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 6E88FC67871 for ; Mon, 24 Oct 2022 22:20:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231194AbiJXWUS (ORCPT ); Mon, 24 Oct 2022 18:20:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231207AbiJXWTt (ORCPT ); Mon, 24 Oct 2022 18:19:49 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93A2B16A4EB for ; Mon, 24 Oct 2022 13:37:23 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D5C2A6158B for ; Mon, 24 Oct 2022 20:35:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BBBCC433C1; Mon, 24 Oct 2022 20:35:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1666643745; bh=GSlAQPTsKUwZ/UQo7K1x1PriPC/cwU0XHwG9jwZID/4=; h=Date:To:From:Subject:From; b=TqFAekHCaQwqRwSE8fFxAiw6N3SuuFKx/gT8tCBKbx5psxJoik4C3CLoDneqmAIm7 FqlCtOzfh3gYPHLpiwywMYy9yKz9Rb4grN1Z+WxGGkrJco6gbGmXxAagUrFz7vE4y+ pE2x1LcM0SRB5VphHA6dSVkKcvEumdV9rA34D3oA= Date: Mon, 24 Oct 2022 13:35:44 -0700 To: mm-commits@vger.kernel.org, ngupta@vflare.org, minchan@kernel.org, senozhatsky@chromium.org, akpm@linux-foundation.org From: Andrew Morton Subject: + zsmalloc-make-sure-we-select-best-zspage-size.patch added to mm-unstable branch Message-Id: <20221024203545.3BBBCC433C1@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: zsmalloc: make sure we select best zspage size has been added to the -mm mm-unstable branch. Its filename is zsmalloc-make-sure-we-select-best-zspage-size.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zsmalloc-make-sure-we-select-best-zspage-size.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Sergey Senozhatsky Subject: zsmalloc: make sure we select best zspage size Date: Tue, 25 Oct 2022 01:12:13 +0900 We currently decide the best zspage size by looking at used percentage value. This is not exactly enough as zspage usage percentage calculation is not accurate. For example, let's look at size class 208 pages per zspage wasted bytes used% 1 144 96 2 80 99 3 16 99 4 160 99 We will select 2 page per zspage configuration, as it is the first one to reach 99%. However, 3 pages per zspage wastes less memory. Hence we need to also consider wasted space metrics when device zspage size. Additionally, rename max_usedpc_order because it does not hold zspage order, it holds maximum pages per-zspage value. Link: https://lkml.kernel.org/r/20221024161213.3221725-7-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky Cc: Minchan Kim Cc: Nitin Gupta Signed-off-by: Andrew Morton --- mm/zsmalloc.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) --- a/mm/zsmalloc.c~zsmalloc-make-sure-we-select-best-zspage-size +++ a/mm/zsmalloc.c @@ -775,8 +775,9 @@ out: static int get_pages_per_zspage(struct zs_pool *pool, int class_size) { int i, max_usedpc = 0; - /* zspage order which gives maximum used size per KB */ - int max_usedpc_order = 1; + /* zspage size which gives maximum used size per KB */ + int pages_per_zspage = 1; + int min_waste = INT_MAX; for (i = 1; i <= pool->max_pages_per_zspage; i++) { int zspage_size; @@ -788,14 +789,19 @@ static int get_pages_per_zspage(struct z if (usedpc > max_usedpc) { max_usedpc = usedpc; - max_usedpc_order = i; + pages_per_zspage = i; } if (usedpc == 100) break; + + if (waste < min_waste) { + min_waste = waste; + pages_per_zspage = i; + } } - return max_usedpc_order; + return pages_per_zspage; } static struct zspage *get_zspage(struct page *page) _ Patches currently in -mm which might be from senozhatsky@chromium.org are zram-preparation-for-multi-zcomp-support.patch zram-add-recompression-algorithm-sysfs-knob.patch zram-factor-out-wb-and-non-wb-zram-read-functions.patch zram-introduce-recompress-sysfs-knob.patch documentation-add-recompression-documentation.patch zram-add-recompression-algorithm-choice-to-kconfig.patch zram-add-recompress-flag-to-read_block_state.patch zram-clarify-writeback_store-comment.patch zram-use-is_err_value-to-check-for-zs_malloc-errors.patch zsmalloc-turn-zspage-order-into-runtime-variable.patch zsmalloc-zram-pass-zspage-order-to-zs_create_pool.patch zram-add-pool_page_order-device-attribute.patch documentation-document-zram-pool_page_order-attribute.patch zsmalloc-break-out-of-loop-when-found-perfect-zspage-order.patch zsmalloc-make-sure-we-select-best-zspage-size.patch