From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 48FFD4CB22 for ; Wed, 10 Jan 2024 16:13:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="ULAwTu+k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78C52C433F1; Wed, 10 Jan 2024 16:13:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1704903218; bh=DC1KrK9zZHOGFWhnL1Oq8gaqMqREWs/jlLvYBcCVczI=; h=Date:To:From:Subject:From; b=ULAwTu+kZxO41peilyRI62vJoFQx6NVbOQtocx++p0QSK050relYAhKKmZmdK40lI Zx3tH7zscFung+U/ITKDQDI/6itpOBX4dDFusbd0qBclEE0xd3WoHdMrVMFA/h9noJ 3mBHq2/pKCkpQ1ED/4UuriIycxCUPSEY8RobH3RA= Date: Wed, 10 Jan 2024 08:13:37 -0800 To: mm-commits@vger.kernel.org,ying.huang@intel.com,willy@infradead.org,riel@surriel.com,oliver.sang@intel.com,fengwei.yin@intel.com,cl@linux.com,yang@os.amperecomputing.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-mmap-map-map_stack-to-vm_nohugepage.patch added to mm-unstable branch Message-Id: <20240110161338.78C52C433F1@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: mmap: map MAP_STACK to VM_NOHUGEPAGE has been added to the -mm mm-unstable branch. Its filename is mm-mmap-map-map_stack-to-vm_nohugepage.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mmap-map-map_stack-to-vm_nohugepage.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Yang Shi Subject: mm: mmap: map MAP_STACK to VM_NOHUGEPAGE Date: Wed, 20 Dec 2023 22:59:43 -0800 commit efa7df3e3bb5 ("mm: align larger anonymous mappings on THP boundaries") incured regression for stress-ng pthread benchmark [1]. It is because THP get allocated to pthread's stack area much more possible than before. Pthread's stack area is allocated by mmap without VM_GROWSDOWN or VM_GROWSUP flag, so kernel can't tell whether it is a stack area or not. The MAP_STACK flag is used to mark the stack area, but it is a no-op on Linux. Mapping MAP_STACK to VM_NOHUGEPAGE to prevent from allocating THP for such stack area. With this change the stack area looks like: fffd18e10000-fffd19610000 rw-p 00000000 00:00 0 Size: 8192 kB KernelPageSize: 4 kB MMUPageSize: 4 kB Rss: 12 kB Pss: 12 kB Pss_Dirty: 12 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 12 kB Referenced: 12 kB Anonymous: 12 kB KSM: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB FilePmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 0 kB THPeligible: 0 VmFlags: rd wr mr mw me ac nh The "nh" flag is set. [1] https://lore.kernel.org/linux-mm/202312192310.56367035-oliver.sang@intel.com/ Link: https://lkml.kernel.org/r/20231221065943.2803551-2-shy828301@gmail.com Signed-off-by: Yang Shi Reported-by: kernel test robot Tested-by: Oliver Sang Reviewed-by: Yin Fengwei Cc: Rik van Riel Cc: Matthew Wilcox Cc: Christopher Lameter Cc: Huang, Ying Signed-off-by: Andrew Morton --- include/linux/mman.h | 1 + 1 file changed, 1 insertion(+) --- a/include/linux/mman.h~mm-mmap-map-map_stack-to-vm_nohugepage +++ a/include/linux/mman.h @@ -156,6 +156,7 @@ calc_vm_flag_bits(unsigned long flags) return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) | + _calc_vm_trans(flags, MAP_STACK, VM_NOHUGEPAGE) | arch_calc_vm_flag_bits(flags); } _ Patches currently in -mm which might be from yang@os.amperecomputing.com are mm-mmap-no-need-to-call-khugepaged_enter_vma-for-stack.patch mm-mmap-map-map_stack-to-vm_nohugepage.patch