From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-124.freemail.mail.aliyun.com (out30-124.freemail.mail.aliyun.com [115.124.30.124]) (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 734C5158D88 for ; Wed, 24 Apr 2024 09:31:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713951090; cv=none; b=R+a3LjaOZwDLGJdvz1xiTV9olL89cvCzCX1+rNbPwfBYaNBtA4YQuMYh+mpBLVtIPHc05rrB609GmunCDC49KbME+2k3w9+5U0GK1YcjrC8hU7ZuHsc/GWRSTyAez7ntXUc+Su7UCaCdJnQ29a910BIS7RpbaUGwwRku2caSh0Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713951090; c=relaxed/simple; bh=8PWDdtiB3Xzzlhux/xDf8i4DGsXpZQEMjMXh021hTAc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ncRgSBNuA8NTbu4OZzUEf6K9bWEUYK1l8bZJyv2NbdcuaU5gRtrfHcBiTEY8iQ9Im0+YtV/BD0FHkSgESY6uLnJTItwZO3ke8j/7CxXGMb2Cqh3TmnTx9hsXaP96zY3VQVV0+8dS6FUGMj+eASD2MXi5+Qt3z02TPCOG3JoSGQ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=YPnyalHg; arc=none smtp.client-ip=115.124.30.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="YPnyalHg" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1713951084; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=zipW5OKTuriO6u7AdV/9p85sXllwC1SbrX531oPkRyE=; b=YPnyalHg5ucnWQMHM2GBdmUjlrWA3v5X4jxKwYvNEguosIIkXV6HWRairtvxuyjc0w4Y0cHnIg9TiTx1xfFWuCg/Dw093qQ9GN5qYa+xqIVSt9a13zFb2oGPenlRyCiaDKyZJFsOvr3DD+jspw0/s+rrIav8FjBde1zGB9cko6s= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037067111;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0W5ByeSc_1713951080; Received: from 30.97.56.58(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0W5ByeSc_1713951080) by smtp.aliyun-inc.com; Wed, 24 Apr 2024 17:31:22 +0800 Message-ID: Date: Wed, 24 Apr 2024 17:31:20 +0800 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: [RFC PATCH 5/5] mm: shmem: add anonymous share mTHP counters To: Ryan Roberts , David Hildenbrand , Barry Song <21cnbao@gmail.com> Cc: akpm@linux-foundation.org, hughd@google.com, willy@infradead.org, wangkefeng.wang@huawei.com, ying.huang@intel.com, shy828301@gmail.com, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <05d0096e4ec3e572d1d52d33a31a661321ac1551.1713755580.git.baolin.wang@linux.alibaba.com> <140d4efa-28a0-449a-9570-9d44c23b55d1@redhat.com> <5edfe6b3-8f00-46c4-8ddb-d1add845541d@arm.com> From: Baolin Wang In-Reply-To: <5edfe6b3-8f00-46c4-8ddb-d1add845541d@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2024/4/24 16:15, Ryan Roberts wrote: > On 24/04/2024 08:11, David Hildenbrand wrote: >> On 24.04.24 08:10, Baolin Wang wrote: >>> >>> >>> On 2024/4/23 19:37, David Hildenbrand wrote: >>>> On 23.04.24 03:17, Barry Song wrote: >>>>> On Mon, Apr 22, 2024 at 3:03 PM Baolin Wang >>>>> wrote: >>>>>> >>>>>> Signed-off-by: Baolin Wang >>>>>> --- >>>>>>    include/linux/huge_mm.h | 2 ++ >>>>>>    mm/huge_memory.c        | 4 ++++ >>>>>>    mm/shmem.c              | 5 ++++- >>>>>>    3 files changed, 10 insertions(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h >>>>>> index 26b6fa98d8ac..67b9c1acad31 100644 >>>>>> --- a/include/linux/huge_mm.h >>>>>> +++ b/include/linux/huge_mm.h >>>>>> @@ -270,6 +270,8 @@ enum mthp_stat_item { >>>>>>           MTHP_STAT_ANON_SWPOUT, >>>>>>           MTHP_STAT_ANON_SWPOUT_FALLBACK, >>>>>>           MTHP_STAT_ANON_SWPIN_REFAULT, >>>>>> +       MTHP_STAT_SHMEM_ANON_ALLOC, >>>>>> +       MTHP_STAT_SHMEM_ANON_ALLOC_FALLBACK, >>>>> >>>>> not quite sure about this. for 2MB pmd-mapped THP shmem, we count them >>>>> as FILE_THP. >>>>> here we are counting as SHMEM_ANON. To me, SHMEM_ANON is more correct but >>>>> it doesn't align with pmd-mapped THP. David, Ryan, what do you think? >>>> >>>> The term "anonymous share" in the patch subject is weird to begin with >>>> ;) Easy to confuse with anonymous cow-shared memory. Let's just call it >>>> "anonymous shmem", which it is under the hood. >>> >>> Sure. >>> >>>> ... regarding the question: if we add FILE_ALLOC and friends, at least >>>> initially, we wouldn't account other large pagecache folios. >>>> >>>> ... likely we should add that then as well so the counter matches the >>>> actual name? >>>> >>>> If we later realize that we need separate FILE vs. SHMEM vs. WHATEVER >>>> counters, we can always add more fine-grained counters later. Doing it >>>> consistently w.r.t. traditional THPs first sounds reasonable. >>> >>> Um, once we expose it to userspace through the sysfs interface, the >>> sysfs interface should be explicit as much as possible and avoid >>> confusing users, otherwise it will be difficult to change this kind of >>> interface in the future. Personally, I prefer to Ryan's suggestion. >> >> Inconsistency is confusing. As long as you avoid that, I don't particularly care. > > This is a good point. We have been careful to make sure the 2M ANON mTHP stats > match the existing PMD-size stats. So we should definitely make sure that any > future 2M FILE mTHP stats match too, which I guess means counting both SHMEM and > FILE events. > > So perhaps it makes more sense to add FILE counters to start with. If we need > the SHMEM-specific counters, we could add them later? > > I'm happy to go with the crowd on this... (Seems I'm the only one who prefers the term 'SHMEM_' now.) Fine, I have no strong preference, and let's keep consistency first. Thanks guys.