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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85A94C433FE for ; Wed, 2 Nov 2022 04:14:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229684AbiKBEOK (ORCPT ); Wed, 2 Nov 2022 00:14:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229523AbiKBEOH (ORCPT ); Wed, 2 Nov 2022 00:14:07 -0400 Received: from mail-pg1-x533.google.com (mail-pg1-x533.google.com [IPv6:2607:f8b0:4864:20::533]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCE0223146 for ; Tue, 1 Nov 2022 21:14:03 -0700 (PDT) Received: by mail-pg1-x533.google.com with SMTP id h193so6504214pgc.10 for ; Tue, 01 Nov 2022 21:14:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=c30GhC3CoSosVopfRUjx7dVhkmM5E32hTKQ81gMJsz8=; b=CMdN+AncmaG8HzjUzD9ywczQaU/TKgxywNgXU/V1Ac3MzLcrIYrGtAEky0EN0t9Z+R kziHTMp/GxnodGxxW8GiqtstZ2gv4PQpowivv1e7YIieaYETHVrvPK18tNiO122bulaI EXqiS6Flg0fa12XxofyPl6OT+HjtsLwAn0iLo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=c30GhC3CoSosVopfRUjx7dVhkmM5E32hTKQ81gMJsz8=; b=NNsMZ8Y4y4n8rFKBlcaLE4NnG2DeBbrEzihO5qSwGfR4+ABDb62DozYl+AHlFx1l77 6vKuhxI9ziTMdiSPHaC0IE24+FtLff3fjxXpwRHKHap/4dwJjOq338VWwUDu6tNpGOsP bKnf9V0vk24f4UlMBwWkEVptA/BTd3A2NOw2S0E+NNVrO36TcCVu9DVa4d2soa8pzcWN f29+hHLA3LZK7MoVU6XmE3MyC8sx0+M/bxj5gagzsqvtmMzeklCs0PTlUca4zlw7QG8Q ZuWyMCcEnfGNFwBZUeNlegc5ne/Xx8rZ2PHXwbkcSRh5pYBy+092sKsHCQiOQAODVY26 EC+Q== X-Gm-Message-State: ACrzQf3vyHmTJW0k3d3oDKoa1kTh8sry9DOIm4voeEBomHYkH/2WxerZ z9G725F9/hnHQHKUP+E7tc0dmg== X-Google-Smtp-Source: AMsMyM6oSQXsw+x4LT1N+XG0H91Ng+MhsL+HQJ99odIHJfJ9qXaMBWV8NxtN5U8+WL9yAk+X7o0AMQ== X-Received: by 2002:a63:d211:0:b0:46f:6229:c380 with SMTP id a17-20020a63d211000000b0046f6229c380mr19785356pgg.621.1667362443346; Tue, 01 Nov 2022 21:14:03 -0700 (PDT) Received: from google.com ([240f:75:7537:3187:f558:dfb0:7cb7:44d9]) by smtp.gmail.com with ESMTPSA id l6-20020a170903244600b00187197c499asm5386872pls.164.2022.11.01.21.14.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Nov 2022 21:14:02 -0700 (PDT) Date: Wed, 2 Nov 2022 13:13:58 +0900 From: Sergey Senozhatsky To: Nhat Pham Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, minchan@kernel.org, ngupta@vflare.org, senozhatsky@chromium.org, sjenning@redhat.com, ddstreet@ieee.org, vitaly.wool@konsulko.com Subject: Re: [PATCH v2 5/5] zsmalloc: Implement writeback mechanism for zsmalloc Message-ID: References: <202210272158.7swYwd23-lkp@intel.com> <20221027182736.513530-1-nphamcs@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221027182736.513530-1-nphamcs@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (22/10/27 11:27), Nhat Pham wrote: > + > +static int zs_zpool_shrink(void *pool, unsigned int pages, > + unsigned int *reclaimed) > +{ > + unsigned int total = 0; > + int ret = -EINVAL; > + > + while (total < pages) { > + ret = zs_reclaim_page(pool, 8); > + if (ret < 0) > + break; > + total++; > + } > + > + if (reclaimed) > + *reclaimed = total; > + > + return ret; > +} The name collides with shrinker callbacks (compaction). That's a bit confusing, took me some time. > @@ -482,6 +504,7 @@ static struct zpool_driver zs_zpool_driver = { > .malloc_support_movable = true, > .malloc = zs_zpool_malloc, > .free = zs_zpool_free, > + .shrink = zs_zpool_shrink, > .map = zs_zpool_map, > .unmap = zs_zpool_unmap, > .total_size = zs_zpool_total_size, > @@ -955,6 +978,21 @@ static int trylock_zspage(struct zspage *zspage) > return 0; > } [..] > +#ifdef CONFIG_ZPOOL > +static int zs_reclaim_page(struct zs_pool *pool, unsigned int retries) > +{ > + int i, obj_idx, ret = 0; > + unsigned long handle; > + struct zspage *zspage; > + struct page *page; > + enum fullness_group fullness; > + > + /* Lock LRU and fullness list */ > + spin_lock(&pool->lock); > + if (!pool->ops || !pool->ops->evict || list_empty(&pool->lru) || You don't need pool->lock for pool->ops/pool->ops->evict checks. But, more importantly, I don't understand why is it even checked here? Why do we use ops->evict? Why cannot we call into zsmalloc evict directly? All of these are statically defined in zsmalloc, just don't provide .shrink if !define CONFIG_ZPOOL? Under what circumstances zsmalloc can provide .shrink but no ->evict?