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 D3EB23B0AE8 for ; Thu, 9 Apr 2026 09:56:34 +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=1775728594; cv=none; b=VYiIRfS4hdw+PcWF1QqFSdCeTYYSn26uJ0Cpxf6a2NE32BqvomKeYG6Jq9S6jInp+egvYEpOpY59u22AA0Ew41P3JNLoQ54NVpvL4HG55sm5GIkLIVjAs5izkIfiRGlNeUfEqC3RKHu9/695Ge8KiAsVwhvi/gJE4AajaZyhsRY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775728594; c=relaxed/simple; bh=wLiR1jmbGwhcGbTJEzKKbYyUIoLx7sO83hROGWXcB0M=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=G2KqQtiSBYZkPJj8zSRLK+jWpypXulMTcaNIOHqWOkZy2+5WQ9H/sSgmLHJcHbVv4i6ske4DgA+202/ivt8QgCzATsJ9taZmO2qBSVEHJZWcLmYFZ3HnTc62Sfw4qtdxfcA8GaWv+F9US1DPUcNnhY/qjLcA8r2gJYl9TsW2x9Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EWPzUry6; 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="EWPzUry6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D46DAC4CEF7; Thu, 9 Apr 2026 09:56:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775728594; bh=wLiR1jmbGwhcGbTJEzKKbYyUIoLx7sO83hROGWXcB0M=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=EWPzUry6dvaIBTs35SPrRGMlH0v437ArhurDjAwF9Tfeh+olQS/iG7smV3CFzG1v/ EOorHW7BDETnixYZbPIvqObBG0V+hIdrGJXwRca7FmuhpWTq7PA/nbNM791APw68VY k/JyY5qaPgRoDU4Mi61P0ptK7Fe3R1QdxqhoP3aiewT4PK4L5dRqrgXO1Xec4O0w6E qteJhYjcT/jUakHW0dYpBhoKkko+OBrMgheTRYyk96A0xrIPqnnQifLhhX1rkAibOt wnBYkSikjVj9AUxTMCPNHwwOlb8AGkWN0nNNO1D6VvTIQDoYUTgf0+9ROneYCvFRiE QSob1Q/X5Ga+g== Message-ID: <63a3bd6f-c8cc-4e3c-a2b2-90163da066af@kernel.org> Date: Thu, 9 Apr 2026 11:56:29 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/2] ksm: Optimize rmap_walk_ksm by passing a suitable address range To: Lorenzo Stoakes Cc: xu.xin16@zte.com.cn, hughd@google.com, akpm@linux-foundation.org, chengming.zhou@linux.dev, wang.yaxin@zte.com.cn, yang.yang29@zte.com.cn, michel@lespinasse.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <9950c6c1-f960-58c0-4312-e4f5ac122043@google.com> <20260407142141059pWDasxUAknP5rqvAMl28K@zte.com.cn> <8332aedb-e499-4789-8f46-832df8d60224@kernel.org> <015c3268-9c95-4314-b28d-c5e33eb2fb86@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/9/26 11:53, Lorenzo Stoakes wrote: > On Thu, Apr 09, 2026 at 11:41:46AM +0200, David Hildenbrand (Arm) wrote: >> On 4/9/26 11:37, David Hildenbrand (Arm) wrote: >>> >>> Right, anon_vma_chain has. Dammit. >>> >>> >>> That's what I said elsewhere and what I was trying to avoid here. >>> >>> It's 64bytes, and adding a new item will increase it to 96 bytes IIUC. >> >> As we're using a dedicate kmem cache it might "only" add 8 bytes, not >> sure. Still an undesired increase given that we need that for each entry >> in the stable/unstable tree. > > Hm, random idea, but I wonder if we could cram a bit somewhere that > indicates whether a remap has in fact taken place? He, also what I raised elsewhere :) We would have space for that in the rmap_item. But see my other message, maybe we can indeed store the pgoff. Needs a second thought. -- Cheers, David