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 9FCDFC98321 for ; Fri, 25 Sep 2026 12:10:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 96BF36B0092; Fri, 25 Sep 2026 08:10:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 944046B0093; Fri, 25 Sep 2026 08:10:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 85A1B6B0095; Fri, 25 Sep 2026 08:10:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 62D896B0092 for ; Fri, 25 Sep 2026 08:10:53 -0400 (EDT) Received: from smtpin13.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id DE25C805E1 for ; Fri, 25 Sep 2026 12:10:52 +0000 (UTC) X-FDA: 85252168344.13.A9E51C9 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf04.hostedemail.com (Postfix) with ESMTP id D214E4000D for ; Fri, 25 Sep 2026 12:10:50 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=Er6Bps5u; spf=pass (imf04.hostedemail.com: domain of sarthak.sharma@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=sarthak.sharma@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790338251; 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=Mg3HEQa8NIKTXdpXPGnm06+R+w4VsRqksh/FZxtXdKQ=; b=MXywqUS7MGhdqYfDpyH78ao3LTBiCT1v50cEG6ShqBwzpg3g2PqWShC25PXq7FqW3oLgxj f04oCpbEVVn0WOsnD6Xj6DTjFE2MCIaqyvKNdmYfwLmQhPP35aH92RGwmMPqA+oSNPfJfQ Y+XRu+dpthDB1X7Sy+qZ9mFArn+mDCE= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=Er6Bps5u; spf=pass (imf04.hostedemail.com: domain of sarthak.sharma@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=sarthak.sharma@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790338251; b=q0xUmJSB6HHebG/+WWWNWcXB7l6DnilpebVQiW31/2vJzFiOrjPDMsdnR5ZHmP6ZV1k0vl 8C2CAR72oHJyJby6kTQ/nTOrdn+u80p+pmKCSly0z+DbadzbMFa1JGI+bV0hriIpqI2GEb QDSSD0fDujTcYiQDJ5Jcp9+/LbOljAs= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 44A1D1688; Fri, 25 Sep 2026 05:10:46 -0700 (PDT) Received: from [10.164.19.84] (a081061.arm.com [10.164.19.84]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3E67F3F86C; Fri, 25 Sep 2026 05:10:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790338249; bh=NEYUebGz1uDI7Npr1A5moQGPlxhm/IrhMht840u7NQc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Er6Bps5u28i6dwAxosn/pPKCYRMfwt73pA1zVb2TfE6fj8cf/A5kmRyUPZv2+ciQ2 j1TBYB48z5UXdNCINevu8QF8PkZUhtuiQ5Pn2Ro5HP7OJI2hN54ESlSYvVJvlz7uGi wFpSLMRb/mEw4Rs/Nt2uP+2z8wwx6+vbNNgTL11g= Message-ID: <07f94688-55ed-407a-a11a-78a4feedf5e2@arm.com> Date: Fri, 25 Sep 2026 17:40:41 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 1/4] kselftest: mm: prevent random failure of huge page split for khugepaged To: Yeoreum Yun , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Kevin Brodsky Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260924-fix_split-v8-0-cba7359d882a@arm.com> <20260924-fix_split-v8-1-cba7359d882a@arm.com> Content-Language: en-US From: Sarthak Sharma In-Reply-To: <20260924-fix_split-v8-1-cba7359d882a@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: D214E4000D X-Rspam-User: X-Stat-Signature: 8zmrky1znztu1fr4cttwanoj3apb3pbs X-HE-Tag: 1790338250-993646 X-HE-Meta: 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 RHQ1wNx8 rcWCuW3tRHrH1ESNnBki3fZ9tTC4A8xPchPsck7HYtN+P33ujDYQ/5vQxJNddqlmW+LMgQRC+qWKixie7K2jd6VZF7CpmRP52XWV8pFekI+eH5fjFDTxfwmDsRUyievc+jhGFczI3904wqD01sszUDFgJLa/mNxHD57Tn1Z1RyMnCGuub6vxd8uwUPAswW7ZOvdM/lnckVQ8XJsQKRjrmA1ixCRxyGb8FRB93U4EAnwq/HQWRWC1TVxozl7ZuAc7UF7/zTj/+gnsJb+zeXJ7q07UU3joDWuVWZDVpMX2YwV0p2NK1LwPSsEuyPEVxaQMeEKNtF1ziliXB8jkoYwUrPUgYjg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/25/26 12:41 AM, Yeoreum Yun wrote: > There're some random failure for split_huge_page_test when khugepaged > collapses pages into pmd again which had split by the test. > > Prevent the khugepaged's collapses for split page by setting the > mapped pmd-huge-page with MADV_NOHUGEPAGE before split. > > Suggested-by: Kevin Brodsky > Suggested-by: Lorenzo Stoakes (ARM) > Reviewed-by: Lorenzo Stoakes (ARM) > Reviewed-by: Zi Yan > Acked-by: David Hildenbrand (Arm) > Signed-off-by: Yeoreum Yun > --- > tools/testing/selftests/mm/split_huge_page_test.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c > index c5d96a4b1db3..ef4058662b91 100644 > --- a/tools/testing/selftests/mm/split_huge_page_test.c > +++ b/tools/testing/selftests/mm/split_huge_page_test.c > @@ -108,6 +108,18 @@ static char *allocate_zero_filled_hugepage(size_t len) > return result; > } > > +static void disable_khugepaged(void *addr, size_t len) > +{ > + /* > + * Disables khugepaged from collapsing THPs in range, existing THP Should it be "collapsing pages in range into THPs" instead? > + * pages remain. > + */ > + if (!madvise(addr, len, MADV_NOHUGEPAGE)) > + return; > + > + ksft_exit_fail_msg("MADV_NOHUGEPAGE failed, err=%d\n", errno); I feel a ksft_exit_fail_perror() would be better here, since it will automatically print strerror(errno) as well. Still, it is not something that should require a respin of its own, so if you plan to respin for some other changes, you might fold these changes in as well. Rest looks good, so: Reviewed-by: Sarthak Sharma > +} > + > static void verify_rss_anon_split_huge_page_all_zeroes(char *one_page, int nr_hpages, size_t len) > { > unsigned long rss_anon_before, rss_anon_after; > @@ -120,6 +132,8 @@ static void verify_rss_anon_split_huge_page_all_zeroes(char *one_page, int nr_hp > if (!rss_anon_before) > ksft_exit_fail_msg("No RssAnon is allocated before split\n"); > > + disable_khugepaged(one_page, len); > + > /* split all THPs */ > write_debugfs(PID_FMT, getpid(), (uint64_t)one_page, > (uint64_t)one_page + len, 0); > @@ -167,6 +181,8 @@ static void split_pmd_thp_to_order(int order) > if (!check_huge_anon(one_page, 4 * pmd_pagesize, 4, pmd_pagesize)) > ksft_exit_fail_msg("No THP is allocated\n"); > > + disable_khugepaged(one_page, len); > + > /* split all THPs */ > write_debugfs(PID_FMT, getpid(), (uint64_t)one_page, > (uint64_t)one_page + len, order); > @@ -215,6 +231,8 @@ static void split_pte_mapped_thp(void) > goto out; > } > > + disable_khugepaged(thp_area, thp_area_size); > + > /* > * To challenge spitting code, we will mremap a single page of each > * THP (page[i] of thp[i]) in the thp_area into page_area. This will > @@ -482,6 +500,7 @@ static int create_pagecache_thp_and_fd(const char *testfile, size_t fd_size, > ksft_test_result_skip("Pagecache folio split skipped\n"); > return -2; > } > + disable_khugepaged(*addr, fd_size); > return 0; > err_out_close: > close(*fd); >