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Subject: Re: Re: [PATCH v4 2/2] zram: try vmalloc() after kmalloc()
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
References: <1448973390-21170-1-git-send-email-sergey.senozhatsky@gmail.com>
 <20151218002829.GA4809@swordfish>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Minchan Kim <minchan@kernel.org>, linux-kernel@vger.kernel.org
From: Kyeongdon Kim <kyeongdon.kim@lge.com>
Message-ID: <5678BF21.9010504@lge.com>
Date: Tue, 22 Dec 2015 12:10:25 +0900
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On 2015-12-18 오전 9:28, Sergey Senozhatsky wrote:
> On (12/01/15 21:36), Sergey Senozhatsky wrote:
>> When we're using LZ4 multi compression streams for zram swap, we found
> out
>> page allocation failure message in system running test. That was not only
>> once, but a few(2 - 5 times per test). Also, some failure cases were
>> continually occurring to try allocation order 3.
>>
>> In order to make parallel compression private data, we should call
>> kzalloc() with order 2/3 in runtime(lzo/lz4). But if there is no order
>> 2/3 size memory to allocate in that time, page allocation fails. This
>> patch makes to use vmalloc() as fallback of kmalloc(), this prevents page
>> alloc failure warning.
>>
>> After using this, we never found warning message in running test, also It
>> could reduce process startup latency about 60-120ms in each case.
>>
> 
> Hello Kyeongdon,
> 
> just to make sure, the patch works fine for you and we can move
> forward and Cc -stable. correct?
> 
> -ss
> 
Hello Sergey,

I was on vacation so I checked your email a moment ago, sorry about it.
We're using this patch set. and we couldn't find any issue from this one
until now.

Thanks,
Kyeongdon Kim

>> For reference a call trace :
>>
>> Binder_1: page allocation failure: order:3, mode:0x10c0d0
>> CPU: 0 PID: 424 Comm: Binder_1 Tainted: GW 3.10.49-perf-g991d02b-dirty
> #20
>> Call trace:
>> [<ffffffc0002069c8>] dump_backtrace+0x0/0x270
>> [<ffffffc000206c48>] show_stack+0x10/0x1c
>> [<ffffffc000cb51c8>] dump_stack+0x1c/0x28
>> [<ffffffc0002bbfc8>] warn_alloc_failed+0xfc/0x11c
>> [<ffffffc0002bf518>] __alloc_pages_nodemask+0x724/0x7f0
>> [<ffffffc0002bf5f8>] __get_free_pages+0x14/0x5c
>> [<ffffffc0002ed6a4>] kmalloc_order_trace+0x38/0xd8
>> [<ffffffc0005d9738>] zcomp_lz4_create+0x2c/0x38
>> [<ffffffc0005d78f0>] zcomp_strm_alloc+0x34/0x78
>> [<ffffffc0005d7a58>] zcomp_strm_multi_find+0x124/0x1ec
>> [<ffffffc0005d7c14>] zcomp_strm_find+0xc/0x18
>> [<ffffffc0005d8fa0>] zram_bvec_rw+0x2fc/0x780
>> [<ffffffc0005d9680>] zram_make_request+0x25c/0x2d4
>> [<ffffffc00040f8ac>] generic_make_request+0x80/0xbc
>> [<ffffffc00040f98c>] submit_bio+0xa4/0x15c
>> [<ffffffc0002e8bb0>] __swap_writepage+0x218/0x230
>> [<ffffffc0002e8c04>] swap_writepage+0x3c/0x4c
>> [<ffffffc0002c7384>] shrink_page_list+0x51c/0x8d0
>> [<ffffffc0002c7e88>] shrink_inactive_list+0x3f8/0x60c
>> [<ffffffc0002c86c8>] shrink_lruvec+0x33c/0x4cc
>> [<ffffffc0002c8894>] shrink_zone+0x3c/0x100
>> [<ffffffc0002c8c10>] try_to_free_pages+0x2b8/0x54c
>> [<ffffffc0002bf308>] __alloc_pages_nodemask+0x514/0x7f0
>> [<ffffffc0002bf5f8>] __get_free_pages+0x14/0x5c
>> [<ffffffc0003446cc>] proc_info_read+0x50/0xe4
>> [<ffffffc0002f5204>] vfs_read+0xa0/0x12c
>> [<ffffffc0002f59c8>] SyS_read+0x44/0x74
>> DMA: 3397*4kB (MC) 26*8kB (RC) 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB
>> 0*512kB 0*1024kB 0*2048kB 0*4096kB = 13796kB
>>
>> [minchan@kernel.org: change vmalloc gfp and adding comment about gfp]
>> [sergey.senozhatsky@gmail.com: tweak comments and styles]
>> Signed-off-by: Kyeongdon Kim <kyeongdon.kim@lge.com>
>> Signed-off-by: Minchan Kim <minchan@kernel.org>
>> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
>> ---
>> drivers/block/zram/zcomp_lz4.c | 23 +++++++++++++++++++++--
>> drivers/block/zram/zcomp_lzo.c | 23 +++++++++++++++++++++--
>> 2 files changed, 42 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/block/zram/zcomp_lz4.c
> b/drivers/block/zram/zcomp_lz4.c
>> index ee44b51..dd60831 100644
>> --- a/drivers/block/zram/zcomp_lz4.c
>> +++ b/drivers/block/zram/zcomp_lz4.c
>> @@ -10,17 +10,36 @@
>> #include <linux/kernel.h>
>> #include <linux/slab.h>
>> #include <linux/lz4.h>
>> +#include <linux/vmalloc.h>
>> +#include <linux/mm.h>
>>
>> #include "zcomp_lz4.h"
>>
>> static void *zcomp_lz4_create(void)
>> {
>> - return kzalloc(LZ4_MEM_COMPRESS, GFP_NOIO);
>> + void *ret;
>> +
>> + /*
>> + * This function can be called in swapout/fs write path
>> + * so we can't use GFP_FS|IO. And it assumes we already
>> + * have at least one stream in zram initialization so we
>> + * don't do best effort to allocate more stream in here.
>> + * A default stream will work well without further multiple
>> + * streams. That's why we use NORETRY | NOWARN.
>> + */
>> + ret = kzalloc(LZ4_MEM_COMPRESS, GFP_NOIO | __GFP_NORETRY |
>> + __GFP_NOWARN);
>> + if (!ret)
>> + ret = __vmalloc(LZ4_MEM_COMPRESS,
>> + GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN |
>> + __GFP_ZERO | __GFP_HIGHMEM,
>> + PAGE_KERNEL);
>> + return ret;
>> }
>>
>> static void zcomp_lz4_destroy(void *private)
>> {
>> - kfree(private);
>> + kvfree(private);
>> }
>>
>> static int zcomp_lz4_compress(const unsigned char *src, unsigned char
> *dst,
>> diff --git a/drivers/block/zram/zcomp_lzo.c
> b/drivers/block/zram/zcomp_lzo.c
>> index 683ce04..edc5499 100644
>> --- a/drivers/block/zram/zcomp_lzo.c
>> +++ b/drivers/block/zram/zcomp_lzo.c
>> @@ -10,17 +10,36 @@
>> #include <linux/kernel.h>
>> #include <linux/slab.h>
>> #include <linux/lzo.h>
>> +#include <linux/vmalloc.h>
>> +#include <linux/mm.h>
>>
>> #include "zcomp_lzo.h"
>>
>> static void *lzo_create(void)
>> {
>> - return kzalloc(LZO1X_MEM_COMPRESS, GFP_NOIO);
>> + void *ret;
>> +
>> + /*
>> + * This function can be called in swapout/fs write path
>> + * so we can't use GFP_FS|IO. And it assumes we already
>> + * have at least one stream in zram initialization so we
>> + * don't do best effort to allocate more stream in here.
>> + * A default stream will work well without further multiple
>> + * streams. That's why we use NORETRY | NOWARN.
>> + */
>> + ret = kzalloc(LZO1X_MEM_COMPRESS, GFP_NOIO | __GFP_NORETRY |
>> + __GFP_NOWARN);
>> + if (!ret)
>> + ret = __vmalloc(LZO1X_MEM_COMPRESS,
>> + GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN |
>> + __GFP_ZERO | __GFP_HIGHMEM,
>> + PAGE_KERNEL);
>> + return ret;
>> }
>>
>> static void lzo_destroy(void *private)
>> {
>> - kfree(private);
>> + kvfree(private);
>> }
>>
>> static int lzo_compress(const unsigned char *src, unsigned char *dst,
>> --
>> 2.6.2
>>