From 013110a73dcf970cb28c5b0a79f9eee577ea6aa2 Mon Sep 17 00:00:00 2001 From: Yaowei Bai Date: Tue, 8 Sep 2015 15:04:10 -0700 Subject: [PATCH] mm/page_alloc.c: fix a misleading comment The comment says that the per-cpu batchsize and zone watermarks are determined by present_pages which is definitely wrong, they are both calculated from managed_pages. Fix it. Signed-off-by: Yaowei Bai Acked-by: Michal Hocko Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/sysctl/vm.txt | 4 ++-- mm/page_alloc.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 9c3f2f8054b5..a4482fceacec 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -349,7 +349,7 @@ zone[i]'s protection[j] is calculated by following expression. (i < j): zone[i]->protection[j] - = (total sums of present_pages from zone[i+1] to zone[j] on the node) + = (total sums of managed_pages from zone[i+1] to zone[j] on the node) / lowmem_reserve_ratio[i]; (i = j): (should not be protected. = 0; @@ -360,7 +360,7 @@ The default values of lowmem_reserve_ratio[i] are 256 (if zone[i] means DMA or DMA32 zone) 32 (others). As above expression, they are reciprocal number of ratio. -256 means 1/256. # of protection pages becomes about "0.39%" of total present +256 means 1/256. # of protection pages becomes about "0.39%" of total managed pages of higher zones on the node. If you would like to protect more pages, smaller values are effective. diff --git a/mm/page_alloc.c b/mm/page_alloc.c index bdaa0cf8fd41..59abb47b70ee 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6022,7 +6022,7 @@ void __init mem_init_print_info(const char *str) * set_dma_reserve - set the specified number of pages reserved in the first zone * @new_dma_reserve: The number of pages to mark reserved * - * The per-cpu batchsize and zone watermarks are determined by present_pages. + * The per-cpu batchsize and zone watermarks are determined by managed_pages. * In the DMA zone, a significant percentage may be consumed by kernel image * and other unfreeable allocations which can skew the watermarks badly. This * function may optionally be used to account for unfreeable pages in the -- 2.20.1