From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A751F1D90CD for ; Tue, 11 Feb 2025 09:48:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739267312; cv=none; b=OV+KLW9G2HVldt5xm7zvrUstg4Qw+/eHXj3DFCFBRZSJkZFMNZ5aOzMnZQtp6CGxKLIfmoShLEp787zIm7pmnC37QId/9kw0SS9OdrHmuMx5cDQcjZj5zgVXEOZSWLKzPcx60rn4X3b2NkvIc2QRF9cpTLXtzh64r1YEDuu5lQA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739267312; c=relaxed/simple; bh=QvgMQzt8/3wXGrb4tA+C4lqzexDo/BFNeLBYG30dC5A=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=VyLwOZYt49YZ6gfO6ERi7/l3qAIweWotZOLsfvptAubCHqgmHb95zT4TaZ7S/4WxgBSXSuv3Hz2HWDgy7z21aVBJIEcoyiV+m2GZ7/4DP2ES0aefWxLKWBKtZ29WLKmLrnE4W4+K31GKYlZ2ubEHya3ckVZfncmDgwDOo0hO9IA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ft49Yrf/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ft49Yrf/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A96AC4CEDD; Tue, 11 Feb 2025 09:48:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739267312; bh=QvgMQzt8/3wXGrb4tA+C4lqzexDo/BFNeLBYG30dC5A=; h=Subject:To:Cc:From:Date:From; b=ft49Yrf/ImgBBBZo/s7jpMaVkel5v5Hd8XJzbzpHgS8mvPuxj8lz0yydmpj2dZiGX eK26VgFnpJ4huzaT666e4vcBScywhUJj36gjtGsx7yqmp7GZlYlqi2slWfFL1phCiH pmZcQirkcOMB12i+cZm+zFEUBbxUYGekHz8UHWn8= Subject: FAILED: patch "[PATCH] maple_tree: simplify split calculation" failed to apply to 6.1-stable tree To: richard.weiyang@gmail.com,Liam.Howlett@Oracle.com,akpm@linux-foundation.org,lorenzo.stoakes@oracle.com,sidhartha.kumar@oracle.com,stable@vger.kernel.org Cc: From: Date: Tue, 11 Feb 2025 10:48:28 +0100 Message-ID: <2025021128-repeater-percolate-6131@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 4f6a6bed0bfef4b966f076f33eb4f5547226056a # git commit -s git send-email --to '' --in-reply-to '2025021128-repeater-percolate-6131@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 4f6a6bed0bfef4b966f076f33eb4f5547226056a Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Wed, 13 Nov 2024 03:16:14 +0000 Subject: [PATCH] maple_tree: simplify split calculation Patch series "simplify split calculation", v3. This patch (of 3): The current calculation for splitting nodes tries to enforce a minimum span on the leaf nodes. This code is complex and never worked correctly to begin with, due to the min value being passed as 0 for all leaves. The calculation should just split the data as equally as possible between the new nodes. Note that b_end will be one more than the data, so the left side is still favoured in the calculation. The current code may also lead to a deficient node by not leaving enough data for the right side of the split. This issue is also addressed with the split calculation change. [Liam.Howlett@Oracle.com: rephrase the change log] Link: https://lkml.kernel.org/r/20241113031616.10530-1-richard.weiyang@gmail.com Link: https://lkml.kernel.org/r/20241113031616.10530-2-richard.weiyang@gmail.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Wei Yang Reviewed-by: Liam R. Howlett Cc: Sidhartha Kumar Cc: Lorenzo Stoakes Cc: Signed-off-by: Andrew Morton diff --git a/lib/maple_tree.c b/lib/maple_tree.c index fe7f9e1f5bbb..ca8ae1e1cc0a 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -1863,11 +1863,11 @@ static inline int mab_no_null_split(struct maple_big_node *b_node, * Return: The first split location. The middle split is set in @mid_split. */ static inline int mab_calc_split(struct ma_state *mas, - struct maple_big_node *bn, unsigned char *mid_split, unsigned long min) + struct maple_big_node *bn, unsigned char *mid_split) { unsigned char b_end = bn->b_end; int split = b_end / 2; /* Assume equal split. */ - unsigned char slot_min, slot_count = mt_slots[bn->type]; + unsigned char slot_count = mt_slots[bn->type]; /* * To support gap tracking, all NULL entries are kept together and a node cannot @@ -1900,18 +1900,7 @@ static inline int mab_calc_split(struct ma_state *mas, split = b_end / 3; *mid_split = split * 2; } else { - slot_min = mt_min_slots[bn->type]; - *mid_split = 0; - /* - * Avoid having a range less than the slot count unless it - * causes one node to be deficient. - * NOTE: mt_min_slots is 1 based, b_end and split are zero. - */ - while ((split < slot_count - 1) && - ((bn->pivot[split] - min) < slot_count - 1) && - (b_end - split > slot_min)) - split++; } /* Avoid ending a node on a NULL entry */ @@ -2377,7 +2366,7 @@ static inline struct maple_enode static inline unsigned char mas_mab_to_node(struct ma_state *mas, struct maple_big_node *b_node, struct maple_enode **left, struct maple_enode **right, struct maple_enode **middle, - unsigned char *mid_split, unsigned long min) + unsigned char *mid_split) { unsigned char split = 0; unsigned char slot_count = mt_slots[b_node->type]; @@ -2390,7 +2379,7 @@ static inline unsigned char mas_mab_to_node(struct ma_state *mas, if (b_node->b_end < slot_count) { split = b_node->b_end; } else { - split = mab_calc_split(mas, b_node, mid_split, min); + split = mab_calc_split(mas, b_node, mid_split); *right = mas_new_ma_node(mas, b_node); } @@ -2877,7 +2866,7 @@ static void mas_spanning_rebalance(struct ma_state *mas, mast->bn->b_end--; mast->bn->type = mte_node_type(mast->orig_l->node); split = mas_mab_to_node(mas, mast->bn, &left, &right, &middle, - &mid_split, mast->orig_l->min); + &mid_split); mast_set_split_parents(mast, left, middle, right, split, mid_split); mast_cp_to_nodes(mast, left, middle, right, split, mid_split); @@ -3365,7 +3354,7 @@ static void mas_split(struct ma_state *mas, struct maple_big_node *b_node) if (mas_push_data(mas, height, &mast, false)) break; - split = mab_calc_split(mas, b_node, &mid_split, prev_l_mas.min); + split = mab_calc_split(mas, b_node, &mid_split); mast_split_data(&mast, mas, split); /* * Usually correct, mab_mas_cp in the above call overwrites