github/open-cas-linux
4
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Remove potentially_dirty counter from bottom volume

Browse Source 
This counter is not accurate (missing required memory barrier
to avoid unwanted behavior due to processor optimizations)
and performance gain is not clear - generally global
atomic variables are something we would like to avoid
going forward.

Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
This commit is contained in:
Adam Rutkowski
2020-09-28 14:14:22 +02:00
parent 3ea056eb30
commit 7905ca79fa
4 changed files with 3 additions and 73 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
modules/cas_cache/volume/vol_atomic_dev_bottom.c
View File

@@ -35,7 +35,6 @@ struct cas_atomic_io {
struct cas_atomic_io *master;
atomic_t req_remaining;
atomic_t potential_dirty;
uint32_t count;
uint64_t addr;
@@ -463,23 +462,8 @@ static CAS_DECLARE_BLOCK_CALLBACK(cas_atomic_fire_atom, struct bio *bio,
goto out;
}
switch (atom->dir) {
case OCF_READ:
if (cas_atomic_rd_complete(atom))
atom->master->error = -EIO;
break;
case OCF_WRITE:
if (!cas_blk_is_flush_io(atom->flags)) {
atomic_inc(&bdobj->potentially_dirty);
} else {
/* IO flush finished, update potential
* dirty state
*/
atomic_sub(atomic_read(&atom->potential_dirty),
&bdobj->potentially_dirty);
}
break;
}
if (atom->dir == OCF_READ && cas_atomic_rd_complete(atom))
atom->master->error = -EIO;
out:
/* Free BIO, no needed any more */
@@ -858,16 +842,6 @@ void cas_atomic_submit_flush(struct ocf_io *io)
CAS_DEBUG_TRACE();
blkio->dirty = atomic_read(&bdobj->potentially_dirty);
if (!blkio->dirty) {
/* Didn't write anything to underlying disk;
* no need to send req_flush
*/
io->end(io, 0);
return;
}
if (!q) {
io->end(io, -EINVAL);
return;
@@ -875,7 +849,6 @@ void cas_atomic_submit_flush(struct ocf_io *io)
if (!CAS_CHECK_QUEUE_FLUSH(q)) {
/* This block device does not support flush */
atomic_sub(blkio->dirty, &bdobj->potentially_dirty);
io->end(io, 0);
return;
}
@@ -900,7 +873,6 @@ void cas_atomic_submit_flush(struct ocf_io *io)
/* Set up specific field */
atom->dir = OCF_WRITE;
atomic_set(&atom->potential_dirty, blkio->dirty);
atom->request = cas_blk_make_request(q, atom->bio, GFP_NOIO);
if (IS_ERR(atom->request)) {