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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 60ECFC4360F for ; Thu, 14 Mar 2019 20:38:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2343F2186A for ; Thu, 14 Mar 2019 20:38:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=tobin.cc header.i=@tobin.cc header.b="C4t2ZAcr"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="C8flOQXS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727896AbfCNUil (ORCPT ); Thu, 14 Mar 2019 16:38:41 -0400 Received: from out2-smtp.messagingengine.com ([66.111.4.26]:59765 "EHLO out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727774AbfCNUik (ORCPT ); Thu, 14 Mar 2019 16:38:40 -0400 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id C02F821347; Thu, 14 Mar 2019 16:38:39 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute5.internal (MEProxy); Thu, 14 Mar 2019 16:38:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tobin.cc; h=date :from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=fm2; bh=4W86yzgBmI60fQ5wjGxGK8pZF6Q ZHKew4cQhSuRbaSg=; b=C4t2ZAcrxhJUM8MAPqV4iBkYgDjl2glRTV2OfcHZi01 Rdn3fhaaIbeh9vntPVx/HMxx6MtS4MzuDpJ6WxVhSBraCDjbMfKnNI1jTUHww+MK jAnpsV2AoEtwoiVZgCPKz5iIyfHBifFZrZ3JHCaNUpjxfqBOo/epfcD0kxChCBMh O+Jv91MF1oJzB9lBgzTdeAW7yZJz6+dkacI+li54ijCVXiNfeCrnbRHaWn87VimY fPNA7qOHQu3cR/Zh/WJIdK87QfzCitUtWckzyRK7ZhRh62Y7BIyXt2hAaiLSkX3p Ww23qIqX4Wkg3B3q/YZaOYLcW89PDNihLhwE56VO4jA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=4W86yz gBmI60fQ5wjGxGK8pZF6QZHKew4cQhSuRbaSg=; b=C8flOQXS4ObL5z8WR4MY/V /1dtvsvGY8qdzXytlrj0N08J3xXS+QYtbU3H9l3A09tNLh9YhF0ENWQV4MuRs7pu G/vG09wzdZAcJZJLAnmp7DQ37W2UpXoJI3Zu7TZkqbj/SNw7xU07t3DCsBCFgy12 LXMa6T9umfGv/PdAVg02dPtTR76CTVolmp7KFPOsJuHPgoYfZbkaNYpU9E9Vn/uI ehHF+uZUY8rXl/Z2qPIhXQuKUMbHTJKwdYTcY1LHa/z2mTCoxuoOzdK8E3xalKV+ 4epmbZG9lTWnIha+GjeBDDCq/d6MWXZNIVobT5I+h04O2+xVBWrqHxCngMgik8eg == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedutddrheefgdegkecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenfg hrlhcuvffnffculddutddmnecujfgurhepfffhvffukfhfgggtuggjofgfsehttdertdfo redvnecuhfhrohhmpedfvfhosghinhcuvedrucfjrghrughinhhgfdcuoehmvgesthhosg hinhdrtggtqeenucfkphepuddvgedrudeiledrvdefrddukeegnecurfgrrhgrmhepmhgr ihhlfhhrohhmpehmvgesthhosghinhdrtggtnecuvehluhhsthgvrhfuihiivgeptd X-ME-Proxy: Received: from localhost (124-169-23-184.dyn.iinet.net.au [124.169.23.184]) by mail.messagingengine.com (Postfix) with ESMTPA id ADBFDE455C; Thu, 14 Mar 2019 16:38:35 -0400 (EDT) Date: Fri, 15 Mar 2019 07:38:09 +1100 From: "Tobin C. Harding" To: Roman Gushchin Cc: "Tobin C. Harding" , Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Matthew Wilcox , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v3 3/7] slob: Use slab_list instead of lru Message-ID: <20190314203809.GA22506@eros.localdomain> References: <20190314053135.1541-1-tobin@kernel.org> <20190314053135.1541-4-tobin@kernel.org> <20190314185219.GA6441@tower.DHCP.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190314185219.GA6441@tower.DHCP.thefacebook.com> X-Mailer: Mutt 1.11.3 (2019-02-01) User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 14, 2019 at 06:52:25PM +0000, Roman Gushchin wrote: > On Thu, Mar 14, 2019 at 04:31:31PM +1100, Tobin C. Harding wrote: > > Currently we use the page->lru list for maintaining lists of slabs. We > > have a list_head in the page structure (slab_list) that can be used for > > this purpose. Doing so makes the code cleaner since we are not > > overloading the lru list. > > > > The slab_list is part of a union within the page struct (included here > > stripped down): > > > > union { > > struct { /* Page cache and anonymous pages */ > > struct list_head lru; > > ... > > }; > > struct { > > dma_addr_t dma_addr; > > }; > > struct { /* slab, slob and slub */ > > union { > > struct list_head slab_list; > > struct { /* Partial pages */ > > struct page *next; > > int pages; /* Nr of pages left */ > > int pobjects; /* Approximate count */ > > }; > > }; > > ... > > > > Here we see that slab_list and lru are the same bits. We can verify > > that this change is safe to do by examining the object file produced from > > slob.c before and after this patch is applied. > > > > Steps taken to verify: > > > > 1. checkout current tip of Linus' tree > > > > commit a667cb7a94d4 ("Merge branch 'akpm' (patches from Andrew)") > > > > 2. configure and build (select SLOB allocator) > > > > CONFIG_SLOB=y > > CONFIG_SLAB_MERGE_DEFAULT=y > > > > 3. dissasemble object file `objdump -dr mm/slub.o > before.s > > 4. apply patch > > 5. build > > 6. dissasemble object file `objdump -dr mm/slub.o > after.s > > 7. diff before.s after.s > > > > Use slab_list list_head instead of the lru list_head for maintaining > > lists of slabs. > > > > Reviewed-by: Roman Gushchin > > Signed-off-by: Tobin C. Harding > > --- > > mm/slob.c | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/mm/slob.c b/mm/slob.c > > index 39ad9217ffea..94486c32e0ff 100644 > > --- a/mm/slob.c > > +++ b/mm/slob.c > > @@ -112,13 +112,13 @@ static inline int slob_page_free(struct page *sp) > > > > static void set_slob_page_free(struct page *sp, struct list_head *list) > > { > > - list_add(&sp->lru, list); > > + list_add(&sp->slab_list, list); > > __SetPageSlobFree(sp); > > } > > > > static inline void clear_slob_page_free(struct page *sp) > > { > > - list_del(&sp->lru); > > + list_del(&sp->slab_list); > > __ClearPageSlobFree(sp); > > } > > > > @@ -282,7 +282,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node) > > > > spin_lock_irqsave(&slob_lock, flags); > > /* Iterate through each partially free page, try to find room */ > > - list_for_each_entry(sp, slob_list, lru) { > > + list_for_each_entry(sp, slob_list, slab_list) { > > #ifdef CONFIG_NUMA > > /* > > * If there's a node specification, search for a partial > > > Hi Tobin! > > How about list_rotate_to_front(&next->lru, slob_list) from the previous patch? > Shouldn't it use slab_list instead of lru too? Thanks Roman, my mistake - one too many rebases. I hate when I drop the ball like this. Tobin.