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drivers: xen-blkback: delay pending_req allocation to connect_ring

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This is a pre-patch for multi-page ring feature.
In connect_ring, we can know exactly how many pages are used for the shared
ring, delay pending_req allocation here so that we won't waste too much memory.

Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Bob Liu 2015-06-03 13:40:01 +08:00 committed by Konrad Rzeszutek Wilk
parent a5768aa887
commit 69b91ede5c
2 changed files with 39 additions and 45 deletions
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2
drivers/block/xen-blkback/common.h
View file

@ -248,7 +248,7 @@ struct backend_info;
#define PERSISTENT_GNT_WAS_ACTIVE 1
/* Number of requests that we can fit in a ring */
#define XEN_BLKIF_REQS 32
#define XEN_BLKIF_REQS_PER_PAGE 32
struct persistent_gnt {
struct page *page;

82
drivers/block/xen-blkback/xenbus.c
View file

@ -124,8 +124,6 @@ static void xen_update_blkif_status(struct xen_blkif *blkif)
static struct xen_blkif *xen_blkif_alloc(domid_t domid)
{
struct xen_blkif *blkif;
struct pending_req *req, *n;
int i, j;
BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
@ -151,51 +149,11 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
INIT_LIST_HEAD(&blkif->pending_free);
INIT_WORK(&blkif->free_work, xen_blkif_deferred_free);
for (i = 0; i < XEN_BLKIF_REQS; i++) {
req = kzalloc(sizeof(*req), GFP_KERNEL);
if (!req)
goto fail;
list_add_tail(&req->free_list,
&blkif->pending_free);
for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
req->segments[j] = kzalloc(sizeof(*req->segments[0]),
GFP_KERNEL);
if (!req->segments[j])
goto fail;
}
for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]),
GFP_KERNEL);
if (!req->indirect_pages[j])
goto fail;
}
}
spin_lock_init(&blkif->pending_free_lock);
init_waitqueue_head(&blkif->pending_free_wq);
init_waitqueue_head(&blkif->shutdown_wq);
return blkif;
fail:
list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) {
list_del(&req->free_list);
for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
if (!req->segments[j])
break;
kfree(req->segments[j]);
}
for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
if (!req->indirect_pages[j])
break;
kfree(req->indirect_pages[j]);
}
kfree(req);
}
kmem_cache_free(xen_blkif_cachep, blkif);
return ERR_PTR(-ENOMEM);
}
static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t gref,
@ -312,7 +270,7 @@ static void xen_blkif_free(struct xen_blkif *blkif)
i++;
}
WARN_ON(i != XEN_BLKIF_REQS);
WARN_ON(i != XEN_BLKIF_REQS_PER_PAGE);
kmem_cache_free(xen_blkif_cachep, blkif);
}
@ -864,7 +822,8 @@ static int connect_ring(struct backend_info *be)
unsigned int evtchn;
unsigned int pers_grants;
char protocol[64] = "";
int err;
struct pending_req *req, *n;
int err, i, j;
pr_debug("%s %s\n", __func__, dev->otherend);
@ -905,6 +864,24 @@ static int connect_ring(struct backend_info *be)
ring_ref, evtchn, be->blkif->blk_protocol, protocol,
pers_grants ? "persistent grants" : "");
for (i = 0; i < XEN_BLKIF_REQS_PER_PAGE; i++) {
req = kzalloc(sizeof(*req), GFP_KERNEL);
if (!req)
goto fail;
list_add_tail(&req->free_list, &be->blkif->pending_free);
for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL);
if (!req->segments[j])
goto fail;
}
for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]),
GFP_KERNEL);
if (!req->indirect_pages[j])
goto fail;
}
}
/* Map the shared frame, irq etc. */
err = xen_blkif_map(be->blkif, ring_ref, evtchn);
if (err) {
@ -914,6 +891,23 @@ static int connect_ring(struct backend_info *be)
}
return 0;
fail:
list_for_each_entry_safe(req, n, &be->blkif->pending_free, free_list) {
list_del(&req->free_list);
for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
if (!req->segments[j])
break;
kfree(req->segments[j]);
}
for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
if (!req->indirect_pages[j])
break;
kfree(req->indirect_pages[j]);
}
kfree(req);
}
return -ENOMEM;
}
static const struct xenbus_device_id xen_blkbk_ids[] = {