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h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=QyA2j5YWnnHSq+E6+k1LtPGM4F7JMOWL5Umjq8NWOZU=; b=KeVg5VV5bmknHQ8NRiy2XeLeS6sFQVFdpIdSwTNY8EIkMYILNSnhfzmC0DPFwJymL1 yYTMx34FWpsKesHLVH6C3Ll/amiVzS8js8cKx9zuhlC1APyzenLwrY+a82m4pJIxin+l LqsBsWPhyOr/tGhtZcWmWm4QctYsbN7uY4nUGVK2Y1NIWL95GZR7r/fpX2LeU8/jnd+Z cm6cy2rhinrhgTboyEN14+5LQYEfcyT7LIdi8j90/A1FfwX8e65Hq+8PUtw0/h+hOofg PpZtyQ7dsnWz9IS8PV+taLRaOP/yeNOOzdalzhjVhQZ1jjqI8uNH52GhLIggP2L1IatU FCzg== X-Gm-Message-State: AOAM533eNX/eq86sSQzFkQeiaaR77YYaOvW8rymCBK/JVF1J6S2kD+vn PQqIOQPGDEHvM3FhNmbuSMTbBSNroDAvX0pNA/chvQ== X-Google-Smtp-Source: ABdhPJxHD3BYt5S/qVBOCInQm78QAkxFOSpFhr9I5suJsqS9ztd+4m9D0NbzkMWLJIkB+jHL9jCTsXEpCJALSL1q70c= X-Received: by 2002:ab0:2695:0:b0:352:5fc9:4132 with SMTP id t21-20020ab02695000000b003525fc94132mr8054004uao.29.1651034333089; Tue, 26 Apr 2022 21:38:53 -0700 (PDT) MIME-Version: 1.0 References: <20220407031525.2368067-1-yuzhao@google.com> <20220407031525.2368067-8-yuzhao@google.com> <87zgk7xi13.fsf@linux.ibm.com> In-Reply-To: <87zgk7xi13.fsf@linux.ibm.com> From: Yu Zhao Date: Tue, 26 Apr 2022 22:38:17 -0600 Message-ID: Subject: Re: [PATCH v10 07/14] mm: multi-gen LRU: exploit locality in rmap To: "Aneesh Kumar K.V" Cc: Stephen Rothwell , Linux-MM , Andi Kleen , Andrew Morton , Barry Song <21cnbao@gmail.com>, Catalin Marinas , Dave Hansen , Hillf Danton , Jens Axboe , Jesse Barnes , Johannes Weiner , Jonathan Corbet , Linus Torvalds , Matthew Wilcox , Mel Gorman , Michael Larabel , Michal Hocko , Mike Rapoport , Rik van Riel , Vlastimil Babka , Will Deacon , Ying Huang , Linux ARM , "open list:DOCUMENTATION" , linux-kernel , Kernel Page Reclaim v2 , "the arch/x86 maintainers" , Brian Geffon , Jan Alexander Steffens , Oleksandr Natalenko , Steven Barrett , Suleiman Souhlal , Daniel Byrne , Donald Carr , =?UTF-8?Q?Holger_Hoffst=C3=A4tte?= , Konstantin Kharlamov , Shuang Zhai , Sofia Trinh , Vaibhav Jain Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: n56e61bqifwt7e6ztst7h6e8up3qjiw7 Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=fJc1sFC+; spf=pass (imf21.hostedemail.com: domain of yuzhao@google.com designates 209.85.222.42 as permitted sender) smtp.mailfrom=yuzhao@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: E5C8F1C005A X-HE-Tag: 1651034330-674014 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Apr 26, 2022 at 10:33 PM Aneesh Kumar K.V wrote: > > Yu Zhao writes: > > .... > > diff --git a/mm/rmap.c b/mm/rmap.c > > index fedb82371efe..7cb7ef29088a 100644 > > --- a/mm/rmap.c > > +++ b/mm/rmap.c > > @@ -73,6 +73,7 @@ > > #include > > #include > > #include > > +#include > > > > #include > > > > @@ -821,6 +822,12 @@ static bool folio_referenced_one(struct folio *folio, > > } > > > > if (pvmw.pte) { > > + if (lru_gen_enabled() && pte_young(*pvmw.pte) && > > + !(vma->vm_flags & (VM_SEQ_READ | VM_RAND_READ))) { > > + lru_gen_look_around(&pvmw); > > + referenced++; > > + } > > Is it required to update referenced here? we do that below after > clearing the young bit. Or is the goal to identify whether we found any > young pte around? referenced++ is needed because lru_gen_look_around() also clears the young bit in pvmw.pte. And ptep_clear_flush_young_notify() will return false unless mmu notifier returns true. > > + > > if (ptep_clear_flush_young_notify(vma, address, > > pvmw.pte)) { > > /*