From 85d9abcd7331566781b93ff46e4bccd4806ef2b2 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 11 Mar 2022 11:35:27 +0100 Subject: xen/blkfront: speed up purge_persistent_grants() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit purge_persistent_grants() is scanning the grants list for persistent grants being no longer in use by the backend. When having found such a grant, it will be set to "invalid" and pushed to the tail of the list. Instead of pushing it directly to the end of the list, add it first to a temporary list, avoiding to scan those entries again in the main list traversal. After having finished the scan, append the temporary list to the grant list. Suggested-by: Jan Beulich Signed-off-by: Juergen Gross Reviewed-by: Roger Pau Monné Reviewed-by: Jan Beulich Link: https://lore.kernel.org/r/20220311103527.12931-1-jgross@suse.com Signed-off-by: Jens Axboe --- drivers/block/xen-blkfront.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/block/xen-blkfront.c') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index ccd0dd0c6b83..5d04e480f36a 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -2521,6 +2521,7 @@ static void purge_persistent_grants(struct blkfront_info *info) for_each_rinfo(info, rinfo, i) { struct grant *gnt_list_entry, *tmp; + LIST_HEAD(grants); spin_lock_irqsave(&rinfo->ring_lock, flags); @@ -2539,9 +2540,11 @@ static void purge_persistent_grants(struct blkfront_info *info) gnttab_end_foreign_access(gnt_list_entry->gref, 0, 0UL); rinfo->persistent_gnts_c--; gnt_list_entry->gref = GRANT_INVALID_REF; - list_add_tail(&gnt_list_entry->node, &rinfo->grants); + list_add_tail(&gnt_list_entry->node, &grants); } + list_splice_tail(&grants, &rinfo->grants); + spin_unlock_irqrestore(&rinfo->ring_lock, flags); } } -- cgit v1.2.3