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authorMikulas Patocka <mpatocka@redhat.com>2021-06-21 05:22:21 -0400
committerMike Snitzer <snitzer@redhat.com>2021-06-25 15:25:21 -0400
commit611c3e168b1c5b6cf81e6deb8f6b4eb83f6b53fd (patch)
tree0cd47db943f892db1caa04512e9987af82284653
parentcd039afa0ad86e1f01921cc5abf7f80d2449543a (diff)
dm writecache: add optional "metadata_only" parameter
Add a "metadata_only" parameter that when present: only metadata is promoted to the cache. This option improves performance for heavier REQ_META workloads (e.g. device-mapper-test-suite's "git clone and checkout" benchmark improves from 341s to 312s). Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
-rw-r--r--Documentation/admin-guide/device-mapper/writecache.rst3
-rw-r--r--drivers/md/dm-writecache.c16
2 files changed, 15 insertions, 4 deletions
diff --git a/Documentation/admin-guide/device-mapper/writecache.rst b/Documentation/admin-guide/device-mapper/writecache.rst
index c181f26af769..977f82b5a811 100644
--- a/Documentation/admin-guide/device-mapper/writecache.rst
+++ b/Documentation/admin-guide/device-mapper/writecache.rst
@@ -68,6 +68,9 @@ Constructor parameters:
specifies the maximum age of a block in milliseconds. If
a block is stored in the cache for too long, it will be
written to the underlying device and cleaned up.
+ metadata_only
+ only metadata is promoted to the cache. This option
+ improves performance for heavier REQ_META workloads.
Status:
1. error indicator - 0 if there was no error, otherwise error number
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 558d39764e6d..2eb7d7bcdfb1 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -171,6 +171,7 @@ struct dm_writecache {
bool flush_on_suspend:1;
bool cleaner:1;
bool cleaner_set:1;
+ bool metadata_only:1;
unsigned high_wm_percent_value;
unsigned low_wm_percent_value;
@@ -1301,7 +1302,7 @@ static int writecache_map(struct dm_target *ti, struct bio *bio)
writecache_flush(wc);
if (writecache_has_error(wc))
goto unlock_error;
- if (unlikely(wc->cleaner))
+ if (unlikely(wc->cleaner) || unlikely(wc->metadata_only))
goto unlock_remap_origin;
goto unlock_submit;
} else {
@@ -1380,7 +1381,8 @@ read_next_block:
}
found_entry = true;
} else {
- if (unlikely(wc->cleaner))
+ if (unlikely(wc->cleaner) ||
+ (wc->metadata_only && !(bio->bi_opf & REQ_META)))
goto direct_write;
}
e = writecache_pop_from_freelist(wc, (sector_t)-1);
@@ -2094,7 +2096,7 @@ static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
struct wc_memory_superblock s;
static struct dm_arg _args[] = {
- {0, 16, "Invalid number of feature args"},
+ {0, 17, "Invalid number of feature args"},
};
as.argc = argc;
@@ -2321,6 +2323,8 @@ static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
wc->writeback_fua = false;
wc->writeback_fua_set = true;
} else goto invalid_optional;
+ } else if (!strcasecmp(string, "metadata_only")) {
+ wc->metadata_only = true;
} else {
invalid_optional:
r = -EINVAL;
@@ -2544,6 +2548,8 @@ static void writecache_status(struct dm_target *ti, status_type_t type,
extra_args++;
if (wc->writeback_fua_set)
extra_args++;
+ if (wc->metadata_only)
+ extra_args++;
DMEMIT("%u", extra_args);
if (wc->start_sector_set)
@@ -2564,13 +2570,15 @@ static void writecache_status(struct dm_target *ti, status_type_t type,
DMEMIT(" cleaner");
if (wc->writeback_fua_set)
DMEMIT(" %sfua", wc->writeback_fua ? "" : "no");
+ if (wc->metadata_only)
+ DMEMIT(" metadata_only");
break;
}
}
static struct target_type writecache_target = {
.name = "writecache",
- .version = {1, 4, 0},
+ .version = {1, 5, 0},
.module = THIS_MODULE,
.ctr = writecache_ctr,
.dtr = writecache_dtr,