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authorMike Snitzer <snitzer@redhat.com>2017-12-12 07:17:47 +0300
committerMike Snitzer <snitzer@redhat.com>2017-12-17 04:43:13 +0300
commit64f52b0e31489b46465cff2e61ab2e1f60a3b4eb (patch)
treedf8fa456e546efbff6aa8bf39157a18caf32047e /include/linux/device-mapper.h
parent745dc570b2c379730d2a78acdeb65b5239e833c6 (diff)
downloadlinux-64f52b0e31489b46465cff2e61ab2e1f60a3b4eb.tar.xz
dm: improve performance by moving dm_io structure to per-bio-data
Eliminates need for a separate mempool to allocate 'struct dm_io' objects from. As such, it saves an extra mempool allocation for each original bio that DM core is issued. This complicates the per-bio-data accessor functions by needing to conditonally add extra padding to get to a target's per-bio-data. But in the end this provides a decent performance improvement for all bio-based DM devices. On an NVMe-loop based testbed to a ramdisk (~3100 MB/s): bio-based DM linear performance improved by 2% (went from 2665 to 2777 MB/s). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'include/linux/device-mapper.h')
-rw-r--r--include/linux/device-mapper.h32
1 files changed, 3 insertions, 29 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 5a68b366e664..0e518d2ee280 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -314,35 +314,9 @@ struct dm_target_callbacks {
int (*congested_fn) (struct dm_target_callbacks *, int);
};
-/*
- * For bio-based dm.
- * One of these is allocated for each bio.
- * This structure shouldn't be touched directly by target drivers.
- * It is here so that we can inline dm_per_bio_data and
- * dm_bio_from_per_bio_data
- */
-struct dm_target_io {
- struct dm_io *io;
- struct dm_target *ti;
- unsigned target_bio_nr;
- unsigned *len_ptr;
- struct bio clone;
-};
-
-static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
-{
- return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
-}
-
-static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
-{
- return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
-}
-
-static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
-{
- return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
-}
+void *dm_per_bio_data(struct bio *bio, size_t data_size);
+struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size);
+unsigned dm_bio_get_target_bio_nr(const struct bio *bio);
int dm_register_target(struct target_type *t);
void dm_unregister_target(struct target_type *t);