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, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 85C2DC433DF for ; Mon, 25 May 2020 04:55:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6243F207DA for ; Mon, 25 May 2020 04:55:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=shutemov-name.20150623.gappssmtp.com header.i=@shutemov-name.20150623.gappssmtp.com header.b="Fdz79PEv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728057AbgEYEzU (ORCPT ); Mon, 25 May 2020 00:55:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726649AbgEYEzU (ORCPT ); Mon, 25 May 2020 00:55:20 -0400 Received: from mail-lf1-x141.google.com (mail-lf1-x141.google.com [IPv6:2a00:1450:4864:20::141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01E25C061A0E for ; Sun, 24 May 2020 21:55:19 -0700 (PDT) Received: by mail-lf1-x141.google.com with SMTP id x22so9789695lfd.4 for ; Sun, 24 May 2020 21:55:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=ta+gKITSaDFXbddptw1PycpUmizB8GirSrm5Sv99kI8=; b=Fdz79PEvtruLyLOx8oikptAOCD4uLGZYUKf1BFLDTPaj2cCbCMlhFQgMqqfETPXX0x AZ9H/1r4wGJy6VRcXJewAODKxPYihv6kv2xeyw6i9VmKCxCJFSVSMu3mSMNlQXWKqPul 8M8HIvIARh9/Ir9GBQ4dqjSwskZasNX09MdwpC1p6N868SwXgAmqK4Z4AfWvhuYer0w/ qnZILt634RDRm63MKcOmX2aCh3Ji8myuncnMyir4GjFHUU+GSIAgpt4lBHwLwsv5Jg8J /jjH3FDU8tmASZnfRtMi6vBvRRNrvtwuAImxJdLmkJ7wCZhtUIXTqICJTEjyv8mzZ5ep ZKSQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=ta+gKITSaDFXbddptw1PycpUmizB8GirSrm5Sv99kI8=; b=LwkHsxIAE37vIplak/S6suxLt5B3GfQpHV1O6lazBL9QplQ/vINtUEWGHniOxC68q2 02nF5ZwlzfOX7Sgoz5HZaO/tmjRDEa+NlGDtwNPR2C4l7UHbJttsvoiGvzhDBBYSLNL6 TY1mBX6/C7kZl1RCJyFyEMG48wBLsAOqUhMGSm3wBxXWgIpAR63m36G7gnf/rTxk1YK0 OOHbW0yDg5yPX8NI7246HyPEabZy7xJ0b29myQtb8QM8Uci3el3zn5RKPGLyghENoknb G/AAcSCnzYLtxpokKWBaKQpPK8TDSoGynN7Y4miQ/kRsFUTb0VaJ05iB72iwdExzJs/R BARw== X-Gm-Message-State: AOAM530oJyff2xPi7CBftb2dMV/uayja1HDlXSCoT4MvUNx5ILRykI+w eagMGBWdJYaCcXOYsnRq5RVU/h20Fr4= X-Google-Smtp-Source: ABdhPJxHYXGYhHPr163MFt0+8DI04wONMTR8geyOar2shTxMyVvgmv7QPrP+pQhnhBRd9z6ng0Fxgg== X-Received: by 2002:a19:5f04:: with SMTP id t4mr13359691lfb.208.1590382518277; Sun, 24 May 2020 21:55:18 -0700 (PDT) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id t27sm3321814ljo.114.2020.05.24.21.55.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 24 May 2020 21:55:17 -0700 (PDT) Received: by box.localdomain (Postfix, from userid 1000) id 558C01012E6; Mon, 25 May 2020 07:55:18 +0300 (+03) Date: Mon, 25 May 2020 07:55:18 +0300 From: "Kirill A. Shutemov" To: Matthew Wilcox Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 11/36] fs: Support THPs in zero_user_segments Message-ID: <20200525045518.ydro3k2h5ct3pxxj@box> References: <20200515131656.12890-1-willy@infradead.org> <20200515131656.12890-12-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200515131656.12890-12-willy@infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, May 15, 2020 at 06:16:31AM -0700, Matthew Wilcox wrote: > From: "Matthew Wilcox (Oracle)" > > We can only kmap() one subpage of a THP at a time, so loop over all > relevant subpages, skipping ones which don't need to be zeroed. This is > too large to inline when THPs are enabled and we actually need highmem, > so put it in highmem.c. > > Signed-off-by: Matthew Wilcox (Oracle) > --- > include/linux/highmem.h | 15 +++++++--- > mm/highmem.c | 62 +++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 71 insertions(+), 6 deletions(-) > > diff --git a/include/linux/highmem.h b/include/linux/highmem.h > index ea5cdbd8c2c3..74614903619d 100644 > --- a/include/linux/highmem.h > +++ b/include/linux/highmem.h > @@ -215,13 +215,18 @@ static inline void clear_highpage(struct page *page) > kunmap_atomic(kaddr); > } > > +#if defined(CONFIG_HIGHMEM) && defined(CONFIG_TRANSPARENT_HUGEPAGE) > +void zero_user_segments(struct page *page, unsigned start1, unsigned end1, > + unsigned start2, unsigned end2); > +#else /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */ > static inline void zero_user_segments(struct page *page, > - unsigned start1, unsigned end1, > - unsigned start2, unsigned end2) > + unsigned start1, unsigned end1, > + unsigned start2, unsigned end2) > { > + unsigned long i; > void *kaddr = kmap_atomic(page); > > - BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE); > + BUG_ON(end1 > thp_size(page) || end2 > thp_size(page)); > > if (end1 > start1) > memset(kaddr + start1, 0, end1 - start1); > @@ -230,8 +235,10 @@ static inline void zero_user_segments(struct page *page, > memset(kaddr + start2, 0, end2 - start2); > > kunmap_atomic(kaddr); > - flush_dcache_page(page); > + for (i = 0; i < hpage_nr_pages(page); i++) > + flush_dcache_page(page + i); Well, we need to settle on whether flush_dcache_page() has to be aware about compound pages. There are already architectures that know how to flush compound page, see ARM. -- Kirill A. Shutemov