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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3A69AC982EA for ; Wed, 23 Sep 2026 09:24:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3253A6B0092; Wed, 23 Sep 2026 05:24:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2D6176B0096; Wed, 23 Sep 2026 05:24:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1EC5E6B0098; Wed, 23 Sep 2026 05:24:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id EEDAB6B0092 for ; Wed, 23 Sep 2026 05:24:54 -0400 (EDT) Received: from smtpin10.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 63E0B14062A for ; Wed, 23 Sep 2026 09:24:54 +0000 (UTC) X-FDA: 85244492508.10.541EB23 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf15.hostedemail.com (Postfix) with ESMTP id B8E5EA000B for ; Wed, 23 Sep 2026 09:24:52 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="lf/HJYmS"; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf15.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790155492; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=rLKRb8Y4+nISCnQaxnX4ctxBf/lcPEd8M1PAoqnsICk=; b=7meJxyJaNnWgF64rLN9Ra/WX+06YX8ImkV5RftVraZrSzG0oA4vjWrgv/2G3wSnj6B4HvR 7r9YV8Ys6rXcL6FGL7ywWouHKdfEbt398IkFL3t5fHARon4QLzuYKDzwmayHBKCUsEwKB/ D3DcNVVFnNTm9VRDuRlQo7iKng8+drU= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="lf/HJYmS"; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf15.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790155492; b=7zsWIT+mOlRGk+O/juFs4MGEQ8OQDqS0rXXs63ISC9l10SJ0yQK8h9dmQCSrm3FBLqCv7m sHRzfk7CaVyemA4+1zuCYiDX94puqBpJYUhfZ08Th+CNbMjNNd+4g0cHdo2iheyg9aF0m4 VO8zuKtEWJBhrJEVIi9Gq8bY6JaaGeg= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id D327242E13; Wed, 23 Sep 2026 09:24:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F05E1F000FF; Wed, 23 Sep 2026 09:24:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790155491; bh=rLKRb8Y4+nISCnQaxnX4ctxBf/lcPEd8M1PAoqnsICk=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=lf/HJYmS7UTiPzh9amAhYD2S1aZFVo3LNH5rJLGdyYuILAzd5aGZtD7Z+A88a9tmL hHM6MECEikQkwhUsVWW9OiN+brnRisqJ9m4BU9synUw13IBOU89ZTDelvYTT+MbfCr YHCOAWS4p2NquBk89ID0zbIa8fuQleDE9KqU4RAhKfHJPAKRRbVI/pQHilGVcicP07 EW/UgyDgmSBMmHsdSA0fJ+c0tZ/MA4+6VdDCVG/bt0KetNYvzUPxCl4XaT+mMKf/Jf B1arbqfvaLL4O7tkudrCw1fmUe8fqQeMQ5Yhy/QP0Sg91jXC39kkSIBIAWf4RbKs6W EnUBG7zakOYgg== Date: Wed, 23 Sep 2026 12:24:43 +0300 From: Mike Rapoport To: Tal Zussman Cc: Andrew Morton , Baoquan He , Pasha Tatashin , Pratyush Yadav , Dave Young , linux-mm@kvack.org, linux-s390@vger.kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev Subject: Re: [PATCH] vmcore: convert mmap_vmcore_fault() to use folios Message-ID: References: <20260915-vmcore-fault-folio-v1-1-a0cb6278670f@columbia.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260915-vmcore-fault-folio-v1-1-a0cb6278670f@columbia.edu> X-Rspamd-Queue-Id: B8E5EA000B X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: 5kiyisygx7xs8z4q79ah8h1fxj3yu8iq X-HE-Tag: 1790155492-449475 X-HE-Meta: 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 tIYZ1ovT +4l9C/sKyIqhbOjQDlwTdr5y36SwhLL1gzADjos3XOzbP3yWxzghknndx32MxpF6By0HVlILkqLXpybSJse6e4wBasOtYlXAjvYJQCNqVVq57xJ5BjBtcM8IWOnA4Jr9rSKynFJfAZNDgqdoEgEEO9pswcD5J4qs1oPnZBiSUZgLP6QYJmwJ+1k8DBAoQB7J3KKQtfoMCgGGAvZQD00LWFtEXzYKqrl0Ofcc4YrZINjAcFU7VbFHADss/+fDz2jwWV5ezODEpkz66UuYweODqnim3q5ovakxAA7ewJL7qaA9LsJUSqOXgBOgarw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: (cc s390 folks) On Tue, Sep 15, 2026 at 07:42:15PM -0400, Tal Zussman wrote: > Use a folio for the page cache page the s390 fault handler reads the I tiny bit of context why is this only relevant for s390 would have been nice :) > old kernel's memory into. This removes four compound_head() calls and > one of the last callers of find_or_create_page(). > > The vmcore mapping only has order-0 folios, so the logic is unchanged. > > Compile tested for s390. > > Signed-off-by: Tal Zussman > --- > This is based on the kexec-next branch of the liveupdate tree. > --- > fs/proc/vmcore.c | 27 ++++++++++++++------------- > 1 file changed, 14 insertions(+), 13 deletions(-) > > diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c > index 44d15436439f..2dc3803aa11d 100644 > --- a/fs/proc/vmcore.c > +++ b/fs/proc/vmcore.c > @@ -474,29 +474,30 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf) > pgoff_t index = vmf->pgoff; > struct iov_iter iter; > struct kvec kvec; > - struct page *page; > + struct folio *folio; > loff_t offset; > int rc; > > - page = find_or_create_page(mapping, index, GFP_KERNEL); > - if (!page) > + folio = __filemap_get_folio(mapping, index, > + FGP_LOCK | FGP_ACCESSED | FGP_CREAT, GFP_KERNEL); > + if (IS_ERR(folio)) > return VM_FAULT_OOM; > - if (!PageUptodate(page)) { > - offset = (loff_t) index << PAGE_SHIFT; > - kvec.iov_base = page_address(page); > - kvec.iov_len = PAGE_SIZE; > - iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, PAGE_SIZE); > + if (!folio_test_uptodate(folio)) { > + offset = folio_pos(folio); > + kvec.iov_base = folio_address(folio); > + kvec.iov_len = folio_size(folio); > + iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, folio_size(folio)); > > rc = __read_vmcore(&iter, &offset); > if (rc < 0) { > - unlock_page(page); > - put_page(page); > + folio_unlock(folio); > + folio_put(folio); > return vmf_error(rc); > } > - SetPageUptodate(page); > + folio_mark_uptodate(folio); > } > - unlock_page(page); > - vmf->page = page; > + folio_unlock(folio); > + vmf->page = folio_file_page(folio, index); > return 0; > #else > return VM_FAULT_SIGBUS; > > --- > base-commit: 4d17a004cfd5489f88ad0a7a151dea11a533338b > change-id: 20260907-vmcore-fault-folio-4b382eeff262 > > Best regards, > -- > Tal Zussman > -- Sincerely yours, Mike.