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 DCCCAC47258 for ; Tue, 23 Jan 2024 06:49:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2DCA36B0081; Tue, 23 Jan 2024 01:49:23 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 28CE56B0082; Tue, 23 Jan 2024 01:49:23 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 12E2D6B0083; Tue, 23 Jan 2024 01:49:23 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 016F56B0081 for ; Tue, 23 Jan 2024 01:49:22 -0500 (EST) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 939D34062D for ; Tue, 23 Jan 2024 06:49:22 +0000 (UTC) X-FDA: 81709649364.29.3CFDACE Received: from mail-vk1-f174.google.com (mail-vk1-f174.google.com [209.85.221.174]) by imf20.hostedemail.com (Postfix) with ESMTP id CE6B11C000E for ; Tue, 23 Jan 2024 06:49:20 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="bO/nYasd"; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf20.hostedemail.com: domain of 21cnbao@gmail.com designates 209.85.221.174 as permitted sender) smtp.mailfrom=21cnbao@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1705992560; 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=umePHjAi6OPcq1K6nxeQmgi5O1MnXjNUe9aGL0eZ2Jk=; b=HzPYMcoyHDMD7UYzgyHxD/IQBxM7VjktwlKMAAvOVlRFe/Oo98xnOITLt/Th/KnoGjA84d q13H/jgcGArWGmwEvwpoAt5Z/EID18ZNjAGklSA3ed4ZrIHXyOQdTZjSVaqtJeSg/3MMUY PO3CzK8CIGrhBV+wgB0ZYWkZAMtowt4= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="bO/nYasd"; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf20.hostedemail.com: domain of 21cnbao@gmail.com designates 209.85.221.174 as permitted sender) smtp.mailfrom=21cnbao@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1705992560; a=rsa-sha256; cv=none; b=LnsN3/GjBE2H/uuclnqG5hQyiDp9vDYJ6U8a0Mcntt6WgzDy/Je8BWv0W8PQF0gvLWEdJn Csj6YdoGPSYiZUcYM61WS1GgQ2DD5selJK2O3vpWl7AybwI+Q1/LB6xgr23HPDFKwcpIh4 Eca5TilTaEn287yNxgnnPPi4VvXrYS0= Received: by mail-vk1-f174.google.com with SMTP id 71dfb90a1353d-4b72377deb0so1206228e0c.2 for ; Mon, 22 Jan 2024 22:49:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1705992560; x=1706597360; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=umePHjAi6OPcq1K6nxeQmgi5O1MnXjNUe9aGL0eZ2Jk=; b=bO/nYasdgqNWEcEnQRoH792zE4m4dD4vxzj0vJbUi3/+8nnfA6mB/5GEXTdY1572Zr keKjkjeHuWxg4uPDyMcXpNTAl3tIya3RjZNuBL1mC5G2cuJ/wUNcF7nGX/H9Rfl/w+U/ 65aBJI8U422uZ6ylOCkcXM/J0tcPleRbaTJDmSztzZH9Vvji9DgtPuDvSf28pKx8SGIw WmklCeSmCxumqO5jhlxvoZmA49g93QSY6iXgVLL/XCJz2UIC0E/NM43Y0gM2REIJaQmh 6CoONMK4NujCWyHlPoDZrl8EpCY2wnyJV9Fi9AG+Ai9zENbUQ2ZStbz+1N/ES0e2RQWF PExw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705992560; x=1706597360; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=umePHjAi6OPcq1K6nxeQmgi5O1MnXjNUe9aGL0eZ2Jk=; b=qHyffXSriHwWMkIoUU7BsqUfTpFHLQemd3YrA7wtTYapfOOA9wJWDbxpmHq5wMIoRX rIiU+aW0/ugtBIFumbT9yOOqhEs3eT5T5JR/ai1ediwQaUN99GCvk8qq2ZfbpS00U27d HCV/T6FWw4CZmFwFJg1SEZUqpG/fXw77RvldUNt/NcqFBbHsKAK0QDGznTkP+0tNSTP+ 8EoRBytjADt5bDNODFPRMLw2eRhND3BG4ChTklSwqR8mpLUZfyoEI0e4aU9LznMMKY0s ZqvWBqA5fPSWSjj0NlvmQmxEk6fKou05mlHLxvGwfzs3aMW/8EDzCJV7rNCbwjBjzLUz Jl3g== X-Gm-Message-State: AOJu0Yy9mvBoElbr0lOrFzenJIDurtlj0Cpw5yXnDcG3Hrm80pAurB8m Nz86vF5BYVhpUBtBRWNwN7KRkKGq+wFLe9PFZoya5YT8oZvGzWbD7mRlLjBW6JXggbg+kvnx4Q/ DdSzYskCGPTQ1Rvb9P56+s12atRs= X-Google-Smtp-Source: AGHT+IE2gMzDvsTBt/j6Qclci7KJi+JTAtAmsONKwyB9uLVGQi6YpN/0FchdLV+oVbhdXEzPwYtrCtI9lZqnYkgSMTI= X-Received: by 2002:a1f:4a07:0:b0:4b8:ce85:1e97 with SMTP id x7-20020a1f4a07000000b004b8ce851e97mr1885512vka.20.1705992559918; Mon, 22 Jan 2024 22:49:19 -0800 (PST) MIME-Version: 1.0 References: <20231025144546.577640-1-ryan.roberts@arm.com> <20240118111036.72641-1-21cnbao@gmail.com> <20240118111036.72641-6-21cnbao@gmail.com> <58efd8d4-28aa-45d6-b384-7463568b24bb@redhat.com> In-Reply-To: <58efd8d4-28aa-45d6-b384-7463568b24bb@redhat.com> From: Barry Song <21cnbao@gmail.com> Date: Tue, 23 Jan 2024 14:49:08 +0800 Message-ID: Subject: Re: [PATCH RFC 5/6] mm: rmap: weaken the WARN_ON in __folio_add_anon_rmap() To: David Hildenbrand Cc: ryan.roberts@arm.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.com, shy828301@gmail.com, wangkefeng.wang@huawei.com, willy@infradead.org, xiang@kernel.org, ying.huang@intel.com, yuzhao@google.com, surenb@google.com, steven.price@arm.com, Barry Song , Chuanhua Han Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Stat-Signature: 3xbbdtapw9yano1rtw9pqqp78x9pa9re X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: CE6B11C000E X-HE-Tag: 1705992560-838778 X-HE-Meta: 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 VRKSiyY8 9NyIGePLI7pe291+xylNhXAc2Vnfy/eiX/CF/U1K85Jy6iToHfGTzK4mfud4mmEXxoboqe6uvcJo1qVMEnvCYgK4xaa6/C8p0zxQf/2lXhNmDi5Bf10kHG5jbOG34fKzt1WYP0890FEVo3j4G3ci+3u92dJNBCCPS6UeTqfL0qskNCPjd+b7VJsrr0zng5xLvYd7oN6uGqBVrWV/JepCmebTPZ4hCNC8a7CeusR40QA1SrY2IK/uFFUPW00EC7LKRWjesuVb5wuDrfCfOjWYmOCxTiKRHuKRTZqjnT2NbId8SSXxpX+fMoH8+ZwR69l7buNGWAHks0NMo4RN84N9k6hfmhmtSfjqDwZqn7I6fYfUx5SRtgRus5IfXLIb7KfoLQML9cx+g0h7X2XU2LLMWSO4RCw5XNrV4Go17caNYwkh4mecV1KlNsqNhq6wA0EEd9XMtaWPYFQuO2K/FTjEzPRY4+fRcWUQ8MonMcom0kSegiJw= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jan 18, 2024 at 7:54=E2=80=AFPM David Hildenbrand wrote: > > On 18.01.24 12:10, Barry Song wrote: > > From: Barry Song > > > > In do_swap_page(), while supporting large folio swap-in, we are using t= he helper > > folio_add_anon_rmap_ptes. This is triggerring a WARN_ON in __folio_add_= anon_rmap. > > We can make the warning quiet by two ways > > 1. in do_swap_page, we call folio_add_new_anon_rmap() if we are sure th= e large > > folio is new allocated one; we call folio_add_anon_rmap_ptes() if we fi= nd the > > large folio in swapcache. > > 2. we always call folio_add_anon_rmap_ptes() in do_swap_page but weaken= the > > WARN_ON in __folio_add_anon_rmap() by letting the WARN_ON less sensitiv= e. > > > > Option 2 seems to be better for do_swap_page() as it can use unified co= de for > > all cases. > > > > Signed-off-by: Barry Song > > Tested-by: Chuanhua Han > > --- > > mm/rmap.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/mm/rmap.c b/mm/rmap.c > > index f5d43edad529..469fcfd32317 100644 > > --- a/mm/rmap.c > > +++ b/mm/rmap.c > > @@ -1304,7 +1304,10 @@ static __always_inline void __folio_add_anon_rma= p(struct folio *folio, > > * page. > > */ > > VM_WARN_ON_FOLIO(folio_test_large(folio) && > > - level !=3D RMAP_LEVEL_PMD, folio); > > + level !=3D RMAP_LEVEL_PMD && > > + (!IS_ALIGNED(address, nr_pages * PAGE_SI= ZE) || > > + (folio_test_swapcache(folio) && !IS_ALIG= NED(folio->index, nr_pages)) || > > + page !=3D &folio->page), folio); > > __folio_set_anon(folio, vma, address, > > !!(flags & RMAP_EXCLUSIVE)); > > } else if (likely(!folio_test_ksm(folio))) { > > > I have on my todo list to move all that !anon handling out of > folio_add_anon_rmap_ptes(), and instead make swapin code call add > folio_add_new_anon_rmap(), where we'll have to pass an exclusive flag > then (-> whole new folio exclusive). > > That's the cleaner approach. > one tricky thing is that sometimes it is hard to know who is the first one to add rmap and thus should call folio_add_new_anon_rmap. especially when we want to support swapin_readahead(), the one who allocated large filio might not be that one who firstly does rmap. is it an acceptable way to do the below in do_swap_page? if (!folio_test_anon(folio)) folio_add_new_anon_rmap() else folio_add_anon_rmap_ptes() > -- > Cheers, > > David / dhildenb > Thanks Barry