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Date: Sun, 01 Nov 2015 23:29:53 -0500 From: Dan Williams <dan.j.williams@...el.com> To: axboe@...com Cc: jack@...e.cz, linux-nvdimm@...ts.01.org, david@...morbit.com, linux-kernel@...r.kernel.org, Jeff Moyer <jmoyer@...hat.com>, Jan Kara <jack@...e.com>, ross.zwisler@...ux.intel.com, hch@....de Subject: [PATCH v3 02/15] 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. Reviewed-by: Jan Kara <jack@...e.com> Reviewed-by: Jeff Moyer <jmoyer@...hat.com> Signed-off-by: Dan Williams <dan.j.williams@...el.com> --- fs/dax.c | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 5dc33d788d50..f8e543839e5c 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> int dax_clear_blocks(struct inode *inode, sector_t block, long size) { @@ -38,24 +39,20 @@ 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); + sz = min_t(long, size, SZ_1M); + count = bdev_direct_access(bdev, sector, &addr, &pfn, sz); 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(); - } + if (count < sz) + sz = count; + clear_pmem(addr, sz); + addr += sz; + size -= sz; + BUG_ON(sz & 511); + sector += sz / 512; + cond_resched(); } while (size); wmb_pmem(); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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