From f722063ee01c0060488e1000006405449451cfa0 Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Fri, 9 Aug 2013 13:04:56 +0100 Subject: [PATCH] dm space map: optimise sm_ll_dec and sm_ll_inc Prior to this patch these methods did a lookup followed by an insert. Instead they now call a common mutate function that adjusts the value according to a callback function. This avoids traversing the data structures twice and hence improves performance. Also factor out sm_ll_lookup_big_ref_count() for use by both sm_ll_lookup() and sm_ll_mutate(). Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon --- .../md/persistent-data/dm-space-map-common.c | 77 ++++++++++++------- 1 file changed, 49 insertions(+), 28 deletions(-) diff --git a/drivers/md/persistent-data/dm-space-map-common.c b/drivers/md/persistent-data/dm-space-map-common.c index 3e7a88d99eb0..6058569fe86c 100644 --- a/drivers/md/persistent-data/dm-space-map-common.c +++ b/drivers/md/persistent-data/dm-space-map-common.c @@ -292,16 +292,11 @@ int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result) return dm_tm_unlock(ll->tm, blk); } -int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result) +static int sm_ll_lookup_big_ref_count(struct ll_disk *ll, dm_block_t b, + uint32_t *result) { __le32 le_rc; - int r = sm_ll_lookup_bitmap(ll, b, result); - - if (r) - return r; - - if (*result != 3) - return r; + int r; r = dm_btree_lookup(&ll->ref_count_info, ll->ref_count_root, &b, &le_rc); if (r < 0) @@ -312,6 +307,19 @@ int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result) return r; } +int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result) +{ + int r = sm_ll_lookup_bitmap(ll, b, result); + + if (r) + return r; + + if (*result != 3) + return r; + + return sm_ll_lookup_big_ref_count(ll, b, result); +} + int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin, dm_block_t end, dm_block_t *result) { @@ -372,11 +380,12 @@ int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin, return -ENOSPC; } -int sm_ll_insert(struct ll_disk *ll, dm_block_t b, - uint32_t ref_count, enum allocation_event *ev) +static int sm_ll_mutate(struct ll_disk *ll, dm_block_t b, + uint32_t (*mutator)(void *context, uint32_t old), + void *context, enum allocation_event *ev) { int r; - uint32_t bit, old; + uint32_t bit, old, ref_count; struct dm_block *nb; dm_block_t index = b; struct disk_index_entry ie_disk; @@ -399,6 +408,14 @@ int sm_ll_insert(struct ll_disk *ll, dm_block_t b, bm_le = dm_bitmap_data(nb); old = sm_lookup_bitmap(bm_le, bit); + if (old > 2) { + r = sm_ll_lookup_big_ref_count(ll, b, &old); + if (r < 0) + return r; + } + + ref_count = mutator(context, old); + if (ref_count <= 2) { sm_set_bitmap(bm_le, bit, ref_count); @@ -448,31 +465,35 @@ int sm_ll_insert(struct ll_disk *ll, dm_block_t b, return ll->save_ie(ll, index, &ie_disk); } -int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) +static uint32_t set_ref_count(void *context, uint32_t old) { - int r; - uint32_t rc; - - r = sm_ll_lookup(ll, b, &rc); - if (r) - return r; + return *((uint32_t *) context); +} - return sm_ll_insert(ll, b, rc + 1, ev); +int sm_ll_insert(struct ll_disk *ll, dm_block_t b, + uint32_t ref_count, enum allocation_event *ev) +{ + return sm_ll_mutate(ll, b, set_ref_count, &ref_count, ev); } -int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) +static uint32_t inc_ref_count(void *context, uint32_t old) { - int r; - uint32_t rc; + return old + 1; +} - r = sm_ll_lookup(ll, b, &rc); - if (r) - return r; +int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) +{ + return sm_ll_mutate(ll, b, inc_ref_count, NULL, ev); +} - if (!rc) - return -EINVAL; +static uint32_t dec_ref_count(void *context, uint32_t old) +{ + return old - 1; +} - return sm_ll_insert(ll, b, rc - 1, ev); +int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) +{ + return sm_ll_mutate(ll, b, dec_ref_count, NULL, ev); } int sm_ll_commit(struct ll_disk *ll) -- 2.20.1