[v3,5/7] zram: Convert to using memset_l
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Message ID 20170324161318.18718-6-willy@infradead.org
State New, archived
Headers show

Commit Message

Matthew Wilcox March 24, 2017, 4:13 p.m. UTC
From: Matthew Wilcox <mawilcox@microsoft.com>

zram was the motivation for creating memset_l().  Minchan Kim sees a 7%
performance improvement on x86 with 100MB of non-zero deduplicatable
data:

        perf stat -r 10 dd if=/dev/zram0 of=/dev/null

vanilla:        0.232050465 seconds time elapsed ( +-  0.51% )
memset_l:	0.217219387 seconds time elapsed ( +-  0.07% )

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Minchan Kim <minchan@kernel.org>
---
 drivers/block/zram/zram_drv.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

Comments

Minchan Kim March 27, 2017, 5:01 a.m. UTC | #1
On Fri, Mar 24, 2017 at 09:13:16AM -0700, Matthew Wilcox wrote:
> From: Matthew Wilcox <mawilcox@microsoft.com>
> 
> zram was the motivation for creating memset_l().  Minchan Kim sees a 7%
> performance improvement on x86 with 100MB of non-zero deduplicatable
> data:
> 
>         perf stat -r 10 dd if=/dev/zram0 of=/dev/null
> 
> vanilla:        0.232050465 seconds time elapsed ( +-  0.51% )
> memset_l:	0.217219387 seconds time elapsed ( +-  0.07% )
> 
> Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
> Tested-by: Minchan Kim <minchan@kernel.org>
Acked-by: Minchan Kim <minchan@kernel.org>

Thanks!

Patch
diff mbox

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index e27d89a36c34..25dcad309695 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -157,20 +157,11 @@  static inline void update_used_max(struct zram *zram,
 	} while (old_max != cur_max);
 }
 
-static inline void zram_fill_page(char *ptr, unsigned long len,
+static inline void zram_fill_page(void *ptr, unsigned long len,
 					unsigned long value)
 {
-	int i;
-	unsigned long *page = (unsigned long *)ptr;
-
 	WARN_ON_ONCE(!IS_ALIGNED(len, sizeof(unsigned long)));
-
-	if (likely(value == 0)) {
-		memset(ptr, 0, len);
-	} else {
-		for (i = 0; i < len / sizeof(*page); i++)
-			page[i] = value;
-	}
+	memset_l(ptr, value, len / sizeof(unsigned long));
 }
 
 static bool page_same_filled(void *ptr, unsigned long *element)
@@ -193,7 +184,7 @@  static bool page_same_filled(void *ptr, unsigned long *element)
 static void handle_same_page(struct bio_vec *bvec, unsigned long element)
 {
 	struct page *page = bvec->bv_page;
-	void *user_mem;
+	char *user_mem;
 
 	user_mem = kmap_atomic(page);
 	zram_fill_page(user_mem + bvec->bv_offset, bvec->bv_len, element);