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 3A938C79FBD for ; Wed, 9 Sep 2026 17:39:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2DB1F6B009B; Wed, 9 Sep 2026 13:39:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 28CBE6B009D; Wed, 9 Sep 2026 13:39:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 17BD66B009E; Wed, 9 Sep 2026 13:39:33 -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 E396D6B009B for ; Wed, 9 Sep 2026 13:39:32 -0400 (EDT) Received: from smtpin24.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 56D371A02CF for ; Wed, 9 Sep 2026 17:39:32 +0000 (UTC) X-FDA: 85194935784.24.37FF7F0 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf30.hostedemail.com (Postfix) with ESMTP id 788A08000F for ; Wed, 9 Sep 2026 17:39:30 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=MD1sgUCp; spf=pass (imf30.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=1788975570; 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=lckkvQ96etQRK/jiBHaJOZl8yzGvIy0G7bi8kXAAjKE=; b=KBWcETdk64y9xM3x/U8Qx7Zc7n8+dm9e1ZXYsqKuE6HemBLZ4fiNbGVFkcJ0oH3KUhGktd 4wpbNMYPkHPC1pV8en55va1bNaUGfVzQVkOZSxss9qGP5r4cetXDnpwRnbtZ8XtaiiBzrn BJ00bvODQwWraA/WPnRkcaN95AVbtDo= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788975570; b=hLO3STWFZmFGFNXq6Jt4enSU9DhWxWxuUvYpAlvdQO5T2D7xMifNjlmWBhYAM6VdqvOHOO JdA1DBuXKs34K/bVFMM8PjOuPc8QWzQPk5FB7hgJ00GdlUL7TT15uoH0No5CRGZkBIO/ZP hC+pKa10FKPRw4qpxx77qIDbJQAjLwk= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=MD1sgUCp; spf=pass (imf30.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 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 92F5040357; Wed, 9 Sep 2026 17:39:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 528591F000FF; Wed, 9 Sep 2026 17:39:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788975569; bh=lckkvQ96etQRK/jiBHaJOZl8yzGvIy0G7bi8kXAAjKE=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=MD1sgUCp7ahRANqwb9B3UoldMvPtufo5A6BpPQYcYs/ujUC6lNKBpgfTf5cncrxx+ M7FZaCSNNmJLs6zuogEfmbn/2Tf5sbkMkvfeMEElL4soC4xOiyUU67o0inDM/ffssf mUtENC1EA/a8YRubyznqR+NQhKXWUItgYr3KK+hTSQ2S3LPewGll3v/F20ErJaOAd5 53hbLnDjPCFl0h69kxMTQO9kEI0PjYkcH7TZ2Etjcc0q7axb1ilAEkydilez/s93cz 2WTEfJvfPU/1wFekPc94lQVAU9ym0sYYPTX5HSWyjI/2tCJtJq6eeVFGSXHL8Tveo7 vBGtc/2uJj5/w== Message-ID: Date: Wed, 9 Sep 2026 19:39:19 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 06/17] mm/huge_memory: consolidate irq and locking for folio split To: kasong@tencent.com, linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Andrew Morton , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Chris Li , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , Yeoreum Yun , "Kiryl Shutsemau (Meta)" , Shivam Kalra , Kairui Song References: <20260908-swap-thp-cleanup-v4-0-b532a3f20e71@tencent.com> <20260908-swap-thp-cleanup-v4-6-b532a3f20e71@tencent.com> 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: <20260908-swap-thp-cleanup-v4-6-b532a3f20e71@tencent.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspam-User: X-Stat-Signature: n4ufeqxrf5boqy86dh5mfi4uwuqgua14 X-Rspamd-Queue-Id: 788A08000F X-HE-Tag: 1788975570-934798 X-HE-Meta: U2FsdGVkX18xw6GTsTSxVrsYQ8MhVSucIoQBwPffJzL+6Lt+4nihnCzPLGCeSvb4GVZvWWCbVvr7TF3f9LAzPKRwqaWpJn1ubjU87/ZinPk9M16VGGeOLxVGresJk+cZhtLtU4sJOC/pLA2AWB6jjguEcBp0FnFzRkQRtpdzoUA+XT4S0hSw6susgbAH5ZWaAYkM2IUHhpSxYAAk5BKV7wCFhG6XLmyCldNUAhqGXDSeaIVfb98DGQfyIkTYkZDvY891dtcodH+1F4KuzmSgI5ZE8inmuv2zaer4sqDUE1QHkoumPYS93vdeK0sBcs59XQzwDEv2wrcFEBVgpOGi7ZKkJjQnPFDxIOyp8Xp/HJOg3QxKZ3vz7x43BW06l0ygOk4Hhp6Bdus1h5pPWy84aKinJTMlZGEb0ESevueIFQYBXDkHrBZhATSh8UV+2KucNFvXvbN67b1lPnd6mH3ACtJU8VKuVAfK4akldy0ZkUBx9B/74Q3dNrDi6oTwPIJHp2sPQo6oZgu/D01ex+INSgN/GOi8STS+R68pHjPyEjVVR8ZA+VTa/+9tYN/axOjd36ZOGrf6i6xXiroFooW/5miJBbyatbQMe/IuENJ1khefWfW8JNDwicJtBXzFra0hiLXYWzXSLvJyTzTVREV/+3PFxb22IUlRzl1Nkey9qbe6DCM+NiKZGt8rH0CkkgVeBGNzECxOr5om/I/5k5mSnA00pfrXQdNfFY829Y+JV3kFlIHpoj+spSdEi572IGzRxMgKn84ctlqLew6d5drygG25Abfc0oOncVujTCd65JGzI7wGakDOj8vEmF9T006kAmG73NVuvsL3C+n/xbgGcBY/mV6Nry6oPTBoPAjLXcHSHHSA+QSwXOzhc33CmGqwAVgE1MyVKxq5plJeS/0pZu8zQdeM4V+VQWtnVyT7f7dUW7F81vn3ekAuSlp2Dfz81Ep3ulGb26xPjz+PDbx iPzbW0Hq w36FEnGAHYP1V7UdX1BRPeWN8EbfNB2fWWDqnV/wGY1+xSK1n46aZfhTpGhYsuJUX19LnuuDRSPDQ4Mb44rKneLLPepj5ifToBNM4I+Sv+qddEoRffohxEdys2wZY0v27qbcZUyhkepleH8ednMW3NgNrZJzZ0JFZl6OG4mHvSy6LkQvmabAvwAjB6XcLOpfENfTr/7cnyXYqNZ3MW11RWkJCniFXatV0KmLctnALtjYL0AJ58L2cMKfgkeuvq1oOo3rfxwaQQ6kqCwNioio/v0XpeAL8vekbeAWM6gqU7bHahyLurDiAoUuhPlVIBHti9nuILdy4N0qviGVJNlPlUlPPSZXDCpKokkiSOJpO2STWJknrgS4ap6TPe7gUzXplIhQzjUeq9rE8ukw7PiIXLepYBuRLVtF99L5IModf32Jd7nKeZwxm/x9SLA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/7/26 20:12, Kairui Song via B4 Relay wrote: > From: Kairui Song > > Let each split helper handle its own locking instead of relying on > the caller, so both helpers manage their own irq and locking state. > This lets __folio_split() drop its local irq handling and fail label, > preparing for further cleanup. > > The file path now uses xas_lock_irq() instead of local_irq_disable() > with xas_lock(). The two are equivalent on non-RT, and > TRANSPARENT_HUGEPAGE cannot be enabled on RT anyway. This conversion > also buys consistency: every other place in mm/ that freezes a folio > while it is still reachable through the page cache already takes the > lock this way. This was actually the last plain xas_lock() on > mapping->i_pages left in mm. If we are going to support RT, spinning > on frozen folio refs could be a problem, but it already exists in > many places and should be fixed generically. > > The anon helper keeps a single local_irq_disable() as before, because > it has to cover several plain spinlocks at once. > > The dropped xas_reset() was a no-op as the xa_state is not walked > before the xas_load() under the lock. > > Reviewed-by: Zi Yan > Reviewed-by: Kiryl Shutsemau (Meta) > Reviewed-by: Yeoreum Yun > Signed-off-by: Kairui Song > --- [...] > if (nr_shmem_dropped) > shmem_uncharge(mapping->host, nr_shmem_dropped); > @@ -4390,8 +4391,6 @@ static int __folio_split(struct folio *folio, unsigned int new_order, > */ > int folio_split_unmapped(struct folio *folio, unsigned int new_order) > { > - int ret = 0; > - > VM_WARN_ON_ONCE_FOLIO(folio_mapped(folio), folio); > VM_WARN_ON_ONCE_FOLIO(!folio_test_locked(folio), folio); > VM_WARN_ON_ONCE_FOLIO(!folio_test_large(folio), folio); > @@ -4400,11 +4399,8 @@ int folio_split_unmapped(struct folio *folio, unsigned int new_order) > if (folio_expected_ref_count(folio) != folio_ref_count(folio) - 1) > return -EAGAIN; > > - local_irq_disable(); > - ret = __folio_freeze_split_anon(folio, new_order, &folio->page, > - false, NULL, SPLIT_TYPE_UNIFORM); > - local_irq_enable(); > - return ret; > + return __folio_freeze_split_anon(folio, new_order, &folio->page, > + false, NULL, SPLIT_TYPE_UNIFORM); Yeah, that bit looks especially nice. Acked-by: David Hildenbrand (Arm) -- Cheers, David