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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1C960F3C263 for ; Mon, 9 Mar 2026 13:43:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6B9136B00A0; Mon, 9 Mar 2026 09:43:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 69AD26B00A1; Mon, 9 Mar 2026 09:43:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 57C426B00A2; Mon, 9 Mar 2026 09:43:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 4A1F76B00A0 for ; Mon, 9 Mar 2026 09:43:23 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id E228C1A01D1 for ; Mon, 9 Mar 2026 13:43:22 +0000 (UTC) X-FDA: 84526641444.30.EC9A934 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf03.hostedemail.com (Postfix) with ESMTP id 06D2F20002 for ; Mon, 9 Mar 2026 13:43:20 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ZQb15M8r; spf=pass (imf03.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1773063801; 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=RTnKyrf0LGE23PY9A0Ht7/mKiGV1tV3urT+EyE+Hxyk=; b=4f7ZwCpcTTwyF1lHuVBQOc7hT2rlJmeUYmpqt6m+2sP5FU5KlYeEp+RsxKIis0NQ5nR1qd t/ImP0Rim0lqDjl5yaT19v8HXK5wvKHjj52k/4z44ScrZeEIystuteTQziZ47roCDjB16I egnIHJXFCiaqNS5pjVND0lMiTAj8+mA= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ZQb15M8r; spf=pass (imf03.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1773063801; a=rsa-sha256; cv=none; b=4/SI9LMuWIas4ibQoKzf7B+6GZz2MSsFbLPrsJUZnFo3WjBp3m9QecgFGfitdZ0ZIUe+0D FLRLjr6NMvXK1zZzsXrNcmXF1i/oxXWWOCtE2JbL69S/xNZA1nO41JQMuzBQReU9KUCDAF s/SrCatkiF8RuvPEgY95Cn66rJ1lI1U= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 4186543F44; Mon, 9 Mar 2026 13:43:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63895C4CEF7; Mon, 9 Mar 2026 13:43:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773063800; bh=zmy6clpWE/fIfSwygLZAhqxBM8N2z/0Tt68Uy5Q+aps=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ZQb15M8rxYvJv0UYuVy3BjBEkCLY1h9j+2RWQ//mAm3xX6WceXqnxkU4KAPcMqc47 /9Uak9k3MJ/h0TYdTUn7Ac9tQqUCeKrpXZ083Xz450GT2rMHX5TYSn7TE2OOIreeJR H5f9S7hKuWa3u3c65EUomV/LE/YU5fNB0AST+s3WVjA8ytL//jsYsWAhHNeEfeP+ei l2UdQqYswcS1+0QGd5fVBRbdvR/b9Mkk/pLCp/Y2q3Ac/2R+vM8hoE4/q69Cekjsyf LQTnL/+3sWAOkRBVihWgT/nKXVQTTI8laKUWwE8QZ5Vcnr2WkVMuaQpOqEN9j8KESl FX9xqEf2DSKyg== Message-ID: <4f2abf42-983f-4cc2-92f5-c81827e7b7e2@kernel.org> Date: Mon, 9 Mar 2026 14:43:11 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 2/4] mm: huge_memory: refactor anon_enabled_store() with change_anon_orders() To: Breno Leitao , Andrew Morton , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Mike Rapoport Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, usamaarif642@gmail.com, kas@kernel.org, kernel-team@meta.com, "Lorenzo Stoakes (Oracle)" References: <20260309-thp_logs-v4-0-926b9840083e@debian.org> <20260309-thp_logs-v4-2-926b9840083e@debian.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260309-thp_logs-v4-2-926b9840083e@debian.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 06D2F20002 X-Stat-Signature: jtm3wah64gbjxgdex6ck53z7nczcmusp X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1773063800-190585 X-HE-Meta: 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 xxaBXONQ ORR1+N+3izUMvt9r8CWvO8ViTq1KoGQg2DEaqfgDMztguJa07svfXxomVHpkFNEdNVLSVdiQ5K5ndLt5bMuaW40jgWVv3zJhJTgrK2utGvsI80kd8z6OA7f8AYYSIdDwR2e5em682sb66mfAvieQ8P6ohwlkTRm0CYdZy3pj7d3TsdYNbzLqPPoYIn2q5Rf0PGyy8Ip4rQ0VBOCusyUlk+d2q2vBBYlctvw/r9QkFmqf4MJHw5tHpZmvkVCG2IgQFMUXVzLBzAZLjf3HAn5uqwp9rq52IB84xfS6MWKdvtQeK4jKMI9rgC64eF0mAan4cKEF9H99YKiLIZLvMUx4lIuuQih9TPADXqNxA Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 3/9/26 12:07, Breno Leitao wrote: > Consolidate the repeated spin_lock/set_bit/clear_bit pattern in > anon_enabled_store() into a new change_anon_orders() helper that > loops over an orders[] array, setting the bit for the selected mode > and clearing the others. > > Introduce enum anon_enabled_mode and anon_enabled_mode_strings[] > for the per-order anon THP setting. > > Use sysfs_match_string() with the anon_enabled_mode_strings[] table > to replace the if/else chain of sysfs_streq() calls. > > The helper uses test_and_set_bit()/test_and_clear_bit() to track > whether the state actually changed, so start_stop_khugepaged() is > only called when needed. When the mode is unchanged, > set_recommended_min_free_kbytes() is called directly to preserve > the watermark recalculation behavior of the original code. > > Signed-off-by: Breno Leitao > Reviewed-by: Lorenzo Stoakes (Oracle) > --- > mm/huge_memory.c | 84 +++++++++++++++++++++++++++++++++++--------------------- > 1 file changed, 52 insertions(+), 32 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 8e2746ea74adf..2d5b05a416dab 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -316,6 +316,20 @@ static ssize_t enabled_show(struct kobject *kobj, > return sysfs_emit(buf, "%s\n", output); > } > > +enum anon_enabled_mode { > + ANON_ENABLED_ALWAYS = 0, > + ANON_ENABLED_MADVISE = 1, > + ANON_ENABLED_INHERIT = 2, > + ANON_ENABLED_NEVER = 3, > +}; > + > +static const char * const anon_enabled_mode_strings[] = { > + [ANON_ENABLED_ALWAYS] = "always", > + [ANON_ENABLED_MADVISE] = "madvise", > + [ANON_ENABLED_INHERIT] = "inherit", > + [ANON_ENABLED_NEVER] = "never", > +}; > + > static ssize_t enabled_store(struct kobject *kobj, > struct kobj_attribute *attr, > const char *buf, size_t count) > @@ -515,48 +529,54 @@ static ssize_t anon_enabled_show(struct kobject *kobj, > return sysfs_emit(buf, "%s\n", output); > } > > +static bool change_anon_orders(int order, enum anon_enabled_mode mode) I would suggest something a bit longer but clearer "set_anon_enabled_mode_for_order()" Or shorter "set_anon_enabled_mode" 1) set vs. change. the function returns whether actually something changed. 2) We're not really changing "anon_orders". Yeah, we're updating variables that are named "huge_anon_orders_XXX", but that's more an implementation detail when setting the anon_enabled mode for a specific order. > +{ > + static unsigned long *orders[] = { > + &huge_anon_orders_always, > + &huge_anon_orders_madvise, > + &huge_anon_orders_inherit, > + }; Having a "order" and "orders" variable that have different semantics is a bit confusing. Don't really have a better suggestion. "enabled_orders" ? hm. > + enum anon_enabled_mode m; > + bool changed = false; > + > + spin_lock(&huge_anon_orders_lock); > + for (m = 0; m < ARRAY_SIZE(orders); m++) { > + if (m == mode) > + changed |= !test_and_set_bit(order, orders[m]); > + else > + changed |= test_and_clear_bit(order, orders[m]); > + } Can we use the non-atomic variant here? __test_and_set_bit(). Just wondering as the lock protects concurrent modifications. > + spin_unlock(&huge_anon_orders_lock); > + > + return changed; > +} > + Apart from that LGTM. -- Cheers, David