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authorMinchan Kim <minchan@kernel.org>2016-07-28 15:47:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-28 16:07:41 -0700
commit9cb937e2195bc46aa3f21c50f78ee994bbf6e04a (patch)
tree2803019792d87c99a1ef2b0f3ea81f626d9e85c1 /mm
parentbca6759258dbef378bcf5b872177bcd2259ceb68 (diff)
downloadlinux-9cb937e2195bc46aa3f21c50f78ee994bbf6e04a.tar.bz2
mm, page_alloc: fix dirtyable highmem calculation
When I tested vmscale in mmtest in 32bit, I found the benchmark was slow down 0.5 times. base node 1 global-1 User 12.98 16.04 System 147.61 166.42 Elapsed 26.48 38.08 With vmstat, I found IO wait avg is much increased compared to base. The reason was highmem_dirtyable_memory accumulates free pages and highmem_file_pages from HIGHMEM to MOVABLE zones which was wrong. With that, dirth_thresh in throtlle_vm_write is always 0 so that it calls congestion_wait frequently if writeback starts. With this patch, it is much recovered. base node fi 1 global-1 fix User 12.98 16.04 13.78 System 147.61 166.42 143.92 Elapsed 26.48 38.08 29.64 Link: http://lkml.kernel.org/r/1468404004-5085-4-git-send-email-mgorman@techsingularity.net Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page-writeback.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0bca2376bd42..573d138fa7a5 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -307,27 +307,31 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
{
#ifdef CONFIG_HIGHMEM
int node;
- unsigned long x = 0;
+ unsigned long x;
int i;
- unsigned long dirtyable = atomic_read(&highmem_file_pages);
+ unsigned long dirtyable = 0;
for_each_node_state(node, N_HIGH_MEMORY) {
for (i = ZONE_NORMAL + 1; i < MAX_NR_ZONES; i++) {
struct zone *z;
+ unsigned long nr_pages;
if (!is_highmem_idx(i))
continue;
z = &NODE_DATA(node)->node_zones[i];
- dirtyable += zone_page_state(z, NR_FREE_PAGES);
+ if (!populated_zone(z))
+ continue;
+ nr_pages = zone_page_state(z, NR_FREE_PAGES);
/* watch for underflows */
- dirtyable -= min(dirtyable, high_wmark_pages(z));
-
- x += dirtyable;
+ nr_pages -= min(nr_pages, high_wmark_pages(z));
+ dirtyable += nr_pages;
}
}
+ x = dirtyable + atomic_read(&highmem_file_pages);
+
/*
* Unreclaimable memory (kernel memory or anonymous memory
* without swap) can bring down the dirtyable pages below