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author | Paolo Bonzini <pbonzini@redhat.com> | 2023-04-07 17:33:03 +0200 |
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committer | Kevin Wolf <kwolf@redhat.com> | 2023-04-11 16:46:49 +0200 |
commit | 81f730d4d0e8af9c0211c3fedf406df0046341a9 (patch) | |
tree | e0d6ed4cd1dd736e9e4f1e6b2ba5bea0c3617d14 /block.c | |
parent | 9ed98cae151368cc89c4bb77c9f325f7185e8f09 (diff) | |
download | qemu-81f730d4d0e8af9c0211c3fedf406df0046341a9.zip qemu-81f730d4d0e8af9c0211c3fedf406df0046341a9.tar.gz qemu-81f730d4d0e8af9c0211c3fedf406df0046341a9.tar.bz2 |
block, block-backend: write some hot coroutine wrappers by hand
The introduction of the graph lock is causing blk_get_geometry, a hot function
used in the I/O path, to create a coroutine. However, the only part that really
needs to run in coroutine context is the call to bdrv_co_refresh_total_sectors,
which in turn only happens in the rare case of host CD-ROM devices.
So, write by hand the three wrappers on the path from blk_co_get_geometry to
bdrv_co_refresh_total_sectors, so that the coroutine wrapper is only created
if bdrv_nb_sectors actually calls bdrv_refresh_total_sectors.
Reported-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20230407153303.391121-9-pbonzini@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block.c')
-rw-r--r-- | block.c | 22 |
1 files changed, 22 insertions, 0 deletions
@@ -5859,6 +5859,28 @@ int64_t coroutine_fn bdrv_co_nb_sectors(BlockDriverState *bs) return bs->total_sectors; } +/* + * This wrapper is written by hand because this function is in the hot I/O path, + * via blk_get_geometry. + */ +int64_t coroutine_mixed_fn bdrv_nb_sectors(BlockDriverState *bs) +{ + BlockDriver *drv = bs->drv; + IO_CODE(); + + if (!drv) + return -ENOMEDIUM; + + if (bs->bl.has_variable_length) { + int ret = bdrv_refresh_total_sectors(bs, bs->total_sectors); + if (ret < 0) { + return ret; + } + } + + return bs->total_sectors; +} + /** * Return length in bytes on success, -errno on error. * The length is always a multiple of BDRV_SECTOR_SIZE. |