Re: [PATCH V3 2/2] zswap: Use movable memory if zpool support allocate movable memory

From: Shakeel Butt
Date: Wed Jul 10 2019 - 14:30:04 EST

Cc: akpm@xxxxxxxxxxxxxxxxxxxx

The email starts at

http://lkml.kernel.org/r/20190605100630.13293-2-teawaterz@xxxxxxxxxxxxxxxxx

On Wed, Jun 5, 2019 at 3:06 AM Hui Zhu <teawaterz@xxxxxxxxxxxxxxxxx> wrote:
>
> This is the third version that was updated according to the comments
> from Sergey Senozhatsky https://lkml.org/lkml/2019/5/29/73 and
> Shakeel Butt https://lkml.org/lkml/2019/6/4/973
>
> zswap compresses swap pages into a dynamically allocated RAM-based
> memory pool. The memory pool should be zbud, z3fold or zsmalloc.
> All of them will allocate unmovable pages. It will increase the
> number of unmovable page blocks that will bad for anti-fragment.
>
> zsmalloc support page migration if request movable page:
> handle = zs_malloc(zram->mem_pool, comp_len,
> GFP_NOIO | __GFP_HIGHMEM |
> __GFP_MOVABLE);
>
> And commit "zpool: Add malloc_support_movable to zpool_driver" add
> zpool_malloc_support_movable check malloc_support_movable to make
> sure if a zpool support allocate movable memory.
>
> This commit let zswap allocate block with gfp
> __GFP_HIGHMEM | __GFP_MOVABLE if zpool support allocate movable memory.
>
> Following part is test log in a pc that has 8G memory and 2G swap.
>
> Without this commit:
> ~# echo lz4 > /sys/module/zswap/parameters/compressor
> ~# echo zsmalloc > /sys/module/zswap/parameters/zpool
> ~# echo 1 > /sys/module/zswap/parameters/enabled
> ~# swapon /swapfile
> ~# cd /home/teawater/kernel/vm-scalability/
> /home/teawater/kernel/vm-scalability# export unit_size=$((9 * 1024 * 1024 * 1024))
> /home/teawater/kernel/vm-scalability# ./case-anon-w-seq
> 2717908992 bytes / 4826062 usecs = 549973 KB/s
> 2717908992 bytes / 4864201 usecs = 545661 KB/s
> 2717908992 bytes / 4867015 usecs = 545346 KB/s
> 2717908992 bytes / 4915485 usecs = 539968 KB/s
> 397853 usecs to free memory
> 357820 usecs to free memory
> 421333 usecs to free memory
> 420454 usecs to free memory
> /home/teawater/kernel/vm-scalability# cat /proc/pagetypeinfo
> Page block order: 9
> Pages per block: 512
>
> Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
> Node 0, zone DMA, type Unmovable 1 1 1 0 2 1 1 0 1 0 0
> Node 0, zone DMA, type Movable 0 0 0 0 0 0 0 0 0 1 3
> Node 0, zone DMA, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA, type CMA 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA, type Isolate 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA32, type Unmovable 6 5 8 6 6 5 4 1 1 1 0
> Node 0, zone DMA32, type Movable 25 20 20 19 22 15 14 11 11 5 767
> Node 0, zone DMA32, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA32, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA32, type CMA 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA32, type Isolate 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone Normal, type Unmovable 4753 5588 5159 4613 3712 2520 1448 594 188 11 0
> Node 0, zone Normal, type Movable 16 3 457 2648 2143 1435 860 459 223 224 296
> Node 0, zone Normal, type Reclaimable 0 0 44 38 11 2 0 0 0 0 0
> Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone Normal, type CMA 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone Normal, type Isolate 0 0 0 0 0 0 0 0 0 0 0
>
> Number of blocks type Unmovable Movable Reclaimable HighAtomic CMA Isolate
> Node 0, zone DMA 1 7 0 0 0 0
> Node 0, zone DMA32 4 1652 0 0 0 0
> Node 0, zone Normal 931 1485 15 0 0 0
>
> With this commit:
> ~# echo lz4 > /sys/module/zswap/parameters/compressor
> ~# echo zsmalloc > /sys/module/zswap/parameters/zpool
> ~# echo 1 > /sys/module/zswap/parameters/enabled
> ~# swapon /swapfile
> ~# cd /home/teawater/kernel/vm-scalability/
> /home/teawater/kernel/vm-scalability# export unit_size=$((9 * 1024 * 1024 * 1024))
> /home/teawater/kernel/vm-scalability# ./case-anon-w-seq
> 2717908992 bytes / 4689240 usecs = 566020 KB/s
> 2717908992 bytes / 4760605 usecs = 557535 KB/s
> 2717908992 bytes / 4803621 usecs = 552543 KB/s
> 2717908992 bytes / 5069828 usecs = 523530 KB/s
> 431546 usecs to free memory
> 383397 usecs to free memory
> 456454 usecs to free memory
> 224487 usecs to free memory
> /home/teawater/kernel/vm-scalability# cat /proc/pagetypeinfo
> Page block order: 9
> Pages per block: 512
>
> Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
> Node 0, zone DMA, type Unmovable 1 1 1 0 2 1 1 0 1 0 0
> Node 0, zone DMA, type Movable 0 0 0 0 0 0 0 0 0 1 3
> Node 0, zone DMA, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA, type CMA 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA, type Isolate 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA32, type Unmovable 10 8 10 9 10 4 3 2 3 0 0
> Node 0, zone DMA32, type Movable 18 12 14 16 16 11 9 5 5 6 775
> Node 0, zone DMA32, type Reclaimable 0 0 0 0 0 0 0 0 0 0 1
> Node 0, zone DMA32, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA32, type CMA 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone DMA32, type Isolate 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone Normal, type Unmovable 2669 1236 452 118 37 14 4 1 2 3 0
> Node 0, zone Normal, type Movable 3850 6086 5274 4327 3510 2494 1520 934 438 220 470
> Node 0, zone Normal, type Reclaimable 56 93 155 124 47 31 17 7 3 0 0
> Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone Normal, type CMA 0 0 0 0 0 0 0 0 0 0 0
> Node 0, zone Normal, type Isolate 0 0 0 0 0 0 0 0 0 0 0
>
> Number of blocks type Unmovable Movable Reclaimable HighAtomic CMA Isolate
> Node 0, zone DMA 1 7 0 0 0 0
> Node 0, zone DMA32 4 1650 2 0 0 0
> Node 0, zone Normal 79 2326 26 0 0 0
>
> You can see that the number of unmovable page blocks is decreased
> when the kernel has this commit.
>
> Signed-off-by: Hui Zhu <teawaterz@xxxxxxxxxxxxxxxxx>
> ---
> mm/zswap.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index a4e4d36ec085..c6bf92bf5890 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -1006,6 +1006,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> char *buf;
> u8 *src, *dst;
> struct zswap_header zhdr = { .swpentry = swp_entry(type, offset) };
> + gfp_t gfp;
>
> /* THP isn't supported */
> if (PageTransHuge(page)) {
> @@ -1079,9 +1080,10 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
>
> /* store */
> hlen = zpool_evictable(entry->pool->zpool) ? sizeof(zhdr) : 0;
> - ret = zpool_malloc(entry->pool->zpool, hlen + dlen,
> - __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM,
> - &handle);
> + gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
> + if (zpool_malloc_support_movable(entry->pool->zpool))
> + gfp |= __GFP_HIGHMEM | __GFP_MOVABLE;
> + ret = zpool_malloc(entry->pool->zpool, hlen + dlen, gfp, &handle);
> if (ret == -ENOSPC) {
> zswap_reject_compress_poor++;
> goto put_dstmem;
> --
> 2.21.0 (Apple Git-120)
>