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 C1645C88E53 for ; Tue, 15 Sep 2026 09:04:32 +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=xj97Gm+bFVDZhjwESgxXGsr/TcYPbbFLUTQH8EasuOs=; b=DvC1Bi6B8fs2ije3avKARdA18G 9nPEZ0uLCC+hsJHb0oS8usGd8Cb5nS6qYFrcOv5o4YxSKy1/8Cjtt35urocKjcStJyX/TG61Gbcvs TBTeuCo1n9R+kG1keikMPRBRf9Q1hHePIj0eag1SYrQrDk7oxg18rw0C8FLo5JCGEPXO9798aAay/ k38S//eBPnuj+iPDtNDl8Dm7soFn+3ebjLjdP+51EVdO7YmKy/X2kI/J0sOJHjEK7dtrsomwaPAwf WuhKblkOtGKgERIijym4SwGcH5wmo9w6ItIFkVeYmguX2jHLnE8SR4DKFg2vnAVnmivSfd5qFbYar waLTu3jA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6P5a-00000005jUK-2TxA; Tue, 15 Sep 2026 09:04:30 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6P5U-00000005jUA-1YON for kexec@bombadil.infradead.org; Tue, 15 Sep 2026 09:04:24 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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=xj97Gm+bFVDZhjwESgxXGsr/TcYPbbFLUTQH8EasuOs=; b=ONO90DiDxTHtIgUgWFtThPVUIL BXAlSt4ayxoDAhEG5tpM7bBXuHJBdmmjYOEAE20w03J/05fkhei7QmmCRaB5Jr4DwFImxIVu40/6D JTYUUeCPnlv5G42UyEoAw5byK43Cc2f/GER3WxoxxnuygD7Kdt6PZv/orS4zxQP8yl7Et/GfkBxKi mj4YMLVX4kxYcX6duq2ScZy14ck0oCBSqPE8k6muFBbO29U9GuUHMUV4MFwFXX7z5FRNWT44GLZkz +snNoZHw5kZrOoEZB2OCkG0NeJKlRQH8V9I51FsvyENoDv+hJhDAdPWHenFqVflDEqtlLB+Dyw7yr /5ykPHyQ==; Received: from stravinsky.debian.org ([2001:41b8:202:deb::311:108]) by desiato.infradead.org with esmtps (Exim 4.99.2 #2 (Red Hat Linux)) id 1x6P5R-00000006TPL-1ou1 for kexec@lists.infradead.org; Tue, 15 Sep 2026 09:04:23 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=xj97Gm+bFVDZhjwESgxXGsr/TcYPbbFLUTQH8EasuOs=; b=lRl6heYdFmWobjqmP6MVFkL3cc hrfWmOjJy7y8JC4vaFY0trfhscwmnfFCx1TYA24UxzrPt41+U6Va+vFZDeo0p8FcrkDmBpzjqVsgk JPSe9jy/AB4dPNiYIpvuvQxdT30cSTNu7IIhDxsViLxrY5mk/yPbs+ARWqEFH2WX3MI9gNbnBwrqb ytBsRGkqSb7XmPuwpl/2f6Mr7KW5Uo2R/ImOZsT+mPaFhkFGTH2UfO/Dd+a9OIIJ30Hcc4lFqiRhc vl/N2nSH9zs66d5eQQM/R4y4PtD/9V0nDRpXZEkq7o/gZMcDF6vJOmqeMv6iu2rs80VEGFFXzMAsF oKG4ogTQ==; Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1x6P51-004HQC-0I; Tue, 15 Sep 2026 09:03:55 +0000 Date: Tue, 15 Sep 2026 02:03:48 -0700 From: Breno Leitao To: Ard Biesheuvel Cc: Ilias Apalodimas , Miaohe Lin , Naoya Horiguchi , Andrew Morton , "Kiryl Shutsemau (Meta)" , kexec@lists.infradead.org, David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Brendan Jackman , Johannes Weiner , Zi Yan , linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, rmikey@meta.com, riel@surriel.com, harry@kernel.org, kernel-team@meta.com Subject: Re: [PATCH v4 2/5] mm/memory-failure: libstub: install the poisoned-memory EFI table Message-ID: References: <20260909-hwpoison-kho-v4-0-359313564495@debian.org> <20260909-hwpoison-kho-v4-2-359313564495@debian.org> <2c9a7bef-3189-4f78-a6cb-61d2f7afd643@app.fastmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Debian-User: leitao X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260915_100421_592802_39F66024 X-CRM114-Status: GOOD ( 12.01 ) 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 On Thu, Sep 10, 2026 at 06:11:53AM -0700, Breno Leitao wrote: > So I'd say we have two options: > > 1) Keep it similar to unaccepted memory, with 2M granularity. > - Pro : Similar mental model as unnacepted memory > - Cons: 2 MB might be a bit wasteful > > 2) Move to a linked list like the RFC, keeping it outside of the EFI > table. > - Pro: Reduce the memory granularities to page instead of 2M blocs. > - Cons: Another way of passing memory information between kexec > kernels. > > Any any other option or strong preference? Since nobody voiced a strong preference, I will stick with option (1), the bitmap, for these reasons: 1) It follows the same mental model as unaccepted memory, which people are already familiar with. 2) It is simpler to query at boot time, especially as the number of poisoned memory regions grows. Walking a bitmap is easier than walking a linked list when freeing memory back to the buddy allocator. --breno