Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753512AbaATVZ3 (ORCPT ); Mon, 20 Jan 2014 16:25:29 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:45710 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752864AbaATVZC (ORCPT ); Mon, 20 Jan 2014 16:25:02 -0500 X-IronPort-AV: E=Sophos;i="4.95,692,1384300800"; d="scan'208";a="92595855" From: Zoltan Kiss To: , , , , , CC: Zoltan Kiss Subject: [PATCH net-next v5 9/9] xen-netback: Aggregate TX unmap operations Date: Mon, 20 Jan 2014 21:24:29 +0000 Message-ID: <1390253069-25507-10-git-send-email-zoltan.kiss@citrix.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1390253069-25507-1-git-send-email-zoltan.kiss@citrix.com> References: <1390253069-25507-1-git-send-email-zoltan.kiss@citrix.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.80.2.133] X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Unmapping causes TLB flushing, therefore we should make it in the largest possible batches. However we shouldn't starve the guest for too long. So if the guest has space for at least two big packets and we don't have at least a quarter ring to unmap, delay it for at most 1 milisec. v4: - use bool for tx_dealloc_work_todo Signed-off-by: Zoltan Kiss --- drivers/net/xen-netback/common.h | 2 ++ drivers/net/xen-netback/interface.c | 2 ++ drivers/net/xen-netback/netback.c | 34 +++++++++++++++++++++++++++++++++- 3 files changed, 37 insertions(+), 1 deletion(-) diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h index d1cd8ce..95498c8 100644 --- a/drivers/net/xen-netback/common.h +++ b/drivers/net/xen-netback/common.h @@ -118,6 +118,8 @@ struct xenvif { u16 dealloc_ring[MAX_PENDING_REQS]; struct task_struct *dealloc_task; wait_queue_head_t dealloc_wq; + struct timer_list dealloc_delay; + bool dealloc_delay_timed_out; /* Use kthread for guest RX */ struct task_struct *task; diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 40aa500..f925af5 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -407,6 +407,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid, .desc = i }; vif->grant_tx_handle[i] = NETBACK_INVALID_HANDLE; } + init_timer(&vif->dealloc_delay); /* * Initialise a dummy MAC address. We choose the numerically @@ -557,6 +558,7 @@ void xenvif_disconnect(struct xenvif *vif) } if (vif->dealloc_task) { + del_timer_sync(&vif->dealloc_delay); kthread_stop(vif->dealloc_task); vif->dealloc_task = NULL; } diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index bb65c7c..c098276 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -135,6 +135,11 @@ static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif) vif->pending_prod + vif->pending_cons; } +static inline pending_ring_idx_t nr_free_slots(struct xen_netif_tx_back_ring *ring) +{ + return ring->nr_ents - (ring->sring->req_prod - ring->rsp_prod_pvt); +} + bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed) { RING_IDX prod, cons; @@ -1932,9 +1937,36 @@ static inline int tx_work_todo(struct xenvif *vif) return 0; } +static void xenvif_dealloc_delay(unsigned long data) +{ + struct xenvif *vif = (struct xenvif *)data; + + vif->dealloc_delay_timed_out = true; + wake_up(&vif->dealloc_wq); +} + static inline bool tx_dealloc_work_todo(struct xenvif *vif) { - return vif->dealloc_cons != vif->dealloc_prod + if (vif->dealloc_cons != vif->dealloc_prod) { + if ((nr_free_slots(&vif->tx) > 2 * XEN_NETBK_LEGACY_SLOTS_MAX) && + (vif->dealloc_prod - vif->dealloc_cons < MAX_PENDING_REQS / 4) && + !vif->dealloc_delay_timed_out) { + if (!timer_pending(&vif->dealloc_delay)) { + vif->dealloc_delay.function = + xenvif_dealloc_delay; + vif->dealloc_delay.data = (unsigned long)vif; + mod_timer(&vif->dealloc_delay, + jiffies + msecs_to_jiffies(1)); + + } + return false; + } + del_timer_sync(&vif->dealloc_delay); + vif->dealloc_delay_timed_out = false; + return true; + } + + return false; } void xenvif_unmap_frontend_rings(struct xenvif *vif) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/