From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 83F3C2E7657; Mon, 29 Dec 2025 21:15:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767042902; cv=none; b=htROyRBHr7KchrRfKBKOsk5rYCMz5p0n0u+HOzvP2Ku1D49z+kA6HIWIc8W+a4LdG6GrVB1K0Lac4Hbyx4HOjLKJThe5b3tmZH37ja+Wp1sT+pK6Mc8NTJehuNleBHOYHbygTZAbtySpdH6EAjdEPPvBdE8/FgOWb+19+TvDS0o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767042902; c=relaxed/simple; bh=+0hKzidYvfWG+s9TtusbziTKi6XLXUnZ4Y1pxbN7Jvc=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=uC3FHX9aD3lm+BNY+L8J2YGhEAkzXiE8TzniMY6tiSVVGsyAgzNQnu4k7DISVpghQQCQ2CtvYzS5fBfdH9+4ss5DffNd1FJMyjl0D8vFplTfPvYOUK1fRUWftNMGMoAnvGUQefZIMal9H2E3YHl6/PCX/U3ZibZkd6uOroxubzQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jKY9UZls; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jKY9UZls" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9E38C4CEF7; Mon, 29 Dec 2025 21:14:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767042902; bh=+0hKzidYvfWG+s9TtusbziTKi6XLXUnZ4Y1pxbN7Jvc=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=jKY9UZlsTOJCp8mrSaW/YOoqI/r+yyNyFf2huGx4VFftVsJRCMpS4UchEWmSNJU2+ mmW/SR65hRZs3p/IS7waf1NjQ9aTDSyuxztBD1pNzRqCoQF95mGqFK75bOE8qiOsTh r/34jl6+cJGesKLtTSrG0wiDLX0xjY3kxFF0yDM8QokptRaq8I7jRQ4niRqABeII49 A8Rz7bg+1ZrAHDw6vrD56WZ/IhNI7SrXFPMEOUt9GgTg5RArbxf9AqMyAQ0D8X7rC8 ZOtaBzMp1jsL14bwuklPgimM0VCDonLAQ3ZKPaY9/XbQn4TXWFX/cGXEO9V0n2jsnv Kjh2IexLkouyA== From: Pratyush Yadav To: Pasha Tatashin Cc: Pratyush Yadav , Mike Rapoport , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Muchun Song , Oscar Salvador , Alexander Graf , David Matlack , David Rientjes , Jason Gunthorpe , Samiullah Khawaja , Vipin Sharma , Zhu Yanjun , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, kexec@lists.infradead.org Subject: Re: [RFC PATCH 08/10] mm: hugetlb: disable CMA if liveupdate is enabled In-Reply-To: (Pasha Tatashin's message of "Tue, 23 Dec 2025 13:16:57 -0500") References: <20251206230222.853493-1-pratyush@kernel.org> <20251206230222.853493-9-pratyush@kernel.org> Date: Mon, 29 Dec 2025 22:14:50 +0100 Message-ID: <86v7hp7zxx.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Tue, Dec 23 2025, Pasha Tatashin wrote: > On Sat, Dec 6, 2025 at 6:03=E2=80=AFPM Pratyush Yadav wrote: >> >> Hugetlb live update support does not yet work with CMA. Print a warning >> and disable CMA if the config for live updating hugetlb is enabled, and >> liveupdate is enabled at runtime. > > Could you please elaborate this commit to explain why it is not > supported, and what it would take to support CMA. The main reason is that when HugeTLB CMA is enabled, the huge pages come from CMA. If we have preserved pages, we would need to "insert" those pages into the CMA when they are restored. CMA does support multiple ranges, so I suppose it can be done, but it needs some plumbing to work properly. Will add this in the next revision. --=20 Regards, Pratyush Yadav