From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:41994 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751023AbdJSNN1 (ORCPT ); Thu, 19 Oct 2017 09:13:27 -0400 Subject: Patch "vmbus: more host signalling avoidance" has been added to the 4.13-stable tree To: stephen@networkplumber.org, gregkh@linuxfoundation.org, kys@microsoft.com, sthemmin@microsoft.com Cc: , From: Date: Thu, 19 Oct 2017 15:13:32 +0200 Message-ID: <1508418812127233@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled vmbus: more host signalling avoidance to the 4.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: vmbus-more-host-signalling-avoidance.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 03bad714a1619c0074eb44d6f217c505fe27030f Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Sun, 25 Jun 2017 12:30:28 -0700 Subject: vmbus: more host signalling avoidance From: Stephen Hemminger commit 03bad714a1619c0074eb44d6f217c505fe27030f upstream. Don't signal host if it has disabled interrupts for that ring buffer. Check the feature bit to see if host supports pending send size flag. Signed-off-by: Stephen Hemminger Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/ring_buffer.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -396,7 +396,6 @@ void hv_pkt_iter_close(struct vmbus_chan { struct hv_ring_buffer_info *rbi = &channel->inbound; u32 orig_write_sz = hv_get_bytes_to_write(rbi); - u32 pending_sz; /* * Make sure all reads are done before we update the read index since @@ -419,15 +418,27 @@ void hv_pkt_iter_close(struct vmbus_chan */ virt_mb(); - pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz); - /* If the other end is not blocked on write don't bother. */ - if (pending_sz == 0) + /* If host has disabled notifications then skip */ + if (rbi->ring_buffer->interrupt_mask) return; - if (hv_get_bytes_to_write(rbi) < pending_sz) - return; + if (rbi->ring_buffer->feature_bits.feat_pending_send_sz) { + u32 pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz); + + /* + * If there was space before we began iteration, + * then host was not blocked. Also handles case where + * pending_sz is zero then host has nothing pending + * and does not need to be signaled. + */ + if (orig_write_sz > pending_sz) + return; + + /* If pending write will not fit, don't give false hope. */ + if (hv_get_bytes_to_write(rbi) < pending_sz) + return; + } - if (orig_write_sz < pending_sz) - vmbus_setevent(channel); + vmbus_setevent(channel); } EXPORT_SYMBOL_GPL(hv_pkt_iter_close); Patches currently in stable-queue which might be from stephen@networkplumber.org are queue-4.13/vmbus-more-host-signalling-avoidance.patch queue-4.13/vmbus-refactor-hv_signal_on_read.patch queue-4.13/vmbus-simplify-hv_ringbuffer_read.patch queue-4.13/vmbus-eliminate-duplicate-cached-index.patch