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 44E9BC021B1 for ; Thu, 20 Feb 2025 20:37:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C71E14401E6; Thu, 20 Feb 2025 15:37:46 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B31404401D8; Thu, 20 Feb 2025 15:37:46 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 985264401E6; Thu, 20 Feb 2025 15:37:46 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 7DC094401D8 for ; Thu, 20 Feb 2025 15:37:46 -0500 (EST) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id C732E1CD035 for ; Thu, 20 Feb 2025 20:37:45 +0000 (UTC) X-FDA: 83141484090.13.613711B Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf04.hostedemail.com (Postfix) with ESMTP id 7E07D40003 for ; Thu, 20 Feb 2025 20:37:42 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Iq9bgnhx; spf=pass (imf04.hostedemail.com: domain of luizcap@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=luizcap@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1740083862; 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=8t4gQ1JMFD1FIhHE3k4ie/A6wJVY2Cs3xyygQZCuQmk=; b=tYDIphzdvoQLGd61gcc3WfR0Y3TJEftXtc7wwmWb+xx2oEy3KYa3f4DtkhRbNHqjq5Dgdo vuya8vagBD2XmUadlqWFL8tNh1HGg7FyU1Xl/K/cY+yMUJnWxg5hWw/UasZRYUAmMfsir5 Yu5mKIWQU0zKjLzSIUwBd4MnNHilrqQ= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Iq9bgnhx; spf=pass (imf04.hostedemail.com: domain of luizcap@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=luizcap@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1740083862; a=rsa-sha256; cv=none; b=4743sqU3yuXGl+hxQ4j3QeRkNFFOg0LbivLUg7NS68ewX84KQXQAvZKBA4m9PZWG9UIDj7 vKcFGlos8XyMi28ObZew3XvXBpl+s9rKe/PyfA6EqIv5x0k+N4xAVpeBJfQPx2UWYqFhGn YPueOprI3s1xBi6clD4Oi3ENFjbT0zs= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1740083861; h=from:from: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; bh=8t4gQ1JMFD1FIhHE3k4ie/A6wJVY2Cs3xyygQZCuQmk=; b=Iq9bgnhxOF+UxqsmmmX3bA3h9J3aS9rXJm7pmryZaWRb80/VCzxu109IaNLKbGd//i4j8+ 4bpPpT+8txYz84EKkWE0xEaIoG+VXkoiESLWCL/CW3SzAWk7pP273tP3fqXsPJhcNyS4fL +hgfnjEzz71Z9AKPMf8JWMKuU29BCWA= Received: from mail-qk1-f198.google.com (mail-qk1-f198.google.com [209.85.222.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-625-Fb_Yf5M-O9q59Y0XntyF3A-1; Thu, 20 Feb 2025 15:37:38 -0500 X-MC-Unique: Fb_Yf5M-O9q59Y0XntyF3A-1 X-Mimecast-MFC-AGG-ID: Fb_Yf5M-O9q59Y0XntyF3A_1740083858 Received: by mail-qk1-f198.google.com with SMTP id af79cd13be357-7c0a71aaf61so207170285a.2 for ; Thu, 20 Feb 2025 12:37:38 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740083858; x=1740688658; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=8t4gQ1JMFD1FIhHE3k4ie/A6wJVY2Cs3xyygQZCuQmk=; b=DuK+zcqK5S3xO8wISjuUzupjMpO/C2SWYwJlg7G7oPnlnCFKj2qT/rDwkveEmelNCM Rpi07eX3w5gmiYI0eBLJlvZiFI7+MXu5G4S3OyuuVTZ8sZaz+pxz8ZRIjwMGxsHxCTj5 KUA1+yI72ucIpdADM5IKqZMNTJdreLtT/wsDePlBsBEVugPithXchaDWeJkFt6L2IJkt FmwYtS7D8RHbVigopypmRsXk6596UqBXLUCo2nrxxShKgUrZgPnPxDKvueOU4bzBePyj RR6JtqpOISBBpxptwF9ZVJYmyOTSJw4Galt3+zJ2EM8v7aZu7Rtx1BdGwcm+mdgXjjrl dHFw== X-Forwarded-Encrypted: i=1; AJvYcCXbCQ5Hfobbr4U+nMUouF9Gk4SIitpTj2rOt6K7Y/pRivhLsKTa+/HINo7myYxLIQ7HXlOqMse9jg==@kvack.org X-Gm-Message-State: AOJu0YxfrLoWTQmzdOijYu4LJjiNYTVjnAo9Tw75XKBPaCiDqrhYUZ9/ nCvGLqVejeRQt2f0YbqghGzrqkCPugYQrnu9OK/QssGGAfoRxXYQ8PTeura0GkIDug+6qDpYj0S CLdblGyx0/tz8iVMD+ksVRgYOChinaa4PBVvHUO3phkBX96XW X-Gm-Gg: ASbGncvBu1M5AY6CrCdt/ThCeIqozPrYx1DOhgIjDVSLrukiPrdZy2hRvi2kskS8Bzw 4pQxJ3Ly/O214U2DLI1IL5Q+75mQxpAlRL7QMwVHdtloDK1JejehvAn943aWWNYylyFvkgABXMO 2mvtkX9qGMn2o6EUVSDrSq2Z0WXM9gbJkL1YOuQzV3CxS409NzPm462Uht/6Xnu61jpWIXmFJic hU2oKkag9H3hQkj+XTZDVArIPWw5dtwH2rJs6WcRQL1Gom/h/G9262ux2ssbjKDDc6/u6wKKKSZ YnZf X-Received: by 2002:a05:620a:1b94:b0:7c0:c7c7:5b08 with SMTP id af79cd13be357-7c0cf8aee9bmr41207585a.5.1740083858218; Thu, 20 Feb 2025 12:37:38 -0800 (PST) X-Google-Smtp-Source: AGHT+IGQnPB9fIqgx7TSd4yBAmNnmM+SXL1P3mBIPVdAnB4Bp74kZ5q41R7E3sPDOBIl20xeYuY8gQ== X-Received: by 2002:a05:620a:1b94:b0:7c0:c7c7:5b08 with SMTP id af79cd13be357-7c0cf8aee9bmr41203985a.5.1740083857850; Thu, 20 Feb 2025 12:37:37 -0800 (PST) Received: from [192.168.2.110] ([70.52.22.87]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6e65d9f3458sm89316446d6.92.2025.02.20.12.37.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 20 Feb 2025 12:37:37 -0800 (PST) Message-ID: <45f945af-d1f4-4509-841b-1199288d12c0@redhat.com> Date: Thu, 20 Feb 2025 15:37:26 -0500 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/4] mm: page_table_check: use new iteration API To: David Hildenbrand , linux-kernel@vger.kernel.org, linux-mm@kvack.org, yuzhao@google.com, pasha.tatashin@soleen.com Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, muchun.song@linux.dev References: <85f11743d259d5e4a1f47456fbcda82ff6db9ab3.1739931468.git.luizcap@redhat.com> From: Luiz Capitulino In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: Ror5N4faQLhXEtlvgcX7Ekr3jlHXPJ8HP86GI0GmQSk_1740083858 X-Mimecast-Originator: redhat.com Content-Language: en-US, en-CA Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspam-User: X-Stat-Signature: aajyd51mmet3nuoxqj9fhz85w3pg3jpj X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 7E07D40003 X-HE-Tag: 1740083862-751875 X-HE-Meta: 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 GHuBDXUe /j9/xJ1CQd+aTbWXmqT3YfqL6lf60AJjEbJJL3nKsEDZNL+ZwwpLSCr9Oo1c4tr8qIJ7wTJHWdlLiTMGAT2AGEDv0evGt4ZbPOe6DvgXZIUAz347yAneHYtJHpYMoJFENdmWkz/lQdCC+B/Ejv8o6S4tcf2cPQ4JvlAyP5dkWnTV+gF7U2/0zIRqZLyUHzGJ/yFQrJuHpeppgJpT/apLhcV//sYBrM6kA66aUN2PntPq7PHW3P356NSqRi+Q5dRKhSJyeVz6IBze3O8fmmkyKnfot4N40eCqTJzyh8lh6oXKA/B/4cfOGJag0eRKT/RNiBE6tPyO+kJmjPupe4FIYs6VR99J8EemZa5zP6eTEBn/FJp90kIqxP4Zfhkjfqo9wj9ViQY8zHEZy4GDL2WyyV9kKr2IAeU434z3/YEeXXZzOM5ON3TwPji4b903qtPLp9AVRRzAXV7cN6IAm0tWvEf+Y/kmnLjbMqpIa X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, 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 2025-02-20 06:05, David Hildenbrand wrote: > On 19.02.25 03:17, Luiz Capitulino wrote: >> The page_ext_next() function assumes that page extension objects for a >> page order allocation always reside in the same memory section, which >> may not be true and could lead to crashes. Use the new page_ext >> iteration API instead. >> >> Fixes: cf54f310d0d3 ("mm/hugetlb: use __GFP_COMP for gigantic folios") >> Signed-off-by: Luiz Capitulino >> --- >>   mm/page_table_check.c | 39 ++++++++++++--------------------------- >>   1 file changed, 12 insertions(+), 27 deletions(-) >> >> diff --git a/mm/page_table_check.c b/mm/page_table_check.c >> index 509c6ef8de400..b52e04d31c809 100644 >> --- a/mm/page_table_check.c >> +++ b/mm/page_table_check.c >> @@ -62,24 +62,20 @@ static struct page_table_check *get_page_table_check(struct page_ext *page_ext) >>    */ >>   static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt) >>   { >> +    struct page_ext_iter iter; >>       struct page_ext *page_ext; >>       struct page *page; >> -    unsigned long i; >>       bool anon; >>       if (!pfn_valid(pfn)) >>           return; >>       page = pfn_to_page(pfn); >> -    page_ext = page_ext_get(page); >> - >> -    if (!page_ext) >> -        return; >> - >>       BUG_ON(PageSlab(page)); >>       anon = PageAnon(page); >> -    for (i = 0; i < pgcnt; i++) { >> +    rcu_read_lock(); >> +    for_each_page_ext(page, pgcnt, page_ext, iter) { >>           struct page_table_check *ptc = get_page_table_check(page_ext); >>           if (anon) { >> @@ -89,9 +85,8 @@ static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt) >>               BUG_ON(atomic_read(&ptc->anon_map_count)); >>               BUG_ON(atomic_dec_return(&ptc->file_map_count) < 0); >>           } >> -        page_ext = page_ext_next(page_ext); >>       } >> -    page_ext_put(page_ext); >> +    rcu_read_unlock(); >>   } > > [...] > >>   /* >> @@ -140,24 +130,19 @@ static void page_table_check_set(unsigned long pfn, unsigned long pgcnt, >>    */ >>   void __page_table_check_zero(struct page *page, unsigned int order) >>   { >> +    struct page_ext_iter iter; >>       struct page_ext *page_ext; >> -    unsigned long i; >>       BUG_ON(PageSlab(page)); >> -    page_ext = page_ext_get(page); >> - >> -    if (!page_ext) >> -        return; >> - >> -    for (i = 0; i < (1ul << order); i++) { >> +    rcu_read_lock(); >> +    for_each_page_ext_order(page, order, page_ext, iter) { > > I would avoid introducing for_each_page_ext_order() and just pass "1 << order" as the page count. OK, I'll drop it. > >>           struct page_table_check *ptc = get_page_table_check(page_ext); >>           BUG_ON(atomic_read(&ptc->anon_map_count)); >>           BUG_ON(atomic_read(&ptc->file_map_count)); >> -        page_ext = page_ext_next(page_ext); >>       } >> -    page_ext_put(page_ext); >> +    rcu_read_unlock(); >>   } >>   void __page_table_check_pte_clear(struct mm_struct *mm, pte_t pte) > > Apart from that, this looks very nice to me > > Acked-by: David Hildenbrand >