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| author | Tony Breeds <tony@bakeyournoodle.com> | 2014-09-26 09:14:12 +1000 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2014-10-20 13:41:26 +0200 |
| commit | 7c15903789953ead14a417882657d52dc0c19a24 (patch) | |
| tree | 9e60d44c6875465077818bc74285f895c8321d87 | |
| parent | 38c4d0aea3e1264c86e282d99560330adf2b6e25 (diff) | |
| download | qemu-7c15903789953ead14a417882657d52dc0c19a24.zip qemu-7c15903789953ead14a417882657d52dc0c19a24.tar.gz qemu-7c15903789953ead14a417882657d52dc0c19a24.tar.bz2 | |
block/raw-posix: use seek_hole ahead of fiemap
try_fiemap() uses FIEMAP_FLAG_SYNC which has a significant performance
impact.
Prefer seek_hole() over fiemap() to avoid this impact where possible.
seek_hole is more widely used and, arguably, has potential to be
optimised in the kernel.
Reported-By: Michael Steffens <michael_steffens@posteo.de>
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Max Reitz <mreitz@redhat.com>
Cc: Pádraig Brady <pbrady@redhat.com>
Cc: Eric Blake <eblake@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
| -rw-r--r-- | block/raw-posix.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/block/raw-posix.c b/block/raw-posix.c index d672c73..eb76f0e 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -1571,9 +1571,9 @@ static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs, start = sector_num * BDRV_SECTOR_SIZE; - ret = try_fiemap(bs, start, &data, &hole, nb_sectors, pnum); + ret = try_seek_hole(bs, start, &data, &hole, pnum); if (ret < 0) { - ret = try_seek_hole(bs, start, &data, &hole, pnum); + ret = try_fiemap(bs, start, &data, &hole, nb_sectors, pnum); if (ret < 0) { /* Assume everything is allocated. */ data = 0; |