From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (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 C887417BD3 for ; Mon, 14 Oct 2024 23:22:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728948135; cv=none; b=CC9mYIU+qw2AaX7hxjVFZlFDZsZfVWPHziI91bKvlogoFjFR8Mhwtf5fqRPdOKWO6EFRX0yH7XP42lll6XIqYtjn4rg7bQ7juOHnnismTOeRkbPixo3pOItVle+GMlzhDncYlFKALBRzDjIB6ZfTcvaDLOcoHKvCERTWAn+LD3w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728948135; c=relaxed/simple; bh=YXFCO4bccdJ+7ry4pV8c5kyf+HA7OBNn4Yy/sBqUDuo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=RsNlRSAAE52UB2D4+fJjlDKHmE+1tQ4gdjPSpIIamvBjgIkX4gVry/j9oT4Vi9EhMvIH2VNGeenBHq20eqmzhjrv5TMCfBEYbJ0U/wV+zUWG3pnDxMjNcJdHQMpmtYx4AFbaw4F7ugXdApW19sM+FI2E5mM0gg5Yha4CnQ0Xfso= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=itOo1THQ; arc=none smtp.client-ip=209.85.215.202 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--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="itOo1THQ" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-7163489149fso4872936a12.3 for ; Mon, 14 Oct 2024 16:22:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1728948133; x=1729552933; 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=VAu7m51SVxmU1exE3wy3lzahRBBLAty9XHzwNKyTXnk=; b=itOo1THQIZKCxeEhoyZJu0ctcJbNb4NX1uJWAp+Wma3/DJgmeZF1IFtg81Cfo6w3eX jjhZXBmraENnVWOw6UlJvucRrm6Qfb26CSnKpRyAiaWb+L6o5vAME5sutUNUb++XRGsg WX6FG+JY1RQCLDK9smYLF3Zmujanv0u7NwdqqQCxtDs3BELlj5yngHB9JDfz6+Ri/ubL OpzaAelZ5dUTSK8D2LMVVIcLzVDAFW4htTH4UucXg8SxvCyinNvcApEh8J+ChQK8W64u Exxg/gBQPo1Ps3PIG3a1uHLKSGWOH1Y35zUBYt12mtCIunddRsSVZGITUODS0ypY1iVt ZQAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728948133; x=1729552933; 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=VAu7m51SVxmU1exE3wy3lzahRBBLAty9XHzwNKyTXnk=; b=joWNP7oRMzBr3HA2O4Sa0xU4xP4+sMlqu2gXKoLOlBU/feOGoyy4p7A9rNqvs4jYN7 23PqUQUccsSuZIlX1e2fb+7c4AdhIoD3OuMVODl03zlXCAfJpzrHszOUOCUFtKS8YBcp u09JumBq6EytHZB8wJvDAsdp9MyOeNAQw3A8v4Vy3zsA4zNIbAPJCtwCGvGPdqfn2+xb hhsyocUYgAqO6GVXl20JurWZxTK5tATPWEHpt7RxXv2+sgUOvKPPW43ZV+NfWfRzQjj6 zr0WEvA2kCP9HugzZb5U1cFFLgAHsKqupQP5OiEKVlHr8iP38eebmnb4vi7+XT1V+5ps LmRw== X-Forwarded-Encrypted: i=1; AJvYcCX0LeqBcHKj0vv+E3oa+WAI/yikzmHi9kqox6m1knIwRJrge18U2aH8+BmUf1gYdMLi6akk+Lny0Ks=@vger.kernel.org X-Gm-Message-State: AOJu0YwCsM0bVaiiD9sV/M3mBJuAm7Tl7sOT7S8nE50cYUR/CgUJ2Ad/ //RhaZ9as4gdanA4yBkvQjfln5k2QJa4Hulr9TEfwU++sXewqNN6Y0Op9XZDhyIv0CatJyF8YEA OsQ== X-Google-Smtp-Source: AGHT+IEKOSgRz9DiX0LTECtalJA9o5kHyI4bzVItB0t5QtRGcyAmOXJ+lxLiO/PhBoXndkle9dQfPQy7mvE= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:9d:3983:ac13:c240]) (user=seanjc job=sendgmr) by 2002:a63:c25:0:b0:694:4311:6eb4 with SMTP id 41be03b00d2f7-7ea5358e4e2mr17001a12.8.1728948132929; Mon, 14 Oct 2024 16:22:12 -0700 (PDT) Date: Mon, 14 Oct 2024 16:22:11 -0700 In-Reply-To: <20240926013506.860253-1-jthoughton@google.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240926013506.860253-1-jthoughton@google.com> Message-ID: Subject: Re: [PATCH v7 00/18] mm: multi-gen LRU: Walk secondary MMU page tables while aging From: Sean Christopherson To: James Houghton Cc: Paolo Bonzini , Andrew Morton , David Matlack , David Rientjes , Jason Gunthorpe , Jonathan Corbet , Marc Zyngier , Oliver Upton , Wei Xu , Yu Zhao , Axel Rasmussen , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="us-ascii" On Thu, Sep 26, 2024, James Houghton wrote: > This patchset makes it possible for MGLRU to consult secondary MMUs > while doing aging, not just during eviction. This allows for more > accurate reclaim decisions, which is especially important for proactive > reclaim. ... > James Houghton (14): > KVM: Remove kvm_handle_hva_range helper functions > KVM: Add lockless memslot walk to KVM > KVM: x86/mmu: Factor out spte atomic bit clearing routine > KVM: x86/mmu: Relax locking for kvm_test_age_gfn and kvm_age_gfn > KVM: x86/mmu: Rearrange kvm_{test_,}age_gfn > KVM: x86/mmu: Only check gfn age in shadow MMU if > indirect_shadow_pages > 0 > mm: Add missing mmu_notifier_clear_young for !MMU_NOTIFIER > mm: Add has_fast_aging to struct mmu_notifier > mm: Add fast_only bool to test_young and clear_young MMU notifiers Per offline discussions, there's a non-zero chance that fast_only won't be needed, because it may be preferable to incorporate secondary MMUs into MGLRU, even if they don't support "fast" aging. What's the status on that front? Even if the status is "TBD", it'd be very helpful to let others know, so that they don't spend time reviewing code that might be completely thrown away. > KVM: Pass fast_only to kvm_{test_,}age_gfn > KVM: x86/mmu: Locklessly harvest access information from shadow MMU > KVM: x86/mmu: Enable has_fast_aging > mm: multi-gen LRU: Have secondary MMUs participate in aging > KVM: selftests: Add multi-gen LRU aging to access_tracking_perf_test > > Sean Christopherson (4): > KVM: x86/mmu: Refactor low level rmap helpers to prep for walking w/o > mmu_lock > KVM: x86/mmu: Add infrastructure to allow walking rmaps outside of > mmu_lock > KVM: x86/mmu: Add support for lockless walks of rmap SPTEs > KVM: x86/mmu: Support rmap walks without holding mmu_lock when aging > gfns