From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (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 BEDD524338F for ; Tue, 10 Jun 2025 17:04:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749575091; cv=none; b=uKLUUIjctYN6QL11FjJm7nYGgXChpE2vSgV/JyjcApuRmcUZXpwMuub793vYKqwKKBd4LMGE2lAPK66g+bZdPQiFB5X9fP5a+Nk7auF1Dvtv5P4N18DV+OmCGAFpiE2yT1hhlC8315ZTN7E3ej1NDbT4+iDyP7FLP6VrVrLyTeU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749575091; c=relaxed/simple; bh=HlSQboCqp0PnQ00GB+6CCKMVwWcrMXPm6kbrM95SHaA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=iDIUVsSClALjN0BME0JgPDC5gU4qB+KaPwxqJYzurBLsECrOWz6amFui+85/1fLzINHvhOfD2uSnhAqGLp4+cvN5Pe/OzAf2uRfWJMd4xdVADxYpBvpfnkMy15kwM3IHWw7YAdCjsnMlqkIaWcinqqjY70fWFN0Hl8AtlT73xAw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=SVbXxblB; arc=none smtp.client-ip=209.85.128.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SVbXxblB" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-450d64026baso35479165e9.1 for ; Tue, 10 Jun 2025 10:04:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1749575088; x=1750179888; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Fn3PhM+6LELPC5xE451c7krwbXmvn1wLfXtY2hbkuXk=; b=SVbXxblBIqyRuydR4o6N4iLjEKdt7DPra47cQfq1vzeqCO6YtnSY9iiNodN4NOBLuu S0N9Pp3Hqc5L9DMinY9MeWkxtvR8Od/plmEZboa5v+9acUFSsBeNMan8kIPlLYJ+d5xq p6LKiUiWzrOMhfnFXbVTLd/oT48awtWtsKbiTebBnvau8cBak4TuCORRHGkRbXULTi3E 7fpiv2ndhWTv23sfqQkzW8GfrgcF93rQQ3XqbtRTVFjL+oxtU9n0ErYEBRi1VNLm5+Hm 0CdR8qm6W47gVbnr42gjb0MLelGq4vR4USK1a+TEI73VqwZALIfo7xqXT7V756pdE3So BWyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749575088; x=1750179888; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Fn3PhM+6LELPC5xE451c7krwbXmvn1wLfXtY2hbkuXk=; b=Lw81+pNLETCnPFDg+sZVH0LI4dCnT7FBCArhwROlGDH/m1NP8LZDEPBb2CXhq6javk ChgCRDPEIWhJKtMxb6qNQXi72jPliNAcyNCZbTumUVGiSCIyizjvCbbIUny5pwrLgWWz WYfvBpU6N8BZXY1WZZUxum834mcLfUDLXYPel9ZIEnZ9zreuMAvtS2eCgXWRWzCsL+Pq +42HN+IrO16B0C4aNbq5rQkA5O0eehhtTUCvluJ+7+P9M4Mkt4TWKe2zIFs/qTRq9F+i kQWqczNcG6fJ24O/NkkD/wKjmetRQYco99uTs0Vk+9GHofdZC2tlizVoxMeBMwz3mhpM j5iQ== X-Gm-Message-State: AOJu0YwmnaKB8bjpRejHup8xNTfhaNweTIISJtTS0n0gvw33G7xnQFCw ehAaxoQv4e+c/eka/pnxDr8B0nZoU1LWZmRIwq2HVCqvKoIl0NeqyBVz8CW2F6TIhrV/D2plUcw QNo3I2lMx6y7R6w== X-Google-Smtp-Source: AGHT+IGuoHKyepOKuCopPSY2XL0HemV9xoMey65JxzRCECFk56/te0vuTyrZ59WQnTjaRIsbDfaWdtinm9UG+w== X-Received: from wmsr16.prod.google.com ([2002:a05:600c:8b10:b0:451:deba:e06f]) (user=jackmanb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:1552:b0:442:e03b:58a9 with SMTP id 5b1f17b1804b1-4531de836c9mr33031645e9.25.1749575088123; Tue, 10 Jun 2025 10:04:48 -0700 (PDT) Date: Tue, 10 Jun 2025 17:04:46 +0000 In-Reply-To: <20250313-asi-page-alloc-v1-0-04972e046cea@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250313-asi-page-alloc-v1-0-04972e046cea@google.com> X-Mailer: aerc 0.20.1 Message-ID: Subject: Re: [PATCH RFC 00/11] mm: ASI integration for the page allocator From: Brendan Jackman To: Brendan Jackman , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , , Andrew Morton , David Rientjes , Vlastimil Babka , David Hildenbrand Cc: , , Mike Rapoport , Junaid Shahid , Reiji Watanabe , Patrick Bellasi , Yosry Ahmed Content-Type: text/plain; charset="UTF-8" On Thu Mar 13, 2025 at 6:11 PM UTC, Brendan Jackman wrote: > .:: Patchset overview Hey all, I have been down the pagetable mines lately trying to figure out a solution to the page cache issue (the 70% FIO degradatation [0]). I've got a prototype based on the idea I discussed at LSF/MM/BPF that's slowly coming together. My hope is that as soon as I can convincingly claim with a straight face that I know how to solve that problem, I can transition from mode into being a bit more visible with development iterations... [0] https://lore.kernel.org/linux-mm/20250129144320.2675822-1-jackmanb@google.com/ In the meantime, I am still provisionally planning to make the topic of this RFC the first [PATCH] series for ASI. Obviously before I can seriously ask Andrew to merge I'll also need to establish some consensus on the x86 side, but in the meantime I think we're getting close enough to start discussing the mm code. So.. does anyone have a bit of time to look over this and see if the implementation makes sense? Is the basic idea on the right lines? Also if there's anything I can do to make that easier (is it worth rebasing?) let me know. Also, I guess I should also note my aspirational plan for the next few months, it goes... 1. Get a convincing PoC working that improves the FIO degradation. 2. Gather it into a fairly messy but at least surveyable branch and push that to Github or whatever. 3. Show that to x86 folks and hopefully (!!) get some maintainers to give a nod like "yep we want ASI and we're more or less sold that the developers know how to make it performant". 4. Turn this [RFC] into a [PATCH]. So start by trying to merge the stuff that manages the restricted address space, leaving the logic of actually _using_ it for a later series. 5. [Maybe this can be partially paralellised with 4] start a new [PATCH] series that starts adding in the x86 stuff to actually switch address spaces etc. Basically this means respinning the patches that Boris has reviewed in [1]. Since we already have the page_alloc stuff, it should be possible to start testing this code end-to-end quickly. [1] https://lore.kernel.org/linux-mm/20250110-asi-rfc-v2-v2-0-8419288bc805@google.com/ Anyone have any thoughts on that overall strategy? Cheers, Brendan