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authorChristoph Hellwig <hch@lst.de>2015-05-22 16:14:04 +0300
committerJens Axboe <axboe@fb.com>2015-05-22 17:58:57 +0300
commit5f1b670d0bef508a5554d92525f5f6d00d640b38 (patch)
tree18aaa4b5ead87568214b3d9c0f501d8a98c2a787 /drivers/md/dm.h
parent326e1dbb57368087a36607aaebe9795b8d5453e5 (diff)
downloadlinux-5f1b670d0bef508a5554d92525f5f6d00d640b38.tar.xz
block, dm: don't copy bios for request clones
Currently dm-multipath has to clone the bios for every request sent to the lower devices, which wastes cpu cycles and ties down memory. This patch instead adds a new REQ_CLONE flag that instructs req_bio_endio to not complete bios attached to a request, which we set on clone requests similar to bios in a flush sequence. With this change I/O errors on a path failure only get propagated to dm-multipath, which can then either resubmit the I/O or complete the bios on the original request. I've done some basic testing of this on a Linux target with ALUA support, and it survives path failures during I/O nicely. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/md/dm.h')
-rw-r--r--drivers/md/dm.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 6123c2bf9150..e6e66d087b26 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -222,8 +222,9 @@ void dm_kcopyd_exit(void);
/*
* Mempool operations
*/
-struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned type,
- unsigned integrity, unsigned per_bio_data_size);
+struct dm_md_mempools *dm_alloc_bio_mempools(unsigned integrity,
+ unsigned per_bio_data_size);
+struct dm_md_mempools *dm_alloc_rq_mempools(struct mapped_device *md, unsigned type);
void dm_free_md_mempools(struct dm_md_mempools *pools);
/*