[dm-devel] [PATCH] dm-cache: replace spin_lock_irqsave with spin_lock_irq
Mikulas Patocka
mpatocka at redhat.com
Wed Oct 23 13:39:15 UTC 2019
If we are in a place where it is known that interrupts are enabled,
functions spin_lock_irq/spin_unlock_irq should be used instead of
spin_lock_irqsave/spin_unlock_irqrestore.
spin_lock_irq and spin_unlock_irq are faster because the don't need to
push and pop the flags register.
Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
---
drivers/md/dm-cache-target.c | 99 ++++++++++++-------------------------------
1 file changed, 28 insertions(+), 71 deletions(-)
Index: linux-2.6/drivers/md/dm-cache-target.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-cache-target.c 2019-10-16 17:05:31.000000000 +0200
+++ linux-2.6/drivers/md/dm-cache-target.c 2019-10-16 17:09:35.000000000 +0200
@@ -74,22 +74,19 @@ static bool __iot_idle_for(struct io_tra
static bool iot_idle_for(struct io_tracker *iot, unsigned long jifs)
{
bool r;
- unsigned long flags;
- spin_lock_irqsave(&iot->lock, flags);
+ spin_lock_irq(&iot->lock);
r = __iot_idle_for(iot, jifs);
- spin_unlock_irqrestore(&iot->lock, flags);
+ spin_unlock_irq(&iot->lock);
return r;
}
static void iot_io_begin(struct io_tracker *iot, sector_t len)
{
- unsigned long flags;
-
- spin_lock_irqsave(&iot->lock, flags);
+ spin_lock_irq(&iot->lock);
iot->in_flight += len;
- spin_unlock_irqrestore(&iot->lock, flags);
+ spin_unlock_irq(&iot->lock);
}
static void __iot_io_end(struct io_tracker *iot, sector_t len)
@@ -172,7 +169,6 @@ static void __commit(struct work_struct
{
struct batcher *b = container_of(_ws, struct batcher, commit_work);
blk_status_t r;
- unsigned long flags;
struct list_head work_items;
struct work_struct *ws, *tmp;
struct continuation *k;
@@ -186,12 +182,12 @@ static void __commit(struct work_struct
* We have to grab these before the commit_op to avoid a race
* condition.
*/
- spin_lock_irqsave(&b->lock, flags);
+ spin_lock_irq(&b->lock);
list_splice_init(&b->work_items, &work_items);
bio_list_merge(&bios, &b->bios);
bio_list_init(&b->bios);
b->commit_scheduled = false;
- spin_unlock_irqrestore(&b->lock, flags);
+ spin_unlock_irq(&b->lock);
r = b->commit_op(b->commit_context);
@@ -238,13 +234,12 @@ static void async_commit(struct batcher
static void continue_after_commit(struct batcher *b, struct continuation *k)
{
- unsigned long flags;
bool commit_scheduled;
- spin_lock_irqsave(&b->lock, flags);
+ spin_lock_irq(&b->lock);
commit_scheduled = b->commit_scheduled;
list_add_tail(&k->ws.entry, &b->work_items);
- spin_unlock_irqrestore(&b->lock, flags);
+ spin_unlock_irq(&b->lock);
if (commit_scheduled)
async_commit(b);
@@ -255,13 +250,12 @@ static void continue_after_commit(struct
*/
static void issue_after_commit(struct batcher *b, struct bio *bio)
{
- unsigned long flags;
bool commit_scheduled;
- spin_lock_irqsave(&b->lock, flags);
+ spin_lock_irq(&b->lock);
commit_scheduled = b->commit_scheduled;
bio_list_add(&b->bios, bio);
- spin_unlock_irqrestore(&b->lock, flags);
+ spin_unlock_irq(&b->lock);
if (commit_scheduled)
async_commit(b);
@@ -273,12 +267,11 @@ static void issue_after_commit(struct ba
static void schedule_commit(struct batcher *b)
{
bool immediate;
- unsigned long flags;
- spin_lock_irqsave(&b->lock, flags);
+ spin_lock_irq(&b->lock);
immediate = !list_empty(&b->work_items) || !bio_list_empty(&b->bios);
b->commit_scheduled = true;
- spin_unlock_irqrestore(&b->lock, flags);
+ spin_unlock_irq(&b->lock);
if (immediate)
async_commit(b);
@@ -630,23 +623,19 @@ static struct per_bio_data *init_per_bio
static void defer_bio(struct cache *cache, struct bio *bio)
{
- unsigned long flags;
-
- spin_lock_irqsave(&cache->lock, flags);
+ spin_lock_irq(&cache->lock);
bio_list_add(&cache->deferred_bios, bio);
- spin_unlock_irqrestore(&cache->lock, flags);
+ spin_unlock_irq(&cache->lock);
wake_deferred_bio_worker(cache);
}
static void defer_bios(struct cache *cache, struct bio_list *bios)
{
- unsigned long flags;
-
- spin_lock_irqsave(&cache->lock, flags);
+ spin_lock_irq(&cache->lock);
bio_list_merge(&cache->deferred_bios, bios);
bio_list_init(bios);
- spin_unlock_irqrestore(&cache->lock, flags);
+ spin_unlock_irq(&cache->lock);
wake_deferred_bio_worker(cache);
}
@@ -662,10 +651,6 @@ static bool bio_detain_shared(struct cac
struct dm_bio_prison_cell_v2 *cell_prealloc, *cell;
cell_prealloc = alloc_prison_cell(cache); /* FIXME: allow wait if calling from worker */
- if (!cell_prealloc) {
- defer_bio(cache, bio);
- return false;
- }
build_key(oblock, end, &key);
r = dm_cell_get_v2(cache->prison, &key, lock_level(bio), bio, cell_prealloc, &cell);
@@ -760,33 +745,27 @@ static dm_dblock_t oblock_to_dblock(stru
static void set_discard(struct cache *cache, dm_dblock_t b)
{
- unsigned long flags;
-
BUG_ON(from_dblock(b) >= from_dblock(cache->discard_nr_blocks));
atomic_inc(&cache->stats.discard_count);
- spin_lock_irqsave(&cache->lock, flags);
+ spin_lock_irq(&cache->lock);
set_bit(from_dblock(b), cache->discard_bitset);
- spin_unlock_irqrestore(&cache->lock, flags);
+ spin_unlock_irq(&cache->lock);
}
static void clear_discard(struct cache *cache, dm_dblock_t b)
{
- unsigned long flags;
-
- spin_lock_irqsave(&cache->lock, flags);
+ spin_lock_irq(&cache->lock);
clear_bit(from_dblock(b), cache->discard_bitset);
- spin_unlock_irqrestore(&cache->lock, flags);
+ spin_unlock_irq(&cache->lock);
}
static bool is_discarded(struct cache *cache, dm_dblock_t b)
{
int r;
- unsigned long flags;
-
- spin_lock_irqsave(&cache->lock, flags);
+ spin_lock_irq(&cache->lock);
r = test_bit(from_dblock(b), cache->discard_bitset);
- spin_unlock_irqrestore(&cache->lock, flags);
+ spin_unlock_irq(&cache->lock);
return r;
}
@@ -794,12 +773,10 @@ static bool is_discarded(struct cache *c
static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b)
{
int r;
- unsigned long flags;
-
- spin_lock_irqsave(&cache->lock, flags);
+ spin_lock_irq(&cache->lock);
r = test_bit(from_dblock(oblock_to_dblock(cache, b)),
cache->discard_bitset);
- spin_unlock_irqrestore(&cache->lock, flags);
+ spin_unlock_irq(&cache->lock);
return r;
}
@@ -831,17 +808,16 @@ static void remap_to_cache(struct cache
static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)
{
- unsigned long flags;
struct per_bio_data *pb;
- spin_lock_irqsave(&cache->lock, flags);
+ spin_lock_irq(&cache->lock);
if (cache->need_tick_bio && !op_is_flush(bio->bi_opf) &&
bio_op(bio) != REQ_OP_DISCARD) {
pb = get_per_bio_data(bio);
pb->tick = true;
cache->need_tick_bio = false;
}
- spin_unlock_irqrestore(&cache->lock, flags);
+ spin_unlock_irq(&cache->lock);
}
static void __remap_to_origin_clear_discard(struct cache *cache, struct bio *bio,
@@ -1491,11 +1467,6 @@ static int mg_lock_writes(struct dm_cach
struct dm_bio_prison_cell_v2 *prealloc;
prealloc = alloc_prison_cell(cache);
- if (!prealloc) {
- DMERR_LIMIT("%s: alloc_prison_cell failed", cache_device_name(cache));
- mg_complete(mg, false);
- return -ENOMEM;
- }
/*
* Prevent writes to the block, but allow reads to continue.
@@ -1533,11 +1504,6 @@ static int mg_start(struct cache *cache,
}
mg = alloc_migration(cache);
- if (!mg) {
- policy_complete_background_work(cache->policy, op, false);
- background_work_end(cache);
- return -ENOMEM;
- }
mg->op = op;
mg->overwrite_bio = bio;
@@ -1626,10 +1592,6 @@ static int invalidate_lock(struct dm_cac
struct dm_bio_prison_cell_v2 *prealloc;
prealloc = alloc_prison_cell(cache);
- if (!prealloc) {
- invalidate_complete(mg, false);
- return -ENOMEM;
- }
build_key(mg->invalidate_oblock, oblock_succ(mg->invalidate_oblock), &key);
r = dm_cell_lock_v2(cache->prison, &key,
@@ -1667,10 +1629,6 @@ static int invalidate_start(struct cache
return -EPERM;
mg = alloc_migration(cache);
- if (!mg) {
- background_work_end(cache);
- return -ENOMEM;
- }
mg->overwrite_bio = bio;
mg->invalidate_cblock = cblock;
@@ -1911,17 +1869,16 @@ static void process_deferred_bios(struct
{
struct cache *cache = container_of(ws, struct cache, deferred_bio_worker);
- unsigned long flags;
bool commit_needed = false;
struct bio_list bios;
struct bio *bio;
bio_list_init(&bios);
- spin_lock_irqsave(&cache->lock, flags);
+ spin_lock_irq(&cache->lock);
bio_list_merge(&bios, &cache->deferred_bios);
bio_list_init(&cache->deferred_bios);
- spin_unlock_irqrestore(&cache->lock, flags);
+ spin_unlock_irq(&cache->lock);
while ((bio = bio_list_pop(&bios))) {
if (bio->bi_opf & REQ_PREFLUSH)
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