From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792945915; b=p573U1vfppxOs1jbx1gEG5dWV0nU7nBBdu7eUbmIv2GEwsOvF24C3f0SZQOhzz23c04J Le48OfvXDBA8E/NLQnIFx/A0P+nODoR5GCzl8bz7QQNfQavQqX4rPTQChbh0urjH12YGV YeXgDUA4+LgrwjXGG306jMouTLoa9MXdH6+RnlgxtSfgxqEbchLHHHzCBhoYcbbJ2tRcG yCEQBxNkwbG484lf/+OmQWvS0sR7tHNEGn75Lf8F1A+LIJKbneZNAqHsaRe+Zcqecmp8O jNSsmInT0eG5zyIpf/snr4o3dBcReVdjL6ZuNkc6b8qzTBboQT60OcwoKNKXaXg1/hA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792945915; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=C7hNe7rBKCu9uUEO/jwfySCAYA0VtDvIcRvVM2g0mW8=; b=HDpy1A9qY/UiuTuR4dt+d0G0Qh5/H/35haM1XqGn/ehJA6JneIoSZ0BaloBwKJGvxuf2 lMTm5d6ts/X9/zG+p8AI4ZVi33Hx+btyo5CtlCOt/XaxYMn59o+n2GFTr/bvhcJ28FDo/ YPh2HTR53ihAj9rVnI43VXqty/I+aCFp0HUY6HFkk5n6V8hg1W4nHUTM+fKammPjgvWW4 iq+pwnryUvjwo/tpl4r8e0300LOuNfeipgPeP7urH9DK6iNc96L0bW4kNMOdMANg8PmyM vwhiLKoh4lPfRX6g8cwxqoRQ+jpsN+Ea0sD0bJSBxSi3e9zKsgiv8Q+ALJJFcf0lVmg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=CVmvqT6M; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 599EB606A31A for ; Sun, 25 Oct 2026 16:31:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=CVmvqT6M Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0D401F01825; Sun, 25 Oct 2026 16:31:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792945914; bh=C7hNe7rBKCu9uUEO/jwfySCAYA0VtDvIcRvVM2g0mW8=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=CVmvqT6M9T9Yc6V2AOjJK0k4CzmV40vUgiiAOylMcv0LjUTXCo/haqBvCx6KUOMLQ prooVAUlQ50rGIwVVvpHp6DF2SRUy73P3cYGRtJz6OZg9QCHFgtm9xy9HgKUAwcO98 X+PPzvNxgg5fq1zYAFUCzHfQ2rLjc84aMSpCramH3AtIXcGqvwgayRKhyOuHX8Q9Fs afsjVLZiRbIA+YMZPDQ72nSS0r+BZN4ewVmRrcTNgGJ194vCsL5Mxs9i45m0+FgXW5 4ICFbffNWbJKRQs9rLDaJKuZyqfbLqRZEZmruvjo5DnP0pNldp1YZymr3e8YVKItm8 Jb0qJ3yPXmrog== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH] Revert "perf/aux: Allocate non-contiguous AUX pages by default" Reply-To: sashiko-reviews@lists.linux.dev To: "Leo Yan" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20261025-perf_revert_prefer_large_alloc-v1-1-5fb431bbd624@arm.com> References: <20261025-perf_revert_prefer_large_alloc-v1-1-5fb431bbd624@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 25 Oct 2026 16:31:54 +0000 X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > This reverts commit 18049c8cff9cc89daadc4df6975f7d9069638926. >=20 > The original commit claimed that contiguous AUX pages unnecessarily > exacerbate fragmentation for SPE, TRBE and ETR. This is not generally > valid: larger allocations can keep pages with the same lifetime > together, while order-0 allocations can scatter them across large > blocks and prevent free pages from coalescing [1]. The follow-up > discussion [2] has not established how forcing order-0 allocations > addresses the reported problem. >=20 > TRBE and SPE write to virtually addressed buffers. The TRBE L1 TLB > has one entry on Neoverse V2 [3] and two on Neoverse V3 [4]. Small > mappings increase translation pressure, and TTW stalls can contribute > to FIFO overflow and trace loss on TRBE. >=20 > [ ... ] > [3] https://documentation-service.arm.com/static/633fe1ec4c59b30b517730b8= #page=3D52 > [4] https://documentation-service.arm.com/static/67361bd2c7fc0d1f211da382= #page=3D54 > [5] https://lore.kernel.org/linux-mm/20260715120813.3609949-1-jiangwen6@x= iaomi.com/ >=20 > Signed-off-by: Leo Yan Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261025-perf_rever= t_prefer_large_alloc-v1-1-5fb431bbd624@arm.com?part=3D1