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Commit fb89e89d authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Benjamin Herrenschmidt
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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: default avatarGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: Jim Paris <jim@jtan.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 13685a16

drivers/block/ps3vram.c

+36 −15
Original line number Original line Diff line number Diff line
@@ -81,8 +81,8 @@ struct ps3vram_priv { 




	struct ps3vram_cache cache;

	struct ps3vram_cache cache;





	/* Used to serialize cache/DMA operations */

	spinlock_t lock;	/* protecting list of bios */

	struct mutex lock;

	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));

		offset = (unsigned int) (from & (priv->cache.page_size - 1));

		avail  = priv->cache.page_size - offset;

		avail  = priv->cache.page_size - offset;





		mutex_lock(&priv->lock);



		entry = ps3vram_cache_match(dev, from);

		entry = ps3vram_cache_match(dev, from);

		cached = CACHE_OFFSET + entry * priv->cache.page_size + offset;

		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;

			avail = count;

		memcpy(buf, priv->xdr_buf + cached, avail);

		memcpy(buf, priv->xdr_buf + cached, avail);





		mutex_unlock(&priv->lock);



		buf += avail;

		buf += avail;

		count -= avail;

		count -= avail;

		from += 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));

		offset = (unsigned int) (to & (priv->cache.page_size - 1));

		avail  = priv->cache.page_size - offset;

		avail  = priv->cache.page_size - offset;





		mutex_lock(&priv->lock);



		entry = ps3vram_cache_match(dev, to);

		entry = ps3vram_cache_match(dev, to);

		cached = CACHE_OFFSET + entry * priv->cache.page_size + offset;

		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;

		priv->cache.tags[entry].flags |= CACHE_PAGE_DIRTY;





		mutex_unlock(&priv->lock);



		buf += avail;

		buf += avail;

		count -= avail;

		count -= avail;

		to += 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");

		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;

	int write = bio_data_dir(bio) == WRITE;

	const char *op = write ? "write" : "read";

	const char *op = write ? "write" : "read";

	loff_t offset = bio->bi_sector << 9;

	loff_t offset = bio->bi_sector << 9;

	int error = 0;

	int error = 0;

	struct bio_vec *bvec;

	struct bio_vec *bvec;

	unsigned int i;

	unsigned int i;



	struct bio *next;

	dev_dbg(&dev->core, "%s\n", __func__);





	bio_for_each_segment(bvec, bio, i) {

	bio_for_each_segment(bvec, bio, i) {

		/* PS3 is ppc64, so we don't handle highmem */

		/* 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);

	dev_dbg(&dev->core, "%s completed\n", op);





out:

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);

	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;

	return 0;

}

}
@@ -607,7 +627,8 @@ static int __devinit ps3vram_probe(struct ps3_system_bus_device *dev) 
		goto fail;

		goto fail;

	}

	}





	mutex_init(&priv->lock);

	spin_lock_init(&priv->lock);

	bio_list_init(&priv->list);

	dev->core.driver_data = priv;

	dev->core.driver_data = priv;





	priv = dev->core.driver_data;

	priv = dev->core.driver_data;