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| author | Mikulas Patocka <mpatocka@redhat.com> | 2009-12-10 23:51:59 +0000 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-12-10 23:51:59 +0000 |
| commit | b09acf1aa79462bdacfe6744b469a17722a52702 (patch) | |
| tree | 27ef83ed0d0bbf35938814f8ba3206e7881a170d /drivers/md/dm-log.c | |
| parent | 4184153f9e483f9bb63339ed316e059962fe9794 (diff) | |
| download | linux-b09acf1aa79462bdacfe6744b469a17722a52702.tar.bz2 | |
dm raid1: split touched state into two
Split the variable "touched" into two, "touched_dirtied" and
"touched_cleaned", set when some region was dirtied or cleaned.
This will be used to optimize flushes.
After a transition from "dirty" to "clean" state we don't have flush hardware
cache on the log device. After a transition from "clean" to "dirty" the cache
must be flushed.
Before a transition from "clean" to "dirty" state we don't have to flush all
the raid legs. Before a transition from "dirty" to "clean" we must flush all
the legs to make sure that they are really in sync.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-log.c')
| -rw-r--r-- | drivers/md/dm-log.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c index 9443896ede07..31dc33df95c7 100644 --- a/drivers/md/dm-log.c +++ b/drivers/md/dm-log.c @@ -208,7 +208,8 @@ struct log_header { struct log_c { struct dm_target *ti; - int touched; + int touched_dirtied; + int touched_cleaned; uint32_t region_size; unsigned int region_count; region_t sync_count; @@ -253,14 +254,14 @@ static inline void log_set_bit(struct log_c *l, uint32_t *bs, unsigned bit) { ext2_set_bit(bit, (unsigned long *) bs); - l->touched = 1; + l->touched_cleaned = 1; } static inline void log_clear_bit(struct log_c *l, uint32_t *bs, unsigned bit) { ext2_clear_bit(bit, (unsigned long *) bs); - l->touched = 1; + l->touched_dirtied = 1; } /*---------------------------------------------------------------- @@ -378,7 +379,8 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti, } lc->ti = ti; - lc->touched = 0; + lc->touched_dirtied = 0; + lc->touched_cleaned = 0; lc->region_size = region_size; lc->region_count = region_count; lc->sync = sync; @@ -660,14 +662,16 @@ static int disk_flush(struct dm_dirty_log *log) struct log_c *lc = (struct log_c *) log->context; /* only write if the log has changed */ - if (!lc->touched) + if (!lc->touched_cleaned && !lc->touched_dirtied) return 0; r = rw_header(lc, WRITE); if (r) fail_log_device(lc); - else - lc->touched = 0; + else { + lc->touched_dirtied = 0; + lc->touched_cleaned = 0; + } return r; } |