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

[Minchan Kim]

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.senozhat...@gmail.com>

Signed-off-by: Minchan Kim <minc...@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