[PATCH] crypto: lzo: try kmalloc() before vmalloc()

From: Eric Dumazet
Date: Tue May 27 2014 - 13:30:25 EST


From: Eric Dumazet <edumazet@xxxxxxxxxx>

zswap allocates one LZO context per online cpu.

Using vmalloc() for small (16KB) memory areas has drawback of slowing
down /proc/vmallocinfo and /proc/meminfo reads, TLB pressure and poor
NUMA locality, as default NUMA policy at boot time is to interleave
pages :

edumazet:~# grep lzo /proc/vmallocinfo | head -4
0xffffc90006062000-0xffffc90006067000 20480 lzo_init+0x1b/0x30 pages=4 vmalloc N0=2 N1=2
0xffffc90006067000-0xffffc9000606c000 20480 lzo_init+0x1b/0x30 pages=4 vmalloc N0=2 N1=2
0xffffc9000606c000-0xffffc90006071000 20480 lzo_init+0x1b/0x30 pages=4 vmalloc N0=2 N1=2
0xffffc90006071000-0xffffc90006076000 20480 lzo_init+0x1b/0x30 pages=4 vmalloc N0=2 N1=2

This patch tries a regular kmalloc() and fallback to vmalloc in case
memory is too fragmented.

Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
---
crypto/lzo.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/crypto/lzo.c b/crypto/lzo.c
index 1c2aa69c54b8..252e791d0ccc 100644
--- a/crypto/lzo.c
+++ b/crypto/lzo.c
@@ -20,6 +20,7 @@
#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/vmalloc.h>
+#include <linux/mm.h>
#include <linux/lzo.h>

struct lzo_ctx {
@@ -30,7 +31,10 @@ static int lzo_init(struct crypto_tfm *tfm)
{
struct lzo_ctx *ctx = crypto_tfm_ctx(tfm);

- ctx->lzo_comp_mem = vmalloc(LZO1X_MEM_COMPRESS);
+ ctx->lzo_comp_mem = kmalloc(LZO1X_MEM_COMPRESS,
+ GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
+ if (!ctx->lzo_comp_mem)
+ ctx->lzo_comp_mem = vmalloc(LZO1X_MEM_COMPRESS);
if (!ctx->lzo_comp_mem)
return -ENOMEM;

@@ -41,7 +45,10 @@ static void lzo_exit(struct crypto_tfm *tfm)
{
struct lzo_ctx *ctx = crypto_tfm_ctx(tfm);

- vfree(ctx->lzo_comp_mem);
+ if (is_vmalloc_addr(ctx->lzo_comp_mem))
+ vfree(ctx->lzo_comp_mem);
+ else
+ kfree(ctx->lzo_comp_mem);
}

static int lzo_compress(struct crypto_tfm *tfm, const u8 *src,


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