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 <geert.uytterhoe...@sonycom.com>
Cc: Jim Paris <j...@jtan.com>
Cc: Jens Axboe <ax...@kernel.dk>
---
v2: Use bio_list instead of homebrew single-linked list
drivers/block/ps3vram.c | 51 +++++++++++++++++++++++++++++++++-------------
1 files changed, 36 insertions(+), 15 deletions(-)
diff --git a/drivers/block/ps3vram.c b/drivers/block/ps3vram.c
index 3c9ad19..48c92ae 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;
};
@@ -449,8 +449,6 @@ 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;
@@ -462,8 +460,6 @@ 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;
@@ -494,8 +490,6 @@ 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;
@@ -509,8 +503,6 @@ 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;
@@ -552,17 +544,17 @@ 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 */
@@ -593,7 +585,35 @@ 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;
}
@@ -613,7 +633,8 @@ 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;
--
1.6.2.4
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