From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752681AbbKBEWu (ORCPT ); Sun, 1 Nov 2015 23:22:50 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:22475 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752626AbbKBEWp (ORCPT ); Sun, 1 Nov 2015 23:22:45 -0500 From: Bob Liu To: xen-devel@lists.xen.org Cc: linux-kernel@vger.kernel.org, roger.pau@citrix.com, konrad.wilk@oracle.com, felipe.franciosi@citrix.com, axboe@fb.com, avanzini.arianna@gmail.com, rafal.mielniczuk@citrix.com, jonathan.davies@citrix.com, david.vrabel@citrix.com, Bob Liu Subject: [PATCH v4 09/10] xen/blkfront: make persistent grants per-queue Date: Mon, 2 Nov 2015 12:21:45 +0800 Message-Id: <1446438106-20171-10-git-send-email-bob.liu@oracle.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1446438106-20171-1-git-send-email-bob.liu@oracle.com> References: <1446438106-20171-1-git-send-email-bob.liu@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make persistent grants per-queue/ring instead of per-device, so that we can drop the 'dev_lock' and get better scalability. Signed-off-by: Bob Liu --- drivers/block/xen-blkfront.c | 89 +++++++++++++++++--------------------------- 1 file changed, 34 insertions(+), 55 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 23096d7..eb19f08 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -133,6 +133,8 @@ struct blkfront_ring_info { struct gnttab_free_callback callback; struct blk_shadow shadow[BLK_MAX_RING_SIZE]; struct list_head indirect_pages; + struct list_head grants; + unsigned int persistent_gnts_c; unsigned long shadow_free; struct blkfront_info *dev_info; }; @@ -144,8 +146,6 @@ struct blkfront_ring_info { */ struct blkfront_info { - /* Lock to proect info->grants list shared by multi rings */ - spinlock_t dev_lock; struct mutex mutex; struct xenbus_device *xbdev; struct gendisk *gd; @@ -155,8 +155,6 @@ struct blkfront_info /* Number of pages per ring buffer */ unsigned int nr_ring_pages; struct request_queue *rq; - struct list_head grants; - unsigned int persistent_gnts_c; unsigned int feature_flush; unsigned int feature_discard:1; unsigned int feature_secdiscard:1; @@ -231,7 +229,6 @@ static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) struct grant *gnt_list_entry, *n; int i = 0; - spin_lock_irq(&info->dev_lock); while(i < num) { gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO); if (!gnt_list_entry) @@ -247,35 +244,32 @@ static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) } gnt_list_entry->gref = GRANT_INVALID_REF; - list_add(&gnt_list_entry->node, &info->grants); + list_add(&gnt_list_entry->node, &rinfo->grants); i++; } - spin_unlock_irq(&info->dev_lock); return 0; out_of_memory: list_for_each_entry_safe(gnt_list_entry, n, - &info->grants, node) { + &rinfo->grants, node) { list_del(&gnt_list_entry->node); if (info->feature_persistent) __free_page(pfn_to_page(gnt_list_entry->pfn)); kfree(gnt_list_entry); i--; } - spin_unlock_irq(&info->dev_lock); BUG_ON(i != 0); return -ENOMEM; } static struct grant *get_grant(grant_ref_t *gref_head, unsigned long pfn, - struct blkfront_info *info) + struct blkfront_ring_info *info) { struct grant *gnt_list_entry; unsigned long buffer_gfn; - spin_lock(&info->dev_lock); BUG_ON(list_empty(&info->grants)); gnt_list_entry = list_first_entry(&info->grants, struct grant, node); @@ -283,21 +277,19 @@ static struct grant *get_grant(grant_ref_t *gref_head, if (gnt_list_entry->gref != GRANT_INVALID_REF) { info->persistent_gnts_c--; - spin_unlock(&info->dev_lock); return gnt_list_entry; } - spin_unlock(&info->dev_lock); /* Assign a gref to this page */ gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); BUG_ON(gnt_list_entry->gref == -ENOSPC); - if (!info->feature_persistent) { + if (!info->dev_info->feature_persistent) { BUG_ON(!pfn); gnt_list_entry->pfn = pfn; } buffer_gfn = pfn_to_gfn(gnt_list_entry->pfn); gnttab_grant_foreign_access_ref(gnt_list_entry->gref, - info->xbdev->otherend_id, + info->dev_info->xbdev->otherend_id, buffer_gfn, 0); return gnt_list_entry; } @@ -559,13 +551,13 @@ static int blkif_queue_request(struct request *req, struct blkfront_ring_info *r list_del(&indirect_page->lru); pfn = page_to_pfn(indirect_page); } - gnt_list_entry = get_grant(&gref_head, pfn, info); + gnt_list_entry = get_grant(&gref_head, pfn, rinfo); rinfo->shadow[id].indirect_grants[n] = gnt_list_entry; segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn)); ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; } - gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info); + gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), rinfo); ref = gnt_list_entry->gref; rinfo->shadow[id].grants_used[i] = gnt_list_entry; @@ -992,7 +984,7 @@ static void blkif_restart_queue(struct work_struct *work) static void blkif_free_ring(struct blkfront_ring_info *rinfo) { - struct grant *persistent_gnt; + struct grant *persistent_gnt, *n; struct blkfront_info *info = rinfo->dev_info; int i, j, segs; @@ -1010,6 +1002,23 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) } } + /* Remove all persistent grants */ + if (!list_empty(&rinfo->grants)) { + list_for_each_entry_safe(persistent_gnt, n, + &rinfo->grants, node) { + list_del(&persistent_gnt->node); + if (persistent_gnt->gref != GRANT_INVALID_REF) { + gnttab_end_foreign_access(persistent_gnt->gref, + 0, 0UL); + rinfo->persistent_gnts_c--; + } + if (info->feature_persistent) + __free_page(pfn_to_page(persistent_gnt->pfn)); + kfree(persistent_gnt); + } + } + BUG_ON(rinfo->persistent_gnts_c != 0); + for (i = 0; i < BLK_RING_SIZE(info); i++) { /* * Clear persistent grants present in requests already @@ -1075,37 +1084,17 @@ free_shadow: static void blkif_free(struct blkfront_info *info, int suspend) { - struct grant *persistent_gnt, *n; int i; /* Prevent new requests being issued until we fix things up. */ - spin_lock_irq(&info->dev_lock); info->connected = suspend ? BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; /* No more blkif_request(). */ if (info->rq) blk_mq_stop_hw_queues(info->rq); - /* Remove all persistent grants */ - if (!list_empty(&info->grants)) { - list_for_each_entry_safe(persistent_gnt, n, - &info->grants, node) { - list_del(&persistent_gnt->node); - if (persistent_gnt->gref != GRANT_INVALID_REF) { - gnttab_end_foreign_access(persistent_gnt->gref, - 0, 0UL); - info->persistent_gnts_c--; - } - if (info->feature_persistent) - __free_page(pfn_to_page(persistent_gnt->pfn)); - kfree(persistent_gnt); - } - } - BUG_ON(info->persistent_gnts_c != 0); - for (i = 0; i < info->nr_rings; i++) blkif_free_ring(&info->rinfo[i]); - spin_unlock_irq(&info->dev_lock); } static void blkif_completion(struct blk_shadow *s, struct blkfront_ring_info *rinfo, @@ -1117,7 +1106,6 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_ring_info *ri void *shared_data; int nseg; struct blkfront_info *info = rinfo->dev_info; - unsigned long flags; nseg = s->req.operation == BLKIF_OP_INDIRECT ? s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments; @@ -1148,10 +1136,8 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_ring_info *ri if (!info->feature_persistent) pr_alert_ratelimited("backed has not unmapped grant: %u\n", s->grants_used[i]->gref); - spin_lock_irqsave(&info->dev_lock, flags); - list_add(&s->grants_used[i]->node, &info->grants); - info->persistent_gnts_c++; - spin_unlock_irqrestore(&info->dev_lock, flags); + list_add(&s->grants_used[i]->node, &rinfo->grants); + rinfo->persistent_gnts_c++; } else { /* * If the grant is not mapped by the backend we end the @@ -1161,9 +1147,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_ring_info *ri */ gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL); s->grants_used[i]->gref = GRANT_INVALID_REF; - spin_lock_irqsave(&info->dev_lock, flags); - list_add_tail(&s->grants_used[i]->node, &info->grants); - spin_unlock_irqrestore(&info->dev_lock, flags); + list_add_tail(&s->grants_used[i]->node, &rinfo->grants); } } if (s->req.operation == BLKIF_OP_INDIRECT) { @@ -1172,10 +1156,8 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_ring_info *ri if (!info->feature_persistent) pr_alert_ratelimited("backed has not unmapped grant: %u\n", s->indirect_grants[i]->gref); - spin_lock_irqsave(&info->dev_lock, flags); - list_add(&s->indirect_grants[i]->node, &info->grants); - info->persistent_gnts_c++; - spin_unlock_irqrestore(&info->dev_lock, flags); + list_add(&s->indirect_grants[i]->node, &rinfo->grants); + rinfo->persistent_gnts_c++; } else { struct page *indirect_page; @@ -1184,14 +1166,12 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_ring_info *ri * Add the used indirect page back to the list of * available pages for indirect grefs. */ - spin_lock_irqsave(&info->dev_lock, flags); if (!info->feature_persistent) { indirect_page = pfn_to_page(s->indirect_grants[i]->pfn); list_add(&indirect_page->lru, &rinfo->indirect_pages); } s->indirect_grants[i]->gref = GRANT_INVALID_REF; - list_add_tail(&s->indirect_grants[i]->node, &info->grants); - spin_unlock_irqrestore(&info->dev_lock, flags); + list_add_tail(&s->indirect_grants[i]->node, &rinfo->grants); } } } @@ -1587,10 +1567,8 @@ static int blkfront_probe(struct xenbus_device *dev, } mutex_init(&info->mutex); - spin_lock_init(&info->dev_lock); info->xbdev = dev; info->vdevice = vdevice; - INIT_LIST_HEAD(&info->grants); info->connected = BLKIF_STATE_DISCONNECTED; /* Check if backend supports multiple queues */ @@ -1616,6 +1594,7 @@ static int blkfront_probe(struct xenbus_device *dev, struct blkfront_ring_info *rinfo; rinfo = &info->rinfo[r_index]; + INIT_LIST_HEAD(&rinfo->grants); INIT_LIST_HEAD(&rinfo->indirect_pages); rinfo->dev_info = info; INIT_WORK(&rinfo->work, blkif_restart_queue); -- 1.8.3.1