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authorAaron Lu <aaron.lu@intel.com>2018-12-28 00:34:39 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 12:11:47 -0800
commit66f71da9dd38af17dc17209cdde7987d4679a699 (patch)
tree8f5614b57e7d7a500023247e34c43899d6337c51 /mm
parent8b09549c2bfd9f3f8f4cdad74107ef4f4ff9cdd7 (diff)
downloadlinux-66f71da9dd38af17dc17209cdde7987d4679a699.tar.bz2
mm/swap: use nr_node_ids for avail_lists in swap_info_struct
Since a2468cc9bfdf ("swap: choose swap device according to numa node"), avail_lists field of swap_info_struct is changed to an array with MAX_NUMNODES elements. This made swap_info_struct size increased to 40KiB and needs an order-4 page to hold it. This is not optimal in that: 1 Most systems have way less than MAX_NUMNODES(1024) nodes so it is a waste of memory; 2 It could cause swapon failure if the swap device is swapped on after system has been running for a while, due to no order-4 page is available as pointed out by Vasily Averin. Solve the above two issues by using nr_node_ids(which is the actual possible node number the running system has) for avail_lists instead of MAX_NUMNODES. nr_node_ids is unknown at compile time so can't be directly used when declaring this array. What I did here is to declare avail_lists as zero element array and allocate space for it when allocating space for swap_info_struct. The reason why keep using array but not pointer is plist_for_each_entry needs the field to be part of the struct, so pointer will not work. This patch is on top of Vasily Averin's fix commit. I think the use of kvzalloc for swap_info_struct is still needed in case nr_node_ids is really big on some systems. Link: http://lkml.kernel.org/r/20181115083847.GA11129@intel.com Signed-off-by: Aaron Lu <aaron.lu@intel.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vasily Averin <vvs@virtuozzo.com> Cc: Huang Ying <ying.huang@intel.com> 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/swapfile.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 8688ae65ef58..6e06821623f6 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2812,8 +2812,9 @@ static struct swap_info_struct *alloc_swap_info(void)
struct swap_info_struct *p;
unsigned int type;
int i;
+ int size = sizeof(*p) + nr_node_ids * sizeof(struct plist_node);
- p = kvzalloc(sizeof(*p), GFP_KERNEL);
+ p = kvzalloc(size, GFP_KERNEL);
if (!p)
return ERR_PTR(-ENOMEM);