From 3148890bfa4f36c9949871264e06ef4d449eeff9 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Mon, 28 Nov 2005 13:44:03 -0800 Subject: [PATCH] mm: __alloc_pages cleanup fix I believe this patch is required to fix breakage in the asynch reclaim watermark logic introduced by this patch: http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=7fb1d9fca5c6e3b06773b69165a73f3fb786b8ee Just some background of the watermark logic in case it isn't clear... Basically what we have is this: --- pages_high | | (a) | --- pages_low | | (b) | --- pages_min | | (c) | --- 0 Now when pages_low is reached, we want to kick asynch reclaim, which gives us an interval of "b" before we must start synch reclaim, and gives kswapd an interval of "a" before it need go back to sleep. When pages_min is reached, normal allocators must enter synch reclaim, but PF_MEMALLOC, ALLOC_HARDER, and ALLOC_HIGH (ie. atomic allocations, recursive allocations, etc.) get access to varying amounts of the reserve "c". Signed-off-by: Nick Piggin Cc: "Seth, Rohit" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) (limited to 'mm') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 1731236dec35..b257720edfc8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -773,9 +773,12 @@ again: } #define ALLOC_NO_WATERMARKS 0x01 /* don't check watermarks at all */ -#define ALLOC_HARDER 0x02 /* try to alloc harder */ -#define ALLOC_HIGH 0x04 /* __GFP_HIGH set */ -#define ALLOC_CPUSET 0x08 /* check for correct cpuset */ +#define ALLOC_WMARK_MIN 0x02 /* use pages_min watermark */ +#define ALLOC_WMARK_LOW 0x04 /* use pages_low watermark */ +#define ALLOC_WMARK_HIGH 0x08 /* use pages_high watermark */ +#define ALLOC_HARDER 0x10 /* try to alloc harder */ +#define ALLOC_HIGH 0x20 /* __GFP_HIGH set */ +#define ALLOC_CPUSET 0x40 /* check for correct cpuset */ /* * Return 1 if free pages are above 'mark'. This takes into account the order @@ -830,7 +833,14 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, continue; if (!(alloc_flags & ALLOC_NO_WATERMARKS)) { - if (!zone_watermark_ok(*z, order, (*z)->pages_low, + unsigned long mark; + if (alloc_flags & ALLOC_WMARK_MIN) + mark = (*z)->pages_min; + else if (alloc_flags & ALLOC_WMARK_LOW) + mark = (*z)->pages_low; + else + mark = (*z)->pages_high; + if (!zone_watermark_ok(*z, order, mark, classzone_idx, alloc_flags)) continue; } @@ -871,7 +881,7 @@ restart: } page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order, - zonelist, ALLOC_CPUSET); + zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET); if (page) goto got_pg; @@ -888,7 +898,7 @@ restart: * cannot run direct reclaim, or if the caller has realtime scheduling * policy. */ - alloc_flags = 0; + alloc_flags = ALLOC_WMARK_MIN; if ((unlikely(rt_task(p)) && !in_interrupt()) || !wait) alloc_flags |= ALLOC_HARDER; if (gfp_mask & __GFP_HIGH) @@ -959,7 +969,7 @@ rebalance: * under heavy pressure. */ page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order, - zonelist, ALLOC_CPUSET); + zonelist, ALLOC_WMARK_HIGH|ALLOC_CPUSET); if (page) goto got_pg; -- cgit v1.2.3-58-ga151