[PATCH v5 12/12] zram: use __GFP_MOVABLE for memory allocation

Minchan Kim
2016-05-09T02:20:33Z

Zsmalloc is ready for page migration so zram can use __GFP_MOVABLE
from now on.

I did test to see how it helps to make higher order pages.
Test scenario is as follows.

KVM guest, 1G memory, ext4 formated zram block device,

for i in `seq 1 8`;
do
dd if=/dev/vda1 of=mnt/test$i.txt bs=128M count=1 &
done

wait `pidof dd`

for i in `seq 1 2 8`;
do
rm -rf mnt/test$i.txt
done
fstrim -v mnt

echo "init"
cat /proc/buddyinfo

echo "compaction"
echo 1 > /proc/sys/vm/compact_memory
cat /proc/buddyinfo

old:

init
Node 0, zone DMA 208 120 51 41 11 0 0 0 0 0 0
Node 0, zone DMA32 16380 13777 9184 3805 789 54 3 0 0 0 0
compaction
Node 0, zone DMA 132 82 40 39 16 2 1 0 0 0 0
Node 0, zone DMA32 5219 5526 4969 3455 1831 677 139 15 0 0 0

new:

init
Node 0, zone DMA 379 115 97 19 2 0 0 0 0 0 0
Node 0, zone DMA32 18891 16774 10862 3947 637 21 0 0 0 0 0
compaction 1
Node 0, zone DMA 214 66 87 29 10 3 0 0 0 0 0
Node 0, zone DMA32 1612 3139 3154 2469 1745 990 384 94 7 0 0

As you can see, compaction made so many high-order pages. Yay!

Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
drivers/block/zram/zram_drv.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 8fcfbebe79cd..55419f104f67 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -714,13 +714,15 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
handle = zs_malloc(meta->mem_pool, clen,
__GFP_KSWAPD_RECLAIM |
__GFP_NOWARN |
- __GFP_HIGHMEM);
+ __GFP_HIGHMEM |
+ __GFP_MOVABLE);
if (!handle) {
zcomp_strm_release(zram->comp, zstrm);
zstrm = NULL;

handle = zs_malloc(meta->mem_pool, clen,
- GFP_NOIO | __GFP_HIGHMEM);
+ GFP_NOIO | __GFP_HIGHMEM |
+ __GFP_MOVABLE);
if (handle)
goto compress_again;

--
1.9.1