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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=ham 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 690BBC47088 for ; Wed, 26 May 2021 23:03:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D94BA613D2 for ; Wed, 26 May 2021 23:03:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D94BA613D2 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2D4496B0036; Wed, 26 May 2021 19:03:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2AAE06B006E; Wed, 26 May 2021 19:03:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 125206B0070; Wed, 26 May 2021 19:03:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0064.hostedemail.com [216.40.44.64]) by kanga.kvack.org (Postfix) with ESMTP id D728B6B0036 for ; Wed, 26 May 2021 19:03:37 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 6C2D1181AEF30 for ; Wed, 26 May 2021 23:03:37 +0000 (UTC) X-FDA: 78184910874.30.09453B3 Received: from mail-lf1-f47.google.com (mail-lf1-f47.google.com [209.85.167.47]) by imf23.hostedemail.com (Postfix) with ESMTP id BBD7FA0001D5 for ; Wed, 26 May 2021 23:03:30 +0000 (UTC) Received: by mail-lf1-f47.google.com with SMTP id w33so5026184lfu.7 for ; Wed, 26 May 2021 16:03:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=2ZAwr+uWe1RDh6PrvXQCTvhQUq67NZKbIFSU2NmGCms=; b=DInztS5vf5H0IuXW0bNB2j/bEcRgqdeBKI3unl909a7pWSL4CZS3Tpy3WBmmUC0gQY f68bgDCxLBTVFTAeX0sz7iharrOIYJSyiL9a4g2if77wv6Kt4MMDG5PxQWPy2jEvRogq JHf9kdJz1NqntFyp92Ws2ydglgYZOR2wRU1uEqQqVja7yEfpbEKpjNq093b4E1xcZR/l 3t8Ry09STINW1tp0ja6ia3P1FQ23E8rW2vntCvdsVevBk3LOb0+d26/1qDeV1Pfr9gQZ mFJZUPSR3GZpNKfvPFAoPmlR1k0qTLgF5nqRDSayzEjb4ePVni/0iGYbri7sNWNt+q8z e3jw== 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=2ZAwr+uWe1RDh6PrvXQCTvhQUq67NZKbIFSU2NmGCms=; b=OEX8vc+pYd6Vdl28QLnr2Ltbasr5L9NQyiH+GMV4dSvEcROMwMzF955ueFS/c0CIPm sXldE4i9sx6KcduS6nxp1I1DfTHsIskTgtrdwpNrrxigm9bzwHqaod5Omk+cdm/nmw0A UyM1fDo+HZTHvruBL77hkwP8ZoeA3G/qI5krwnnM9dXLwCX4sjEDBHkHJBbw7qXKXsPL s+dhCbCcCq2sQ/GvgoU+ciGoQZuU504TEa88vVgA9mZ1DZVmiPZtI5EDrTcOHwto4vF1 vE/K2VMxqWgh5tbVISzarcejfRwQKqEw6mBNfExgshObljikJ6e6Pw4lqQPL2GFyG7JO Yhcg== X-Gm-Message-State: AOAM532BFVz31kleuM9MqGaSee3puFS/sNXHeNWYbXAumdduCfeEcMxt Athc17pWtHfAkil4JwI0929nVZWdfxXTOCDTsnvyMw== X-Google-Smtp-Source: ABdhPJwVNK5U1mLQGbtiooe5DWoQS/py60QeZeqjo8+tyrjQRST7xi1Cw3dVr1w2aBB8MPL7N55L07DFRCvJvmC/z0Y= X-Received: by 2002:a19:7012:: with SMTP id h18mr285616lfc.432.1622070215096; Wed, 26 May 2021 16:03:35 -0700 (PDT) MIME-Version: 1.0 References: <20210526201239.3351-1-shy828301@gmail.com> <20210526201239.3351-2-shy828301@gmail.com> In-Reply-To: <20210526201239.3351-2-shy828301@gmail.com> From: Shakeel Butt Date: Wed, 26 May 2021 16:03:23 -0700 Message-ID: Subject: Re: [v4 PATCH 2/2] mm: rmap: make try_to_unmap() void function To: Yang Shi Cc: Hugh Dickins , Zi Yan , "Kirill A. Shutemov" , Minchan Kim , naoya.horiguchi@nec.com, wangyugui@e16-tech.com, Andrew Morton , Linux MM , LKML Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: BBD7FA0001D5 Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=DInztS5v; spf=pass (imf23.hostedemail.com: domain of shakeelb@google.com designates 209.85.167.47 as permitted sender) smtp.mailfrom=shakeelb@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Server: rspam04 X-Stat-Signature: wiprsyp56aod5mpqwh33nzxr35eof6nj X-HE-Tag: 1622070210-808927 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 Wed, May 26, 2021 at 1:12 PM Yang Shi wrote: > > Currently try_to_unmap() return bool value by checking page_mapcount(), > however this may return false positive since page_mapcount() doesn't > check all subpages of compound page. The total_mapcount() could be used > instead, but its cost is higher since it traverses all subpages. > > Actually the most callers of try_to_unmap() don't care about the > return value at all. So just need check if page is still mapped by > page_mapped() when necessary. And page_mapped() does bail out early > when it finds mapped subpage. > > Suggested-by: Hugh Dickins > Acked-by: Hugh Dickins > Signed-off-by: Yang Shi Reviewed-by: Shakeel Butt