From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <417F5604.3000908@yahoo.com.au> Date: Wed, 27 Oct 2004 18:02:12 +1000 From: Nick Piggin MIME-Version: 1.0 Subject: [PATCH 2/3] higher order watermarks References: <417F5584.2070400@yahoo.com.au> <417F55B9.7090306@yahoo.com.au> In-Reply-To: <417F55B9.7090306@yahoo.com.au> Content-Type: multipart/mixed; boundary="------------010402030903050409000306" Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Linux Memory Management , Linus Torvalds List-ID: This is a multi-part message in MIME format. --------------010402030903050409000306 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit 2/3 --------------010402030903050409000306 Content-Type: text/x-patch; name="vm-alloc-order-watermarks.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="vm-alloc-order-watermarks.patch" Move the watermark checking code into a single function. Extend it to account for the order of the allocation and the number of free pages that could satisfy such a request. Signed-off-by: Nick Piggin --- linux-2.6-npiggin/include/linux/mmzone.h | 2 + linux-2.6-npiggin/mm/page_alloc.c | 58 ++++++++++++++++++++----------- 2 files changed, 41 insertions(+), 19 deletions(-) diff -puN mm/page_alloc.c~vm-alloc-order-watermarks mm/page_alloc.c --- linux-2.6/mm/page_alloc.c~vm-alloc-order-watermarks 2004-10-27 16:41:32.000000000 +1000 +++ linux-2.6-npiggin/mm/page_alloc.c 2004-10-27 17:53:33.000000000 +1000 @@ -586,6 +586,37 @@ buffered_rmqueue(struct zone *zone, int } /* + * Return 1 if free pages are above 'mark'. This takes into account the order + * of the allocation. + */ +int zone_watermark_ok(struct zone *z, int order, unsigned long mark, + int alloc_type, int can_try_harder, int gfp_high) +{ + /* free_pages my go negative - that's OK */ + long min = mark, free_pages = z->free_pages - (1 << order) + 1; + int o; + + if (gfp_high) + min -= min / 2; + if (can_try_harder) + min -= min / 4; + + if (free_pages <= min + z->protection[alloc_type]) + return 0; + for (o = 0; o < order; o++) { + /* At the next order, this order's pages become unavailable */ + free_pages -= z->free_area[order].nr_free << o; + + /* Require fewer higher order pages to be free */ + min >>= 1; + + if (free_pages <= min) + return 0; + } + return 1; +} + +/* * This is the 'heart' of the zoned buddy allocator. * * Herein lies the mysterious "incremental min". That's the @@ -606,7 +637,6 @@ __alloc_pages(unsigned int gfp_mask, uns struct zonelist *zonelist) { const int wait = gfp_mask & __GFP_WAIT; - unsigned long min; struct zone **zones, *z; struct page *page; struct reclaim_state reclaim_state; @@ -636,9 +666,9 @@ __alloc_pages(unsigned int gfp_mask, uns /* Go through the zonelist once, looking for a zone with enough free */ for (i = 0; (z = zones[i]) != NULL; i++) { - min = z->pages_low + (1<protection[alloc_type]; - if (z->free_pages < min) + if (!zone_watermark_ok(z, order, z->pages_low, + alloc_type, 0, 0)) continue; page = buffered_rmqueue(z, order, gfp_mask); @@ -654,14 +684,9 @@ __alloc_pages(unsigned int gfp_mask, uns * coming from realtime tasks to go deeper into reserves */ for (i = 0; (z = zones[i]) != NULL; i++) { - min = z->pages_min; - if (gfp_mask & __GFP_HIGH) - min /= 2; - if (can_try_harder) - min -= min / 4; - min += (1<protection[alloc_type]; - - if (z->free_pages < min) + if (!zone_watermark_ok(z, order, z->pages_min, + alloc_type, can_try_harder, + gfp_mask & __GFP_HIGH)) continue; page = buffered_rmqueue(z, order, gfp_mask); @@ -697,14 +722,9 @@ rebalance: /* go through the zonelist yet one more time */ for (i = 0; (z = zones[i]) != NULL; i++) { - min = z->pages_min; - if (gfp_mask & __GFP_HIGH) - min /= 2; - if (can_try_harder) - min -= min / 4; - min += (1<protection[alloc_type]; - - if (z->free_pages < min) + if (!zone_watermark_ok(z, order, z->pages_min, + alloc_type, can_try_harder, + gfp_mask & __GFP_HIGH)) continue; page = buffered_rmqueue(z, order, gfp_mask); diff -puN include/linux/mmzone.h~vm-alloc-order-watermarks include/linux/mmzone.h --- linux-2.6/include/linux/mmzone.h~vm-alloc-order-watermarks 2004-10-27 16:41:32.000000000 +1000 +++ linux-2.6-npiggin/include/linux/mmzone.h 2004-10-27 17:52:07.000000000 +1000 @@ -279,6 +279,8 @@ void get_zone_counts(unsigned long *acti unsigned long *free); void build_all_zonelists(void); void wakeup_kswapd(struct zone *zone); +int zone_watermark_ok(struct zone *z, int order, unsigned long mark, + int alloc_type, int can_try_harder, int gfp_high); /* * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc. _ --------------010402030903050409000306-- -- 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: aart@kvack.org