From: Dmitry Bogdanov Date: Tue, 14 Sep 2021 10:55:39 +0000 (+0300) Subject: scsi: efct: Decrease area under spinlock X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e76b7c5e25a1fa818bb3e727873a899cc89f5196;p=linux.git scsi: efct: Decrease area under spinlock Under the session level spinlock node->active_ios_lock in efct_scsi_io_alloc() we are taking another spinlock for the port. This leads to contention between sessions and even between I/Os in the same session. Reduce the locked region to active_ios list for which active_ios_lock is intended. Spinlock CPU usage decreases from 18% down to 13%. IOPS are increased from 220 kIOPS to 264 kIOPS for one LUN. Link: https://lore.kernel.org/r/20210914105539.6942-4-d.bogdanov@yadro.com Reviewed-by: Roman Bolshakov Reviewed-by: Ram Vegesna Signed-off-by: Dmitry Bogdanov Signed-off-by: Martin K. Petersen --- diff --git a/drivers/scsi/elx/efct/efct_scsi.c b/drivers/scsi/elx/efct/efct_scsi.c index 40fb3a724c76d..8535bb7eabd8e 100644 --- a/drivers/scsi/elx/efct/efct_scsi.c +++ b/drivers/scsi/elx/efct/efct_scsi.c @@ -38,8 +38,6 @@ efct_scsi_io_alloc(struct efct_node *node) xport = efct->xport; - spin_lock_irqsave(&node->active_ios_lock, flags); - io = efct_io_pool_io_alloc(efct->xport->io_pool); if (!io) { efc_log_err(efct, "IO alloc Failed\n"); @@ -66,6 +64,7 @@ efct_scsi_io_alloc(struct efct_node *node) /* Add to node's active_ios list */ INIT_LIST_HEAD(&io->list_entry); + spin_lock_irqsave(&node->active_ios_lock, flags); list_add(&io->list_entry, &node->active_ios); spin_unlock_irqrestore(&node->active_ios_lock, flags);