From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19636C433E1 for ; Fri, 7 Aug 2020 19:35:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECB4B204EC for ; Fri, 7 Aug 2020 19:35:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nEnfdelS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726466AbgHGTfW (ORCPT ); Fri, 7 Aug 2020 15:35:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726038AbgHGTfW (ORCPT ); Fri, 7 Aug 2020 15:35:22 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38E5CC061756 for ; Fri, 7 Aug 2020 12:35:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=t2izdhy9urvECJgu7c0L+DP8+hLwhvJe9LrSJI1uUoU=; b=nEnfdelSe1G9Q+nx+YpNh0mw1/ +a4gGLD0aa9HwBzJxEjQA3qi4g3PXKSq79Y2zY7r0uTtXUyt2tr8itdma+mPNnJjLysKop3luLRvG +s7fjtFyK5BDV4QlN7hM/nOamL+SwvA0z5nuEEDEVkjWFjr9iEPhOAGmNcZDkABfyKoAlFsgnfKBI dcflAoOAEb0LQ5wMksJBIOfeRdBCdYEXiElhQbz8I5flB4ii8eeyt7t8c0xOeXGXxXRhYURPthiAf RSriqo9p5uWoZquYNMFKQWc4plLasbaF3PUqWR6M8S7fAD6PS3GH5YwF8HMfn+hn0rAXP3VhMVAj3 wjY/kmAg==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1k4890-0001tN-N2; Fri, 07 Aug 2020 19:35:10 +0000 Date: Fri, 7 Aug 2020 20:35:10 +0100 From: Matthew Wilcox To: Hugh Dickins Cc: Linus Torvalds , Oleg Nesterov , Michal Hocko , Linux-MM , LKML , Andrew Morton , Tim Chen , Michal Hocko , Greg KH Subject: Re: [RFC PATCH] mm: silence soft lockups from unlock_page Message-ID: <20200807193510.GG17456@casper.infradead.org> References: <20200725101445.GB3870@redhat.com> <20200806180024.GB17456@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 07, 2020 at 11:41:09AM -0700, Hugh Dickins wrote: > My home testing was, effectively, on top of c6fe44d96fc1 (v5.8 plus > your two patches): I did not have in the io_uring changes from the > current tree. In glancing there, I noticed one new and one previous > instance of SetPageWaiters() *after* __add_wait_queue_entry_tail(): > are those correct? By the way, don't do any performance testing on current Linus tree. This commit: commit 37f4a24c2469a10a4c16c641671bd766e276cf9f (refs/bisect/bad) Author: Ming Lei Date: Tue Jun 30 22:03:57 2020 +0800 blk-mq: centralise related handling into blk_mq_get_driver_tag Move .nr_active update and request assignment into blk_mq_get_driver_tag(), all are good to do during getting driver tag. Meantime blk-flush related code is simplified and flush request needn't to update the request table manually any more. Signed-off-by: Ming Lei Cc: Christoph Hellwig Signed-off-by: Jens Axboe slows everything down, at least on my test qemu system. Seems like it's losing block queue tags.