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authorMikulas Patocka <mpatocka@redhat.com>2020-02-24 10:20:34 +0100
committerMike Snitzer <snitzer@redhat.com>2020-03-24 11:55:09 -0400
commitdc8a01ae1dbd7bac98368da4d8f81632512429f5 (patch)
treeb95398da45d5805185902d67c7baa837c0328b7a
parent3923d4854e189d84c6ec22e66d536d3498f2747c (diff)
dm writecache: optimize superblock write
If we write a superblock in writecache_flush, we don't need to set bit and scan the bitmap for it - we can just write the superblock directly. Also, we can set the flag REQ_FUA on the write bio, so that we don't need to submit a flush bio afterwards. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
-rw-r--r--drivers/md/dm-writecache.c34
1 files changed, 32 insertions, 2 deletions
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index e5c7b9072dd0..e274e5a4d425 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -509,6 +509,34 @@ static void ssd_commit_flushed(struct dm_writecache *wc, bool wait_for_ios)
memset(wc->dirty_bitmap, 0, wc->dirty_bitmap_size);
}
+static void ssd_commit_superblock(struct dm_writecache *wc)
+{
+ int r;
+ struct dm_io_region region;
+ struct dm_io_request req;
+
+ region.bdev = wc->ssd_dev->bdev;
+ region.sector = 0;
+ region.count = PAGE_SIZE;
+
+ if (unlikely(region.sector + region.count > wc->metadata_sectors))
+ region.count = wc->metadata_sectors - region.sector;
+
+ region.sector += wc->start_sector;
+
+ req.bi_op = REQ_OP_WRITE;
+ req.bi_op_flags = REQ_SYNC | REQ_FUA;
+ req.mem.type = DM_IO_VMA;
+ req.mem.ptr.vma = (char *)wc->memory_map;
+ req.client = wc->dm_io;
+ req.notify.fn = NULL;
+ req.notify.context = NULL;
+
+ r = dm_io(&req, 1, &region, NULL);
+ if (unlikely(r))
+ writecache_error(wc, r, "error writing superblock");
+}
+
static void writecache_commit_flushed(struct dm_writecache *wc, bool wait_for_ios)
{
if (WC_MODE_PMEM(wc))
@@ -759,8 +787,10 @@ static void writecache_flush(struct dm_writecache *wc)
wc->seq_count++;
pmem_assign(sb(wc)->seq_count, cpu_to_le64(wc->seq_count));
- writecache_flush_region(wc, &sb(wc)->seq_count, sizeof sb(wc)->seq_count);
- writecache_commit_flushed(wc, false);
+ if (WC_MODE_PMEM(wc))
+ writecache_commit_flushed(wc, false);
+ else
+ ssd_commit_superblock(wc);
wc->overwrote_committed = false;