diff options
author | Dan Williams <dan.j.williams@intel.com> | 2016-01-16 00:55:53 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-16 01:56:32 (GMT) |
commit | 0e749e54244eec87b2a3cd0a4314e60bc6781115 (patch) | |
tree | 4532abd28b323749964a4e5e0a39c1cd37ed2d8a | |
parent | 52db400fcd50216dd8511a0880b936235755836f (diff) | |
download | linux-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>
-rw-r--r-- | fs/dax.c | 22 |
1 files changed, 8 insertions, 14 deletions
@@ -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(); |