Currently newly allocated swap_info_struct can be quickly freed.
This patch avoid uneccessary high-order page allocation and helps
to decrease the memory pressure.
Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
---
mm/swapfile.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 8688ae65ef58..53ec2f0cdf26 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2809,14 +2809,17 @@ late_initcall(max_swapfiles_check);
static struct swap_info_struct *alloc_swap_info(void)
{
- struct swap_info_struct *p;
+ struct swap_info_struct *p = NULL;
unsigned int type;
int i;
+ bool force_alloc = false;
- p = kvzalloc(sizeof(*p), GFP_KERNEL);
- if (!p)
- return ERR_PTR(-ENOMEM);
-
+retry:
+ if (force_alloc) {
+ p = kvzalloc(sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return ERR_PTR(-ENOMEM);
+ }
spin_lock(&swap_lock);
for (type = 0; type < nr_swapfiles; type++) {
if (!(swap_info[type]->flags & SWP_USED))
@@ -2828,6 +2831,11 @@ static struct swap_info_struct *alloc_swap_info(void)
return ERR_PTR(-EPERM);
}
if (type >= nr_swapfiles) {
+ if (!force_alloc) {
+ force_alloc = true;
+ spin_unlock(&swap_lock);
+ goto retry;
+ }
p->type = type;
swap_info[type] = p;
/*
--
2.17.1
