From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 609CAC46CCD for ; Tue, 19 Dec 2023 02:34:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EF9486B0080; Mon, 18 Dec 2023 21:34:46 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EA9356B0081; Mon, 18 Dec 2023 21:34:46 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D70C76B0083; Mon, 18 Dec 2023 21:34:46 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id C62316B0080 for ; Mon, 18 Dec 2023 21:34:46 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id A134414013C for ; Tue, 19 Dec 2023 02:34:46 +0000 (UTC) X-FDA: 81581999772.09.9C2B9CB Received: from mail-qt1-f176.google.com (mail-qt1-f176.google.com [209.85.160.176]) by imf20.hostedemail.com (Postfix) with ESMTP id 4EF4B1C0017 for ; Tue, 19 Dec 2023 02:34:43 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=bytedance.com header.s=google header.b=AJ3g+IbR; spf=pass (imf20.hostedemail.com: domain of zhangpeng.00@bytedance.com designates 209.85.160.176 as permitted sender) smtp.mailfrom=zhangpeng.00@bytedance.com; dmarc=pass (policy=quarantine) header.from=bytedance.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1702953283; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=D9QkIhhrk9atF5NzOy+uO1AzHmVd/CKbg5xM+XgezA8=; b=l3sihS6nHJvkZD0wUfgb3RsmUHqB1h54wyibUUzqmtowLNtv1mrnOjgO8213ybck7JBFhL 4w7Goh7I+S/14C0sIV7CI8x6v10mt2Pagf65fRCzq7rQ+WrVBhEdq+CxMKIUb/Nd2TZiM9 hz5B+DaNV/hikhaethC38DJW2ckwITc= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=bytedance.com header.s=google header.b=AJ3g+IbR; spf=pass (imf20.hostedemail.com: domain of zhangpeng.00@bytedance.com designates 209.85.160.176 as permitted sender) smtp.mailfrom=zhangpeng.00@bytedance.com; dmarc=pass (policy=quarantine) header.from=bytedance.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1702953284; a=rsa-sha256; cv=none; b=3NZFY5jovJHyc81Okhg2pFMz39EaiCQuPD5EHqoZ2EHtnvYbY/nQfEbYwf/mx1dQb7P4B+ EOzgpqHXZTLHok89B905H1fWs6ePN81zHn/OSWAzFH1eGvx4R2GPwDmK2abViLekRCzzqx VYCm9o5ZZJFFFlb2HIcglPhs6sFEBBg= Received: by mail-qt1-f176.google.com with SMTP id d75a77b69052e-425c6157762so37555451cf.2 for ; Mon, 18 Dec 2023 18:34:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1702953282; x=1703558082; darn=kvack.org; h=content-transfer-encoding:in-reply-to:from:cc:references:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=D9QkIhhrk9atF5NzOy+uO1AzHmVd/CKbg5xM+XgezA8=; b=AJ3g+IbRNNI92vja1tCi1g4l31LZFG40/UJQwA2MAkWHYr0Yq/IV1UVVweLMoA0Ln8 UaL4ws2FJpV0bx4F/hjL1zvcbWiKe/i5tpumzSqWzFf0bmyu8/DLaX9yOdcgHamd6AXM iihIrS+zAA2quO0JA7WeO3jmKkquPMqk07ZNM9jhE8ZO25L23gLvXogxT0VapUqJl9sq yIxkhTyugeX2JwaZfT1V5s9kM2NHmBeOBtiLpahoJNtGtufZFQ0TH73m01g9A8kEWl0x fD9EoTX9Qy3hEEWlkFJ1nx0JgelIgxaZxg0TzE0ynBVLP1aOYZDjbWDaCps05Hu6iMDE eKRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702953282; x=1703558082; h=content-transfer-encoding:in-reply-to:from:cc:references:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=D9QkIhhrk9atF5NzOy+uO1AzHmVd/CKbg5xM+XgezA8=; b=orl9qSEYKFfWtj4Pw7TFhxEwhw1EBaU2h6sc4hLTbCNfRcYL3fjX7ivJKR9nJQZQOW BYCIWgFgbD7/pOJpox2TGwQPpysYmcmVrJajsWY5z47BgVPDdcpA64fgvHYum4DReUys 0VrmqhqMoQqPS6KJ1uLlVQPfe7PqIB53p+aSv3XlWXWk6U3dxPvV3x43R3pPjGbxwKYu /9+R5Te45S/DU8iCgFbYNWRzNDae5BGZ/mjBEJfTRQSmmeNlPIEiWYVmz6xw4VC6uUHC z2URBxu3B/cd3IOZ0c0WGor2B1rBMsZo2ZoBuAqmBqM0Ccd2fFEoqE4RM4u7XLNx5hlD LF1g== X-Gm-Message-State: AOJu0Yx83H04Uz8ACTeagXvnG3TcklanqAl931HywMPmWF/HQ6rSk/Bn 0Pv25iUN4TZEcU5FKQAyCnF2zPSPfgnph1IKWgs= X-Google-Smtp-Source: AGHT+IHsFgkgz+k2eXh+Ho5A/KHaCd16u7/K+YstrOpkAJ59a8FRHMBI1Q/QtcqiaOOXoo/87BlMaw== X-Received: by 2002:ac8:5790:0:b0:425:8637:f81a with SMTP id v16-20020ac85790000000b004258637f81amr22848990qta.71.1702953282222; Mon, 18 Dec 2023 18:34:42 -0800 (PST) Received: from [10.84.146.214] ([203.208.167.146]) by smtp.gmail.com with ESMTPSA id qc12-20020a17090b288c00b0028b6f522fedsm252431pjb.43.2023.12.18.18.34.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 18 Dec 2023 18:34:41 -0800 (PST) Message-ID: <00ffc2e3-446b-473e-89b9-a859f36e43dd@bytedance.com> Date: Tue, 19 Dec 2023 10:34:36 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] maple_tree: Avoid checking other gaps after getting the largest gap To: "Liam R. Howlett" References: <20231215074632.82045-1-zhangpeng.00@bytedance.com> <20231218202014.mpotsekdkszasn4t@revolver> <20231218202845.buffbdq3vhpiv2py@revolver> Cc: maple-tree@lists.infradead.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Peng Zhang From: Peng Zhang In-Reply-To: <20231218202845.buffbdq3vhpiv2py@revolver> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 4EF4B1C0017 X-Rspam-User: X-Stat-Signature: xbk8tyf5ok4d8t95b5djm9w1sbdia9jp X-Rspamd-Server: rspam01 X-HE-Tag: 1702953283-988788 X-HE-Meta: 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 nHXLgLlH 2Qy9Zq7LMrJpl/LEpqVBVNucQPGhI+hObPOqwZ0ywYNcdvLELsh8mKhqp+7vIiPCXoZW17MDS/9Hm0VArwtQeyQjU4ckv/qvmVIYYHg7WMnggsg6qU+V4LXwqVbU3QgkjVivLZxUTUJBHXpzZmkzAAppctpbnbfq6eFV2/H+fiCm7BVc= X-Bogosity: Ham, tests=bogofilter, spamicity=0.007552, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 2023/12/19 04:28, Liam R. Howlett 写道: > * Liam R. Howlett [231218 15:20]: >> * Peng Zhang [231215 02:46]: >>> The last range stored in maple tree is typically quite large. By >>> checking if it exceeds the sum of the remaining ranges in that node, it >>> is possible to avoid checking all other gaps. >>> >>> Running the maple tree test suite in user mode almost always results in >>> a near 100% hit rate for this optimization. >> >> This should only be triggered for right-most nodes and root though, >> correct (mas->max == ULONG_MAX from just before this)? Yes, only for right-most nodes and root. >> >> I wonder if it's worth special case checking the first gap if the node >> min is 0 as well. Might be worth looking at, but this patch is >> certainly worth doing. > > Actually, not just when the min is 0, we have a special case close to > here for slot 0 so we could just check the same sort of thing there. I think that the first slot in a node does not have any special significance. It has a lower probability of being the largest gap, so it may not be worth considering. > >> >>> >>> Signed-off-by: Peng Zhang >> >> Reviewed-by: Liam R. Howlett >> >>> --- >>> lib/maple_tree.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/lib/maple_tree.c b/lib/maple_tree.c >>> index c9a970ea20dd..6f241bb38799 100644 >>> --- a/lib/maple_tree.c >>> +++ b/lib/maple_tree.c >>> @@ -1518,6 +1518,9 @@ static unsigned long mas_leaf_max_gap(struct ma_state *mas) >>> gap = ULONG_MAX - pivots[max_piv]; >>> if (gap > max_gap) >>> max_gap = gap; >>> + >>> + if (max_gap > pivots[max_piv] - mas->min) >>> + return max_gap; >>> } >>> >>> for (; i <= max_piv; i++) { >>> -- >>> 2.20.1 >>> >