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 63C7FECAAD8 for ; Thu, 15 Sep 2022 01:57:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229893AbiIOB5u (ORCPT ); Wed, 14 Sep 2022 21:57:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49212 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230091AbiIOB5p (ORCPT ); Wed, 14 Sep 2022 21:57:45 -0400 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF6568E4F5 for ; Wed, 14 Sep 2022 18:57:41 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046051;MF=xhao@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0VPqW6wP_1663207057; Received: from 30.240.97.215(mailfrom:xhao@linux.alibaba.com fp:SMTPD_---0VPqW6wP_1663207057) by smtp.aliyun-inc.com; Thu, 15 Sep 2022 09:57:38 +0800 Message-ID: Date: Thu, 15 Sep 2022 09:57:37 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.2.1 Subject: Re: [PATCH V2] mm/damon: simplify scheme create in lru_sort.c To: SeongJae Park Cc: akpm@linux-foundation.org, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20220914142250.1269-1-sj@kernel.org> From: haoxin In-Reply-To: <20220914142250.1269-1-sj@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/9/14 下午10:22, SeongJae Park 写道: > Hi Xin, > > On Wed, 14 Sep 2022 19:38:59 +0800 Xin Hao wrote: > >> In damon_lru_sort_new_hot_scheme() and damon_lru_sort_new_cold_scheme(), >> they have so much in common, so we can combine them into a single >> function, and we just need to distinguish their differences. > Thank you again for patiently waiting for my changes and reworking on this! > >> Signed-off-by: Xin Hao >> --- >> mm/damon/lru_sort.c | 57 ++++++++++++++++++++++----------------------- >> 1 file changed, 28 insertions(+), 29 deletions(-) >> >> diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c >> index 07a0908963fd..2eac907e866d 100644 >> --- a/mm/damon/lru_sort.c >> +++ b/mm/damon/lru_sort.c >> @@ -135,17 +135,40 @@ DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_cold_stat, >> static struct damon_ctx *ctx; >> static struct damon_target *target; >> >> -static struct damos *damon_lru_sort_new_scheme( >> - struct damos_access_pattern *pattern, enum damos_action action) >> +static struct damos *damon_lru_sort_new_scheme(unsigned int thres, >> + enum damos_action action) >> { >> + struct damos_access_pattern pattern = { >> + /* Find regions having PAGE_SIZE or larger size */ >> + .min_sz_region = PAGE_SIZE, >> + .max_sz_region = ULONG_MAX, >> + /* and accessed for more than the threshold */ > This comment would be better to be written again? > >> + .min_nr_accesses = 0, >> + .max_nr_accesses = 0, > If we're gonna set above two fields anyway later, we could simply remove above > three lines. > >> + /* no matter its age */ >> + .min_age_region = 0, >> + .max_age_region = UINT_MAX, >> + }; >> struct damos_quota quota = damon_lru_sort_quota; >> >> /* Use half of total quota for hot/cold pages sorting */ >> quota.ms = quota.ms / 2; >> >> + switch (action) { >> + case DAMOS_LRU_PRIO: >> + pattern.min_nr_accesses = thres; >> + pattern.max_nr_accesses = UINT_MAX; >> + break; >> + case DAMOS_LRU_DEPRIO: >> + pattern.min_age_region = thres; >> + break; >> + default: >> + return NULL; >> + } >> + > This switch-case makes me wondering if the 'default' case really possible case. > I think it would be clearer to set these from caller. > > IMHO, it might be clearer and shorter to define a static global 'struct > damos_access_pattern' stub variable, and make the > damon_lru_sort_new_{hot,cold}_scheme() copies it to their local variable, > update the relevant fields, and pass that to 'damon_new_scheme()'. What do you > think? > >> return damon_new_scheme( >> /* find the pattern, and */ >> - pattern, >> + &pattern, >> /* (de)prioritize on LRU-lists */ >> action, >> /* under the quota. */ >> @@ -157,37 +180,13 @@ static struct damos *damon_lru_sort_new_scheme( >> /* Create a DAMON-based operation scheme for hot memory regions */ >> static struct damos *damon_lru_sort_new_hot_scheme(unsigned int hot_thres) >> { >> - struct damos_access_pattern pattern = { >> - /* Find regions having PAGE_SIZE or larger size */ >> - .min_sz_region = PAGE_SIZE, >> - .max_sz_region = ULONG_MAX, >> - /* and accessed for more than the threshold */ >> - .min_nr_accesses = hot_thres, >> - .max_nr_accesses = UINT_MAX, >> - /* no matter its age */ >> - .min_age_region = 0, >> - .max_age_region = UINT_MAX, >> - }; >> - >> - return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_PRIO); >> + return damon_lru_sort_new_scheme(hot_thres, DAMOS_LRU_PRIO); > If we follow what I suggested above, we could make this like below: > > struct damos_access_pattern pattern = damon_lru_sort_stub_access_pattern; > > pattern.min_nr_accesses = hot_thres; > return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_PRIO); Agree totally,  i will fix it in the next patch. >> } >> >> /* Create a DAMON-based operation scheme for cold memory regions */ >> static struct damos *damon_lru_sort_new_cold_scheme(unsigned int cold_thres) >> { >> - struct damos_access_pattern pattern = { >> - /* Find regions having PAGE_SIZE or larger size */ >> - .min_sz_region = PAGE_SIZE, >> - .max_sz_region = ULONG_MAX, >> - /* and not accessed at all */ >> - .min_nr_accesses = 0, >> - .max_nr_accesses = 0, >> - /* for min_age or more micro-seconds */ >> - .min_age_region = cold_thres, >> - .max_age_region = UINT_MAX, >> - }; >> - >> - return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_DEPRIO); >> + return damon_lru_sort_new_scheme(cold_thres, DAMOS_LRU_DEPRIO); > And similarly here. > >> } >> >> static int damon_lru_sort_apply_parameters(void) >> -- >> 2.31.0 >> >> > > Thanks, > SJ