From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lf1-f45.google.com (mail-lf1-f45.google.com [209.85.167.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 79FB135E543 for ; Wed, 19 Nov 2025 13:09:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763557794; cv=none; b=d8nf8Z/HSF6ozPNj8GiYjIu4vmmnCNuxj4sk9y3aFGXH1vvavpVISr2nzIEaCoW9xUJflHnF46c1FvIwo2IacGkyi78SIouSe1yCcCtHSPeTaoLxiCaq7PWWYhAYLIT8uG0rwaWLyZZf8P4xbUPRaS5YYckZJvwfG2pnNDF81/w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763557794; c=relaxed/simple; bh=EaG85vAHTdWVSeElmg7dqvvzxpKeNrWU7qpyMrTnk2Q=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XPWw9BPwa7ggqFpx/f7XRo07qfXhC6oi4Vl4OP0ABs75fJ6ECKSLW12p8Ls1Jv3+pFfe69IzQVlHGk2cbslOtQM5N4MaEPi9bAvjE2e4hEsPPZE5QqmZXMO09zd9H3z8cT5BivmXMFQcwKbMxGTTQ7A0y9DgNRsGQe6UXLAb1tg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=lIhI8TjH; arc=none smtp.client-ip=209.85.167.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lIhI8TjH" Received: by mail-lf1-f45.google.com with SMTP id 2adb3069b0e04-5957ac0efc2so7280537e87.1 for ; Wed, 19 Nov 2025 05:09:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1763557791; x=1764162591; darn=vger.kernel.org; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=c8Xcv7L+0okxtsjikEPOcHfMR5tUDxOoJBYUzekVP4g=; b=lIhI8TjH+F/2DyxE4ICAiqYatbts+iXrWJ3eAjFSNnmVRQ3KCDgBvWmG1wDopwtLLQ c0SBXd/f+nY7AxNno0isVSOUJpl7gGTDQYp003/9oLb9jcygb0xfz7QWjtf7dARATBNS ZlezO381o0Hsfug5ml+WuBG6xpqVsc6HbhMrRiIQNAqF6GaZ3F5OL0LwrxUG7w0/sTE/ R9+mBwkO6uxFFSEEYkTntVDen1ZQ3LaD2iOZBSKGNoZXd9v8AMZ32IW372XNNXYXYCKH p/xOeWVSkdGaOQkJHToAnbEAD/TzfrMZGLlW+PhNIPNhD+tMT99cI9teg9GOE62M+G9V 4gKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763557791; x=1764162591; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=c8Xcv7L+0okxtsjikEPOcHfMR5tUDxOoJBYUzekVP4g=; b=v1i4uIywv1RawhizbmpKoqSOIQbG7rxdo3Ojx2EdGcII1uqDpAo3uz7106upLBaN+i mOoiqWuQRbpWw8lTI5W2aoXNUKMwDQSIbZRKZ+aQOU4VbAjq0irYdEwqW/+XThXtRv5X dcOcdrkDow9t7iSNgUGwI+Dq9Av22IxZekZFPIFI8P4EgBo58pLCzVXf/8ZHKSA1sRA5 hxR+Sx03tj60awN+6ZVkDYtedXZAmBPTmUNAwSLmZASds+GKvNlzCwPW648TAYlKqB6u kdB0AvhawB7amR3BYj/pSAw5L4ekWUCAF/beNLVcYhbecrqcCGvQELJzQROEcbHZMahJ AUaA== X-Forwarded-Encrypted: i=1; AJvYcCXBbuiNVVo2hfoOff9fPvTUGxQB69OFhEAGNissaPvYGxn63fRtMBlWT+buyFB6E8KAFNteOPTLnRlq9co=@vger.kernel.org X-Gm-Message-State: AOJu0YxfNAI8TGkMVNHfkCgeOtCZmDRTt95h6kZfLlTdtZDKyZeT7m0B aOQHXPCHZo5YsZg4hiIK3xyeFsnKzT3HqB7Yoez5mSX521CeCdroU2Dq X-Gm-Gg: ASbGncuG/M5SUnnedhYS7QfNa6S1Q3aLISU2tSJ6iVkjj8FAqgqvhTvQ7RV6xOujWHP TW5jXQBr2HKJu4qemSJsJfY6KzhyR0/i6DNY6UbGemETctlKas5Utna02EUhjXcu+MKj1fLH5zY O739+zgBXuJC/iL54s/UhK/PwS50j4N5DvGrRHj291IgDcKW6rxwy6UGo+WSnLJuAe6aL9UzXhT 8F5mE9ZgpQdM/+NfdOpaXg33ANmPcVWbxBOUjJitv7GC4r61itcVlfJw6MiVF7pmDKZuUS3463S cP0lr4QGLqedmrFT56nSaFfntcBBShtireOM9bKctp9oAYI+L6e8cHQfAyHtx2HV0lP1/P8lYiD k7H9Hd8KrawxFnEVhKtWsY3Hxiqq4I8eJdVjvDOSXAFFVV2j59qtDGFQgJyIsvxUbTwKoN+6Te4 dWo+2Dyl6KP1inZ3Sph4EV9TtD X-Google-Smtp-Source: AGHT+IHfrwK81dHP0yx9TSq7f7mym39HNGjUSxDJsPi5IK+SsnvtAFvMBaKAw1yCcIbphLLGGjp4Rw== X-Received: by 2002:a05:6512:1252:b0:595:8350:5824 with SMTP id 2adb3069b0e04-5960382873bmr1039341e87.7.1763557790245; Wed, 19 Nov 2025 05:09:50 -0800 (PST) Received: from grain.localdomain ([5.18.255.97]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-595803ac90dsm4722497e87.22.2025.11.19.05.09.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Nov 2025 05:09:49 -0800 (PST) Received: by grain.localdomain (Postfix, from userid 1000) id 3A2A35A0033; Wed, 19 Nov 2025 16:09:49 +0300 (MSK) Date: Wed, 19 Nov 2025 16:09:49 +0300 From: Cyrill Gorcunov To: Lorenzo Stoakes Cc: Andrei Vagin , Andrew Morton , David Hildenbrand , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , linux-mm@kvack.org, linux-kernel@vger.kernel.org, criu@lists.linux.dev Subject: Re: [PATCH 0/2] make VM_SOFTDIRTY a sticky VMA flag Message-ID: References: <1c20ec44-0775-47e0-aabb-e1cf1f38ce94@lucifer.local> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.2.14 (2025-02-20) On Mon, Nov 17, 2025 at 07:57:30PM +0000, Lorenzo Stoakes wrote: ... > > I recall correctly that initially, merging vma-s with different > > VM_SORTDIRTY bit values was not allowed. It was a bit surprising that > > this behavior was changed by Cyrill in 34228d473efe. Cyrill was an > > active CRIU contributor at the time, so we can't even blame anyone for > > breaking CRIU :). > > Well I think Cyrill is in the right here :) the problem described there - > that of hitting the max_map_count simply due to failed VM_SOFTDIRTY merges > - is very serious and clearly highlights the issue that arises from not > merging these - that is VMA fragmentation. Hi guys! Happen to miss this thread due to high message traffic, thanks for CC'ing me ;) Yeah, disability to merge VMAs due to softdirty bit has been a serious issue, so better criu to dump more (redundant) memory than apps got broken. As to this patch series, I think it is good, thanks a huge Lorenzo! Acked-by: Cyrill Gorcunov