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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8F484C2D0E5 for ; Fri, 27 Mar 2020 17:47:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 68A222072F for ; Fri, 27 Mar 2020 17:47:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ifx83egn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727505AbgC0RrM (ORCPT ); Fri, 27 Mar 2020 13:47:12 -0400 Received: from mail-ed1-f65.google.com ([209.85.208.65]:39769 "EHLO mail-ed1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726540AbgC0RrM (ORCPT ); Fri, 27 Mar 2020 13:47:12 -0400 Received: by mail-ed1-f65.google.com with SMTP id a43so12268961edf.6 for ; Fri, 27 Mar 2020 10:47:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=vl6M74fDKYNuH8RGWdOOCCv6ZP4dyjZ70PvCE1aC7GQ=; b=ifx83egnh61+hG/1a0lKBCQCmLlYS9+TKE+Yo3jgRE3LY7l7hLz+snpkDi/TJfnVSo tozJDHdlNGXlcu4jyUPuBaxB6Le71WOzFH6gUuhaj+D5ulqcJwDOZ/SvwNYbBfzYsMel OWTo+1fWpuyt+QKJzDVCvTfHemqcIeZZ1x2ajI2q3YDrc+5NAwXCxbE8rHylR2Ku+rGp CBU8rEnP3WuDCbrzGRxD/Fslrkh0syCkk4Pt6KVofOhljNAZJAXXxPnS4Z+1rwecUeOu 9JK1d8Fg0FHBN27uz7b7z181nfV9IwQPLyLjlhMp/hN8AiL3Uf/8EDDkg+WA4g6FTfHu 5cEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=vl6M74fDKYNuH8RGWdOOCCv6ZP4dyjZ70PvCE1aC7GQ=; b=kUPLt+0bpfGMk0b82tb8z196vRj/4MA4cdwb5jFxbE/Ib+VquEmrfU6ACV6R7av7AY cyY1usHPovlqCondFJBxdXIrCdxRWJmnx4dftvEpm5sDpgW+mLbRoAmxyGa4JvZcz8NW F7MI9Ui648UjOOJrepueKoka0SBWs6x10xGDNGbUGjKajLWc1kAvFZowETC0kS2slZM5 MwQbJmyJ/M1hEy7Sn623/kiQK38yDXXnF76/8vOwy5vNIzRYL1DJALDVIXm3HFAfvBxt s0dHX1jclN6nBveEkJScksKk7p8ow5lKhYZh7DTOgjlM6J9/AXmeqqh7kKauUiYsYV9+ QCiw== X-Gm-Message-State: ANhLgQ397rJLVD1kFBB81WqeL/ay3fr97MfSU7s7IsHia1k9J75jMYYW 7Omd0aI8gFBq8f66lDHJJXdfIBp3udWm0I4kte7I6g== X-Google-Smtp-Source: ADFU+vuNz8LGvg20VvbIcfg5Bu1FdbJR4PiA5lO7bRTDYECiX0Vg2LO3/1kSphKCavJm3xzTDVkEBGFdri5vVYruHgc= X-Received: by 2002:a50:9f6e:: with SMTP id b101mr245921edf.372.1585331229996; Fri, 27 Mar 2020 10:47:09 -0700 (PDT) MIME-Version: 1.0 References: <20200327170601.18563-1-kirill.shutemov@linux.intel.com> <20200327170601.18563-3-kirill.shutemov@linux.intel.com> In-Reply-To: <20200327170601.18563-3-kirill.shutemov@linux.intel.com> From: Yang Shi Date: Fri, 27 Mar 2020 10:46:55 -0700 Message-ID: Subject: Re: [PATCH 2/7] khugepaged: Do not stop collapse if less than half PTEs are referenced To: "Kirill A. Shutemov" Cc: Andrew Morton , Andrea Arcangeli , Linux MM , Linux Kernel Mailing List , "Kirill A. Shutemov" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 27, 2020 at 10:06 AM Kirill A. Shutemov wrote: > > __collapse_huge_page_swapin() check number of referenced PTE to decide > if the memory range is hot enough to justify swapin. > > The problem is that it stops collapse altogether if there's not enough > refereced pages, not only swappingin. s/refereced/referenced > > Signed-off-by: Kirill A. Shutemov > Fixes: 0db501f7a34c ("mm, thp: convert from optimistic swapin collapsing to conservative") > --- > mm/khugepaged.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 99bab7e4d05b..14d7afc90786 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -905,7 +905,8 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm, > /* we only decide to swapin, if there is enough young ptes */ > if (referenced < HPAGE_PMD_NR/2) { > trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0); > - return false; > + /* Do not block collapse, only skip swapping in */ > + return true; > } > vmf.pte = pte_offset_map(pmd, address); > for (; vmf.address < address + HPAGE_PMD_NR*PAGE_SIZE; > -- > 2.26.0 > >