This patch adds a "metadata_only" parameter. When it is present, only metadata are promoted to the cache. It improves performance in the "git checkout" benchmark from 341s to 312s.
Signed-off-by: Mikulas Patocka <[email protected]> Index: linux/drivers/md/dm-writecache.c =================================================================== --- linux.orig/drivers/md/dm-writecache.c +++ linux/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; @@ -1297,7 +1298,7 @@ static int writecache_map(struct dm_targ 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 { @@ -1376,7 +1377,7 @@ 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); @@ -2090,7 +2091,7 @@ static int writecache_ctr(struct dm_targ 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; @@ -2317,6 +2318,8 @@ static int writecache_ctr(struct dm_targ 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; @@ -2540,6 +2543,8 @@ static void writecache_status(struct dm_ extra_args++; if (wc->writeback_fua_set) extra_args++; + if (wc->metadata_only) + extra_args++; DMEMIT("%u", extra_args); if (wc->start_sector_set) @@ -2560,13 +2565,15 @@ static void writecache_status(struct dm_ 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, -- dm-devel mailing list [email protected] https://listman.redhat.com/mailman/listinfo/dm-devel
