[PATCH 4.4 115/117] zram: try vmalloc() after kmalloc()

Greg Kroah-Hartman
2016-02-14T22:34:16Z

From: Kyeongdon Kim <kyeongdon.kim@lge.com>

commit d913897abace843bba20249f3190167f7895e9c3 upstream.

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.

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:
dump_backtrace+0x0/0x270
show_stack+0x10/0x1c
dump_stack+0x1c/0x28
warn_alloc_failed+0xfc/0x11c
__alloc_pages_nodemask+0x724/0x7f0
__get_free_pages+0x14/0x5c
kmalloc_order_trace+0x38/0xd8
zcomp_lz4_create+0x2c/0x38
zcomp_strm_alloc+0x34/0x78
zcomp_strm_multi_find+0x124/0x1ec
zcomp_strm_find+0xc/0x18
zram_bvec_rw+0x2fc/0x780
zram_make_request+0x25c/0x2d4
generic_make_request+0x80/0xbc
submit_bio+0xa4/0x15c
__swap_writepage+0x218/0x230
swap_writepage+0x3c/0x4c
shrink_page_list+0x51c/0x8d0
shrink_inactive_list+0x3f8/0x60c
shrink_lruvec+0x33c/0x4cc
shrink_zone+0x3c/0x100
try_to_free_pages+0x2b8/0x54c
__alloc_pages_nodemask+0x514/0x7f0
__get_free_pages+0x14/0x5c
proc_info_read+0x50/0xe4
vfs_read+0xa0/0x12c
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>
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/block/zram/zcomp_lz4.c | 23 +++++++++++++++++++++--
drivers/block/zram/zcomp_lzo.c | 23 +++++++++++++++++++++--
2 files changed, 42 insertions(+), 4 deletions(-)

--- 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,
--- 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,