From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 60005372661 for ; Tue, 28 Jul 2026 06:12:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785219177; cv=none; b=Pe02kCkMfwundJVz68C12kFZSfxLAFDiKKjbKtkoYxksvM6symeTCFZoNIX7tuyNgTo9x6+2VP9eEAvZrnxMV/zCtDy7KwchSe1X4E8gkNOJSgrVmYqeGYi9NKqu5FJOkdJR9d/g7IX9JnU5/zPVqgCBKOrCh4+U66h9V0z+Qiw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785219177; c=relaxed/simple; bh=b91PzJAS6m3d0mLPBuksaYLOMk2xknc8mZLXVjVh+Pw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=GJz4NYXdhctyD8aMgOXIMKUW6unnKuppe9OedhinE3m7gWzJyEHX9E7wGcQnNVsXNnKW00YOs9uLAhI2VKscJNtUEhAZjpkNUROhDDAmTfYHQaR8wUrIZm2h4lveAEvmwSIcyAT5ULa13MIzTfnCY9dYHltquTFzw6GCBWmRakc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=r3gkHQC3; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="r3gkHQC3" 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 9442C1BF7; Mon, 27 Jul 2026 23:12:50 -0700 (PDT) Received: from [10.164.19.51] (unknown [10.164.19.51]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 96AB93F66F; Mon, 27 Jul 2026 23:12:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785219174; bh=b91PzJAS6m3d0mLPBuksaYLOMk2xknc8mZLXVjVh+Pw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=r3gkHQC3Rxd7tUgANOXWNow4vrs8PU2NFSD1divGBytcs7mGWL5XFgs6hO+aAkFoq ffd2LJ37v+2zJ+aqOrOJEvAytJobm0HzKIiQv9RDoH8n11IjjAZeXIBzZZHKo4WrPr GUnj7JNp23tKlOonf8AkxkceG13kBBrP5Hpm8vLI= Message-ID: <65e0aa09-cad8-4898-abc0-a8115ae43976@arm.com> Date: Tue, 28 Jul 2026 11:42:47 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/khugepaged: replace mutex_lock/mutex_unlock usage with guard macro To: Jakov Novak , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , David Hildenbrand , Lorenzo Stoakes Cc: Zi Yan , Baolin Wang , "\\ Liam R . Howlett \\" , Nico Pache , Ryan Roberts , Barry Song , Lance Yang , Usama Arif , linux-kernel-mentees@lists.linux.dev, Shuah Khan References: <20260727181136.2542-1-jakovnovak30@gmail.com> Content-Language: en-US From: Dev Jain In-Reply-To: <20260727181136.2542-1-jakovnovak30@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 27/07/26 11:41 pm, Jakov Novak wrote: > Currently, khugepaged locks the khugepaged_mutex in two functions: > start_stop_khugepaged and khugepaged_min_free_kbytes_update. Remove > mutex_lock/mutex_unlock usage in these functions and replace it with the > guard macro. This makes the code more readable (removing a goto statement) > and makes it harder to introduce bugs in the future. > No functional changes introduced. > > Signed-off-by: Jakov Novak > --- Thanks. Reviewed-by: Dev Jain > mm/khugepaged.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 617bca76db49..c583867f2e7a 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -3113,7 +3113,7 @@ int start_stop_khugepaged(void) > { > int err = 0; > > - mutex_lock(&khugepaged_mutex); > + guard(mutex)(&khugepaged_mutex); > if (hugepage_enabled()) { > if (!khugepaged_thread) > khugepaged_thread = kthread_run(khugepaged, NULL, > @@ -3122,7 +3122,7 @@ int start_stop_khugepaged(void) > pr_err("khugepaged: kthread_run(khugepaged) failed\n"); > err = PTR_ERR(khugepaged_thread); > khugepaged_thread = NULL; > - goto fail; > + return err; > } > > if (!list_empty(&khugepaged_scan.mm_head)) > @@ -3132,17 +3132,14 @@ int start_stop_khugepaged(void) > khugepaged_thread = NULL; > } > set_recommended_min_free_kbytes(); > -fail: > - mutex_unlock(&khugepaged_mutex); > return err; > } > > void khugepaged_min_free_kbytes_update(void) > { > - mutex_lock(&khugepaged_mutex); > + guard(mutex)(&khugepaged_mutex); > if (hugepage_enabled() && khugepaged_thread) > set_recommended_min_free_kbytes(); > - mutex_unlock(&khugepaged_mutex); > } > > bool current_is_khugepaged(void)