From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-186.mta1.migadu.com (out-186.mta1.migadu.com [95.215.58.186]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8ABA41E260D for ; Thu, 11 Sep 2025 02:39:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.186 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757558347; cv=none; b=sGxIQUYcyWoLTMQnL90M5GvkfGXWEeQ8DqBeMQDmDpqB5sf8ckQwOi3bN1pzMX2/+SfDsuhJvcPvC7RQ7aCoUev2ztrLqsFc+LHsQ7Mp+QLU90a88lOWz8GXHAMnYcRT48u/IZpIrBvix36/CFUn/BMl3jQACrdEqbp1CwBvggA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757558347; c=relaxed/simple; bh=PFvtNKguubhIfWjSjC6Fb/MczM4GGfIa3uYB6ppTtv0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QQQ7UmzUpSuvIpnNFIgvPbA/LbY+EgBkcDwpUVGSs7gcN4x35iV257MKj51ARdDA56qGGYnUUccKZXSq6ELnO2soBY+StzxkBEqQc/sN3kiuHDUbFodaoYBagYv/bFQNWv1btWb04AltyTLlQIwLjQ8mG6BHsPO4QJhkdoj2vCQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=HwUiZZ57; arc=none smtp.client-ip=95.215.58.186 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="HwUiZZ57" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1757558343; 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=e9PPyv7+boNGUzzOupoHa1DOIH/TVj7FBAqrgegDDTk=; b=HwUiZZ57ysrOi/yC8M8PEPM+a14G6LPukDNNBb/FpNvZAeOa4OnZOQRwi++L8v57aklnVP 1mK7E+u3sr8fTszO/Jkkv2bbrq7uWUD/4vaAgRN9UoY5++oQACtNvOK6McSq5DscH6HyfU O4287UNc+udxnHUrbXtrALhrZNFyB6I= Date: Thu, 11 Sep 2025 10:38:45 +0800 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v7 mm-new 01/10] mm: thp: remove disabled task from khugepaged_mm_slot Content-Language: en-US To: Zi Yan Cc: Yafang Shao , llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, bpf@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, Lance Yang , akpm@linux-foundation.org, gutierrez.asier@huawei-partners.com, rientjes@google.com, andrii@kernel.org, david@redhat.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, ameryhung@gmail.com, ryan.roberts@arm.com, lorenzo.stoakes@oracle.com, usamaarif642@gmail.com, willy@infradead.org, corbet@lwn.net, npache@redhat.com, dev.jain@arm.com, 21cnbao@gmail.com, shakeel.butt@linux.dev, ast@kernel.org, daniel@iogearbox.net, hannes@cmpxchg.org, kernel test robot References: <20250910024447.64788-2-laoar.shao@gmail.com> <202509110109.PSgSHb31-lkp@intel.com> <49b70945-7483-4af1-95ba-e128eb9f6d7e@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Lance Yang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2025/9/11 10:28, Zi Yan wrote: > On 10 Sep 2025, at 22:12, Lance Yang wrote: > >> Hi Yafang, >> >> On 2025/9/11 01:27, kernel test robot wrote: >>> Hi Yafang, >>> >>> kernel test robot noticed the following build errors: >>> >>> [auto build test ERROR on akpm-mm/mm-everything] >>> >>> url: https://github.com/intel-lab-lkp/linux/commits/Yafang-Shao/mm-thp-remove-disabled-task-from-khugepaged_mm_slot/20250910-144850 >>> base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything >>> patch link: https://lore.kernel.org/r/20250910024447.64788-2-laoar.shao%40gmail.com >>> patch subject: [PATCH v7 mm-new 01/10] mm: thp: remove disabled task from khugepaged_mm_slot >>> config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20250911/202509110109.PSgSHb31-lkp@intel.com/config) >>> compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261) >>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250911/202509110109.PSgSHb31-lkp@intel.com/reproduce) >>> >>> If you fix the issue in a separate patch/commit (i.e. not just a new version of >>> the same patch/commit), kindly add following tags >>> | Reported-by: kernel test robot >>> | Closes: https://lore.kernel.org/oe-kbuild-all/202509110109.PSgSHb31-lkp@intel.com/ >>> >>> All errors (new ones prefixed by >>): >>> >>>>> kernel/sys.c:2500:6: error: call to undeclared function 'hugepage_pmd_enabled'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] >>> 2500 | hugepage_pmd_enabled()) >>> | ^ >>>>> kernel/sys.c:2501:3: error: call to undeclared function '__khugepaged_enter'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] >>> 2501 | __khugepaged_enter(mm); >>> | ^ >>> 2 errors generated. >> >> Oops, seems like hugepage_pmd_enabled() and __khugepaged_enter() are only >> available when CONFIG_TRANSPARENT_HUGEPAGE is enabled ;) >> >>> >>> >>> vim +/hugepage_pmd_enabled +2500 kernel/sys.c >>> >>> 2471 >>> 2472 static int prctl_set_thp_disable(bool thp_disable, unsigned long flags, >>> 2473 unsigned long arg4, unsigned long arg5) >>> 2474 { >>> 2475 struct mm_struct *mm = current->mm; >>> 2476 >>> 2477 if (arg4 || arg5) >>> 2478 return -EINVAL; >>> 2479 >>> 2480 /* Flags are only allowed when disabling. */ >>> 2481 if ((!thp_disable && flags) || (flags & ~PR_THP_DISABLE_EXCEPT_ADVISED)) >>> 2482 return -EINVAL; >>> 2483 if (mmap_write_lock_killable(current->mm)) >>> 2484 return -EINTR; >>> 2485 if (thp_disable) { >>> 2486 if (flags & PR_THP_DISABLE_EXCEPT_ADVISED) { >>> 2487 mm_flags_clear(MMF_DISABLE_THP_COMPLETELY, mm); >>> 2488 mm_flags_set(MMF_DISABLE_THP_EXCEPT_ADVISED, mm); >>> 2489 } else { >>> 2490 mm_flags_set(MMF_DISABLE_THP_COMPLETELY, mm); >>> 2491 mm_flags_clear(MMF_DISABLE_THP_EXCEPT_ADVISED, mm); >>> 2492 } >>> 2493 } else { >>> 2494 mm_flags_clear(MMF_DISABLE_THP_COMPLETELY, mm); >>> 2495 mm_flags_clear(MMF_DISABLE_THP_EXCEPT_ADVISED, mm); >>> 2496 } >>> 2497 >>> 2498 if (!mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm) && >>> 2499 !mm_flags_test(MMF_VM_HUGEPAGE, mm) && >>>> 2500 hugepage_pmd_enabled()) >>>> 2501 __khugepaged_enter(mm); >>> 2502 mmap_write_unlock(current->mm); >>> 2503 return 0; >>> 2504 } >>> 2505 >> >> So, let's wrap the new logic in an #ifdef CONFIG_TRANSPARENT_HUGEPAGE block. >> >> diff --git a/kernel/sys.c b/kernel/sys.c >> index a1c1e8007f2d..c8600e017933 100644 >> --- a/kernel/sys.c >> +++ b/kernel/sys.c >> @@ -2495,10 +2495,13 @@ static int prctl_set_thp_disable(bool thp_disable, unsigned long flags, >> mm_flags_clear(MMF_DISABLE_THP_EXCEPT_ADVISED, mm); >> } >> >> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE >> if (!mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm) && >> !mm_flags_test(MMF_VM_HUGEPAGE, mm) && >> hugepage_pmd_enabled()) >> __khugepaged_enter(mm); >> +#endif >> + >> mmap_write_unlock(current->mm); >> return 0; >> } > > Or in the header file, > > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > ... > #else > bool hugepage_pmd_enabled() > { > return false; > } > > int __khugepaged_enter(struct mm_struct *mm) > { > return 0; > } > #endif Nice. That's a much better approach.