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 70B48FF8868 for ; Mon, 27 Apr 2026 15:02:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B1A526B008A; Mon, 27 Apr 2026 11:02:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id ACA536B008C; Mon, 27 Apr 2026 11:02:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9E4706B0092; Mon, 27 Apr 2026 11:02:23 -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 8DAD76B008A for ; Mon, 27 Apr 2026 11:02:23 -0400 (EDT) Received: from smtpin21.hostedemail.com (lb01b-stub [10.200.18.250]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 612441A0D79 for ; Mon, 27 Apr 2026 14:59:34 +0000 (UTC) X-FDA: 84704644668.21.73D6E38 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf14.hostedemail.com (Postfix) with ESMTP id AE9F0100013 for ; Mon, 27 Apr 2026 14:59:31 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=DOppvcSt; dmarc=pass (policy=none) header.from=infradead.org; spf=none (imf14.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1777301972; 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=LnSYo4u0L2Q6YEjx0+dHXcL7aARLporXLzc/o3YTey4=; b=qP2HfnXdtMP0zQb+M1xwy9GcSDD135jz2zBvsidpSvAjLNHO6w9JKw1K2EBTMbBSXRVZsP fxdUxsaUdhQ24Q7qAnGYf/wy/sBdXnisSc51S8RDcE2cEdCvPel7/jBiRZ9tBcyfkQQNso Z1NBGoVcifPHDYFy8e4sLuFlzV6mQ1k= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1777301972; a=rsa-sha256; cv=none; b=H7a/0dkPk4D0WO2rDjgy0fM4gCCS38tg9xr3UGPumgwWsHvS5z7sYx+0iK+2mRJZBfF4+f AxnJkh0Vore00Y2FAtCLFgCKr0wo6ejypAu673TehHsyK/YJWoNzwe9v1jR3WEPZjdCIEr 4mr80VkgLgl50zeSfsa+tqXlwd7Ypu8= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=DOppvcSt; dmarc=pass (policy=none) header.from=infradead.org; spf=none (imf14.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=LnSYo4u0L2Q6YEjx0+dHXcL7aARLporXLzc/o3YTey4=; b=DOppvcStsIhCJdrfUDmQHbkpCJ vxt0xZj3PArO+3swzACOj4C6ddv3xiAtzOO4ch4r7SyyXSWN1W7zY5CUtupWFw0m2E2SbGXzE+kZ3 yL2OlsnQgQi15x+WC/xPVcoEDOgM08hL1VxXOyuf84KNTxkTz3HU8LvfQEvD9/Axy6xc1UA4i1h+j EzXXiz/ixQIzlFf4xixGXeiavCpXi+uXv6CgT2bV/+hduPx/4EH6OEt8iWXDy9eC6arzbycDw5yLw pgudYhnMvaduKk82qPgPyzSo6SxXaG+M5YErrZcBE84J2+4uQ2ZXnY7v91KeC2VFFzgoqPLv8OTRh wChocelQ==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1wHNQa-00000002Eyk-3fVi; Mon, 27 Apr 2026 14:59:16 +0000 Date: Mon, 27 Apr 2026 15:59:16 +0100 From: Matthew Wilcox To: Breno Leitao Cc: "David Hildenbrand (Arm)" , Andrew Morton , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi , Song Liu , Yonghong Song , Jiri Olsa , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Rik van Riel , Harry Yoo , Jann Horn , "Liam R. Howlett" , linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 3/3] mm: remove page_mapped() Message-ID: References: <20260427-page_mapped-v1-0-e89c3592c74c@kernel.org> <20260427-page_mapped-v1-3-e89c3592c74c@kernel.org> <20260427062137.48739e6fa6e550f1f0e8ff48@linux-foundation.org> <06218a87-8346-40b4-adf4-dc494b5f1293@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Queue-Id: AE9F0100013 X-Rspamd-Server: rspam04 X-Stat-Signature: efexz6n53spkasfq6tmyz3jzu3zd1ijr X-HE-Tag: 1777301971-747835 X-HE-Meta: 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 Z2wYGf+G /Xz6/F34DXBrKhVGVcyeehlRr38zx/QDN8WAR+aIHEULedHwpF2ds/4quUSmM1BSRmvl+1BxOr5h0WYoXflLW4QGnGudG+vIKpsMak7RQW7t6itFLrQraJu9D67lVStnsG8TaOmKUjeezZAzcp4kk2f8cX7kzjByWfdMh9sBE7m9VQWGBraiazNJLTmXgi9fNt25XWzBv+1o9M2PCTdBDpliPysacMB9fWfDQ+bsSayde3VNRUsSG21iKIMcCtJm22qxSQkY8T8x//VSSqPdplXkpp4WuMapkgeLZtOhYlzmcNpE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Apr 27, 2026 at 07:42:46AM -0700, Breno Leitao wrote: > > > @@ -1353,7 +1353,7 @@ static bool panic_on_unrecoverable_mf(un > > > cpu_relax(); > > > return page_count(p) == 0 && > > > !PageLRU(p) && > > > - !page_mapped(p) && > > > + !folio_mapped(page_folio(p)) && > > > !page_folio(p)->mapping && > > > > If we have a folio, we should really lookup the folio once. Not 4 times. > > Why 4 times? Because there are page_folio() calls hidden in PageLRU, page_mapped() and page_count(). > > Breno's patch likely needs some love. :) > > Would something like the following give it all the love in the world? > > folio = page_folio(p); > return page_count(p) == 0 && > !PageLRU(p) && > !folio_mapped(folio) && > !folio->mapping && > !is_free_buddy_page(p); No. You need to immerse yourself more deeply in the folio transition ;-)