From fb89e89d0ff6142f0616eb8260ea89d6fd924982 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 10 Jun 2009 04:38:41 +0000 Subject: [PATCH] ps3vram: Replace mutex by spinlock + bio_list Remove the mutex serializing access to the cache. Instead, queue up new requests on a bio_list if the driver is busy. This improves sequential write performance by ca. 2%. Signed-off-by: Geert Uytterhoeven Cc: Jim Paris Cc: Jens Axboe Signed-off-by: Benjamin Herrenschmidt --- drivers/block/ps3vram.c | 51 +++++++++++++++++++++++++++++------------ 1 file changed, 36 insertions(+), 15 deletions(-) diff --git a/drivers/block/ps3vram.c b/drivers/block/ps3vram.c index 2c2ea9cb207b..7d1c742d6d66 100644 --- a/drivers/block/ps3vram.c +++ b/drivers/block/ps3vram.c @@ -81,8 +81,8 @@ struct ps3vram_priv { struct ps3vram_cache cache; - /* Used to serialize cache/DMA operations */ - struct mutex lock; + spinlock_t lock; /* protecting list of bios */ + struct bio_list list; }; @@ -443,8 +443,6 @@ static int ps3vram_read(struct ps3_system_bus_device *dev, loff_t from, offset = (unsigned int) (from & (priv->cache.page_size - 1)); avail = priv->cache.page_size - offset; - mutex_lock(&priv->lock); - entry = ps3vram_cache_match(dev, from); cached = CACHE_OFFSET + entry * priv->cache.page_size + offset; @@ -456,8 +454,6 @@ static int ps3vram_read(struct ps3_system_bus_device *dev, loff_t from, avail = count; memcpy(buf, priv->xdr_buf + cached, avail); - mutex_unlock(&priv->lock); - buf += avail; count -= avail; from += avail; @@ -488,8 +484,6 @@ static int ps3vram_write(struct ps3_system_bus_device *dev, loff_t to, offset = (unsigned int) (to & (priv->cache.page_size - 1)); avail = priv->cache.page_size - offset; - mutex_lock(&priv->lock); - entry = ps3vram_cache_match(dev, to); cached = CACHE_OFFSET + entry * priv->cache.page_size + offset; @@ -503,8 +497,6 @@ static int ps3vram_write(struct ps3_system_bus_device *dev, loff_t to, priv->cache.tags[entry].flags |= CACHE_PAGE_DIRTY; - mutex_unlock(&priv->lock); - buf += avail; count -= avail; to += avail; @@ -546,17 +538,17 @@ static void __devinit ps3vram_proc_init(struct ps3_system_bus_device *dev) dev_warn(&dev->core, "failed to create /proc entry\n"); } -static int ps3vram_make_request(struct request_queue *q, struct bio *bio) +static struct bio *ps3vram_do_bio(struct ps3_system_bus_device *dev, + struct bio *bio) { - struct ps3_system_bus_device *dev = q->queuedata; + struct ps3vram_priv *priv = dev->core.driver_data; int write = bio_data_dir(bio) == WRITE; const char *op = write ? "write" : "read"; loff_t offset = bio->bi_sector << 9; int error = 0; struct bio_vec *bvec; unsigned int i; - - dev_dbg(&dev->core, "%s\n", __func__); + struct bio *next; bio_for_each_segment(bvec, bio, i) { /* PS3 is ppc64, so we don't handle highmem */ @@ -587,7 +579,35 @@ static int ps3vram_make_request(struct request_queue *q, struct bio *bio) dev_dbg(&dev->core, "%s completed\n", op); out: + spin_lock_irq(&priv->lock); + bio_list_pop(&priv->list); + next = bio_list_peek(&priv->list); + spin_unlock_irq(&priv->lock); + bio_endio(bio, error); + return next; +} + +static int ps3vram_make_request(struct request_queue *q, struct bio *bio) +{ + struct ps3_system_bus_device *dev = q->queuedata; + struct ps3vram_priv *priv = dev->core.driver_data; + int busy; + + dev_dbg(&dev->core, "%s\n", __func__); + + spin_lock_irq(&priv->lock); + busy = !bio_list_empty(&priv->list); + bio_list_add(&priv->list, bio); + spin_unlock_irq(&priv->lock); + + if (busy) + return 0; + + do { + bio = ps3vram_do_bio(dev, bio); + } while (bio); + return 0; } @@ -607,7 +627,8 @@ static int __devinit ps3vram_probe(struct ps3_system_bus_device *dev) goto fail; } - mutex_init(&priv->lock); + spin_lock_init(&priv->lock); + bio_list_init(&priv->list); dev->core.driver_data = priv; priv = dev->core.driver_data;