmapped_pages; + /* Magically try to reclaim eighth the unmapped cache pages */ + nr_pages >>= 3; + + zone_reclaim_unmapped_pages(zone, &nsc, nr_pages); + return nsc.nr_reclaimed; + } + return 0; +} + +#define UNMAPPED_PAGE_RATIO 16 +bool should_balance_unmapped_pages(struct zone *zone) +{ + if (unmapped_page_control && + (zone_unmapped_file_pages(zone) > + UNMAPPED_PAGE_RATIO * zone->min_unmapped_pages)) + return true; + return false; +} + +/* * Try to free up some pages from this zone through reclaim. */ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) -- 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/