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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5F331C98309 for ; Wed, 23 Sep 2026 09:24:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=rLKRb8Y4+nISCnQaxnX4ctxBf/lcPEd8M1PAoqnsICk=; b=olTwOafXUip+/wUiVXuHWlKCLY LJ5I/KY07+Ik4YYwOjHPon61jpEUjzxmMioOeirQExbrXHMZsZ6TZNoQzmfkiE1neBdI+ONtRX/gI idWhiA9hVj5SNJ3vIPYHCYExjoKXVPAZQRUtYCRyJBNYQxCCFOeNszvOI70JY76m1xJ9hHjYuOF43 9uUY5FX2JyZdPcKl4J/0GGWSbMaRt1soQcBDNlyc3DV++ZjQUXwN4ow8hJrb1PRu0XwGdNqkXYGwR yuBiqGBu5MJuQvF5wNabQi48cDbKt/Uxu/4sX+vJhK3dyeEc4ZXFnUcwch7S/ad2WLi/sFVApEWAL CCRgDDww==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x9JDi-00000007iq4-0Zm8; Wed, 23 Sep 2026 09:24:54 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x9JDg-00000007ipg-1lbT for kexec@lists.infradead.org; Wed, 23 Sep 2026 09:24:52 +0000 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-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org (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.