ACK: [PATCH 2/2] Revert "UBUNTU: SAUCE: Improve Amazon EBS performance for EC2"
Colin Ian King
colin.king at canonical.com
Mon Sep 17 15:29:16 UTC 2012
On 17/09/12 16:26, Stefan Bader wrote:
> This reverts commit d514f9334bc4f1097abfe5ecaf9ab091b8d0a18b as it
> is not needed/used.
>
> Signed-off-by: Stefan Bader <stefan.bader at canonical.com>
> ---
> drivers/block/xen-blkfront.c | 120 ++++++++++----------------------------
> include/xen/interface/io/blkif.h | 12 ----
> 2 files changed, 32 insertions(+), 100 deletions(-)
>
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index 43860d3..e4fb337 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -73,8 +73,7 @@ struct blk_shadow {
> static DEFINE_MUTEX(blkfront_mutex);
> static const struct block_device_operations xlvbd_block_fops;
>
> -#define BLK_MAX_RING_AREA_SIZE (BLKIF_MAX_NUM_RING_PAGES * PAGE_SIZE)
> -#define BLK_MAX_RING_SIZE __CONST_RING_SIZE(blkif, BLK_MAX_RING_AREA_SIZE)
> +#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
>
> /*
> * We have one of these per vbd, whether ide, scsi or 'other'. They
> @@ -90,15 +89,14 @@ struct blkfront_info
> int vdevice;
> blkif_vdev_t handle;
> enum blkif_state connected;
> - int num_ring_pages;
> - int ring_ref[BLKIF_MAX_NUM_RING_PAGES];
> + int ring_ref;
> struct blkif_front_ring ring;
> struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
> unsigned int evtchn, irq;
> struct request_queue *rq;
> struct work_struct work;
> struct gnttab_free_callback callback;
> - struct blk_shadow shadow[BLK_MAX_RING_SIZE];
> + struct blk_shadow shadow[BLK_RING_SIZE];
> unsigned long shadow_free;
> unsigned int feature_flush;
> unsigned int flush_op;
> @@ -137,8 +135,7 @@ static DEFINE_SPINLOCK(minor_lock);
> static int get_id_from_freelist(struct blkfront_info *info)
> {
> unsigned long free = info->shadow_free;
> - int ring_size = __RING_SIZE((struct blkif_sring *)0, info->num_ring_pages * PAGE_SIZE);
> - BUG_ON(free >= ring_size);
> + BUG_ON(free >= BLK_RING_SIZE);
> info->shadow_free = info->shadow[free].req.u.rw.id;
> info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
> return free;
> @@ -710,8 +707,6 @@ static void blkif_restart_queue(struct work_struct *work)
>
> static void blkif_free(struct blkfront_info *info, int suspend)
> {
> - int i;
> -
> /* Prevent new requests being issued until we fix things up. */
> spin_lock_irq(&info->io_lock);
> info->connected = suspend ?
> @@ -727,17 +722,10 @@ static void blkif_free(struct blkfront_info *info, int suspend)
> flush_work_sync(&info->work);
>
> /* Free resources associated with old device channel. */
> - for (i = 0; i < info->num_ring_pages; i++) {
> - /* Free resources associated with old device channel. */
> - if (info->ring_ref[i] != GRANT_INVALID_REF) {
> - gnttab_end_foreign_access(info->ring_ref[i], 0, 0L);
> - info->ring_ref[i] = GRANT_INVALID_REF;
> - }
> - }
> - if (info->ring.sring) {
> - int ring_area_size = info->num_ring_pages * PAGE_SIZE;
> - free_pages((unsigned long)info->ring.sring,
> - get_order(ring_area_size));
> + if (info->ring_ref != GRANT_INVALID_REF) {
> + gnttab_end_foreign_access(info->ring_ref, 0,
> + (unsigned long)info->ring.sring);
> + info->ring_ref = GRANT_INVALID_REF;
> info->ring.sring = NULL;
> }
> if (info->irq)
> @@ -874,32 +862,27 @@ static int setup_blkring(struct xenbus_device *dev,
> struct blkfront_info *info)
> {
> struct blkif_sring *sring;
> - int i, order, err;
> - int ring_area_size = info->num_ring_pages * PAGE_SIZE;
> + int err;
>
> - for (i = 0; i < info->num_ring_pages; i++) {
> - info->ring_ref[i] = GRANT_INVALID_REF;
> - }
> + info->ring_ref = GRANT_INVALID_REF;
>
> - order = get_order(ring_area_size);
> - sring = (struct blkif_sring *)__get_free_pages(GFP_KERNEL, order);
> + sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
> if (!sring) {
> xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
> return -ENOMEM;
> }
> SHARED_RING_INIT(sring);
> - FRONT_RING_INIT(&info->ring, sring, ring_area_size);
> -
> - for (i = 0; i < info->num_ring_pages; i++) {
> - unsigned long addr = (unsigned long)info->ring.sring + i * PAGE_SIZE;
> - err = xenbus_grant_ring(dev, virt_to_mfn(addr));
> - if (err < 0) {
> - free_pages((unsigned long)sring, order);
> - info->ring.sring = NULL;
> - goto fail;
> - }
> - info->ring_ref[i] = err;
> + FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
> +
> + sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
> +
> + err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
> + if (err < 0) {
> + free_page((unsigned long)sring);
> + info->ring.sring = NULL;
> + goto fail;
> }
> + info->ring_ref = err;
>
> err = xenbus_alloc_evtchn(dev, &info->evtchn);
> if (err)
> @@ -928,13 +911,7 @@ static int talk_to_blkback(struct xenbus_device *dev,
> {
> const char *message = NULL;
> struct xenbus_transaction xbt;
> - int err, i;
> -
> - BUILD_BUG_ON(BLKIF_MAX_NUM_RING_PAGES != 1 &&
> - BLKIF_MAX_NUM_RING_PAGES != 2 &&
> - BLKIF_MAX_NUM_RING_PAGES != 4 &&
> - BLKIF_MAX_NUM_RING_PAGES != 8 &&
> - BLKIF_MAX_NUM_RING_PAGES != 16);
> + int err;
>
> /* Create shared ring, alloc event channel. */
> err = setup_blkring(dev, info);
> @@ -948,30 +925,11 @@ again:
> goto destroy_blkring;
> }
>
> - if (info->num_ring_pages == 1) {
> - err = xenbus_printf(xbt, dev->nodename,
> - "ring-ref", "%u", info->ring_ref[0]);
> - if (err) {
> - message = "writing ring-ref";
> - goto abort_transaction;
> - }
> - } else {
> - err = xenbus_printf(xbt, dev->nodename, "num-ring-pages", "%u",
> - info->num_ring_pages);
> - if (err) {
> - message = "writing num-ring-pages";
> - goto abort_transaction;
> - }
> - for (i = 0; i < info->num_ring_pages; i++) {
> - char buf[16];
> - snprintf(buf, sizeof(buf), "ring-ref%d", i);
> - err = xenbus_printf(xbt, dev->nodename, buf, "%u",
> - info->ring_ref[i]);
> - if (err) {
> - message = "writing ring-refs";
> - goto abort_transaction;
> - }
> - }
> + err = xenbus_printf(xbt, dev->nodename,
> + "ring-ref", "%u", info->ring_ref);
> + if (err) {
> + message = "writing ring-ref";
> + goto abort_transaction;
> }
> err = xenbus_printf(xbt, dev->nodename,
> "event-channel", "%u", info->evtchn);
> @@ -1019,7 +977,6 @@ static int blkfront_probe(struct xenbus_device *dev,
> {
> int err, vdevice, i;
> struct blkfront_info *info;
> - int ring_size, max_ring_pages;
>
> /* FIXME: Use dynamic device id if this is not set. */
> err = xenbus_scanf(XBT_NIL, dev->nodename,
> @@ -1033,10 +990,6 @@ static int blkfront_probe(struct xenbus_device *dev,
> return err;
> }
> }
> - err = xenbus_scanf(XBT_NIL, dev->otherend,
> - "max-ring-pages", "%u", &max_ring_pages);
> - if (err != 1)
> - max_ring_pages = 1;
>
> if (xen_hvm_domain()) {
> char *type;
> @@ -1080,13 +1033,9 @@ static int blkfront_probe(struct xenbus_device *dev,
> info->connected = BLKIF_STATE_DISCONNECTED;
> INIT_WORK(&info->work, blkif_restart_queue);
>
> - info->num_ring_pages = min(max_ring_pages, BLKIF_MAX_NUM_RING_PAGES);
> -
> - ring_size = __RING_SIZE((struct blkif_sring *)0,
> - info->num_ring_pages * PAGE_SIZE);
> - for (i = 0; i < ring_size; i++)
> + for (i = 0; i < BLK_RING_SIZE; i++)
> info->shadow[i].req.u.rw.id = i+1;
> - info->shadow[ring_size-1].req.u.rw.id = 0x0fffffff;
> + info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
>
> /* Front end dir is a number, which is used as the id. */
> info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
> @@ -1099,9 +1048,6 @@ static int blkfront_probe(struct xenbus_device *dev,
> return err;
> }
>
> - printk(KERN_INFO "blkfront %s num-ring-pages %d nr_ents %d.\n",
> - dev->nodename, info->num_ring_pages, ring_size);
> -
> return 0;
> }
>
> @@ -1112,7 +1058,6 @@ static int blkif_recover(struct blkfront_info *info)
> struct blkif_request *req;
> struct blk_shadow *copy;
> int j;
> - int ring_size = __RING_SIZE((struct blkif_sring *)0, info->num_ring_pages * PAGE_SIZE);
>
> /* Stage 1: Make a safe copy of the shadow state. */
> copy = kmalloc(sizeof(info->shadow),
> @@ -1123,13 +1068,13 @@ static int blkif_recover(struct blkfront_info *info)
>
> /* Stage 2: Set up free list. */
> memset(&info->shadow, 0, sizeof(info->shadow));
> - for (i = 0; i < ring_size; i++)
> + for (i = 0; i < BLK_RING_SIZE; i++)
> info->shadow[i].req.u.rw.id = i+1;
> info->shadow_free = info->ring.req_prod_pvt;
> - info->shadow[ring_size-1].req.u.rw.id = 0x0fffffff;
> + info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
>
> /* Stage 3: Find pending requests and requeue them. */
> - for (i = 0; i < ring_size; i++) {
> + for (i = 0; i < BLK_RING_SIZE; i++) {
> /* Not in use? */
> if (!copy[i].request)
> continue;
> @@ -1600,4 +1545,3 @@ MODULE_LICENSE("GPL");
> MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
> MODULE_ALIAS("xen:vbd");
> MODULE_ALIAS("xenblk");
> -
> diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h
> index 31063bd..ee338bf 100644
> --- a/include/xen/interface/io/blkif.h
> +++ b/include/xen/interface/io/blkif.h
> @@ -168,18 +168,6 @@ struct blkif_response {
>
> DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
>
> -/*
> - * Maximum number of pages used for a blkif ring
> - * max-ring-pages advertised by blkback to blkfront may be lowered at blkback
> - * mod load time. Load time param set to default.
> - */
> -#define BLKIF_MAX_NUM_RING_PAGES 16
> -#define BLKIF_MAX_NUM_RING_PAGES_DFLT 4
> -#if BLKIF_MAX_NUM_RING_PAGES < BLKIF_MAX_NUM_RING_PAGES_DFLT
> -#undef BLKIF_MAX_NUM_RING_PAGES_DFLT
> -#define BLKIF_MAX_NUM_RING_PAGES_DFLT BLKIF_MAX_NUM_RING_PAGES
> -#endif
> -
> #define VDISK_CDROM 0x1
> #define VDISK_REMOVABLE 0x2
> #define VDISK_READONLY 0x4
>
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