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authorDan Williams <dan.j.williams@intel.com>2016-01-16 03:55:53 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-16 04:56:32 +0300
commit0e749e54244eec87b2a3cd0a4314e60bc6781115 (patch)
tree4532abd28b323749964a4e5e0a39c1cd37ed2d8a /fs/dax.c
parent52db400fcd50216dd8511a0880b936235755836f (diff)
downloadlinux-0e749e54244eec87b2a3cd0a4314e60bc6781115.tar.xz
dax: increase granularity of dax_clear_blocks() operations
dax_clear_blocks is currently performing a cond_resched() after every PAGE_SIZE memset. We need not check so frequently, for example md-raid only calls cond_resched() at stripe granularity. Also, in preparation for introducing a dax_map_atomic() operation that temporarily pins a dax mapping move the call to cond_resched() to the outer loop. The worst case latency between calls to cond_resched() after this change is 500us the average latency is 133us. This is up from a 10us max and 4us average. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jan Kara <jack@suse.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/dax.c')
-rw-r--r--fs/dax.c22
1 files changed, 8 insertions, 14 deletions
diff --git a/fs/dax.c b/fs/dax.c
index 19492cc65a30..11721c0fc127 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -28,6 +28,7 @@
#include <linux/sched.h>
#include <linux/uio.h>
#include <linux/vmstat.h>
+#include <linux/sizes.h>
/*
* dax_clear_blocks() is called from within transaction context from XFS,
@@ -43,24 +44,17 @@ int dax_clear_blocks(struct inode *inode, sector_t block, long size)
do {
void __pmem *addr;
unsigned long pfn;
- long count;
+ long count, sz;
count = bdev_direct_access(bdev, sector, &addr, &pfn, size);
if (count < 0)
return count;
- BUG_ON(size < count);
- while (count > 0) {
- unsigned pgsz = PAGE_SIZE - offset_in_page(addr);
- if (pgsz > count)
- pgsz = count;
- clear_pmem(addr, pgsz);
- addr += pgsz;
- size -= pgsz;
- count -= pgsz;
- BUG_ON(pgsz & 511);
- sector += pgsz / 512;
- cond_resched();
- }
+ sz = min_t(long, count, SZ_128K);
+ clear_pmem(addr, sz);
+ size -= sz;
+ BUG_ON(sz & 511);
+ sector += sz / 512;
+ cond_resched();
} while (size);
wmb_pmem();