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b=TLM9qiFRmSC1tCtcBAePtY3fy6K0KGdplYo5ycckdrsC1+wumtfKqPccMY5GTnV85VnD+ViprJmNoFXnsrTtV1Yuwr/Dvbc8wmZyYKGrw8PEU9bQhzKpw6u5xUMj8m788l2EjWurNs8dYiMQqhVOulprtMv3xFrXgerydUBykJA= 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 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 X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 3AA2412001B X-Stat-Signature: sckz33hhu5zujjog1u4fza1ku5a7mijy X-Rspam-User: X-HE-Tag: 1713951085-88605 X-HE-Meta: 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 1bTWWcC0 k0zuSq3HfmhKdCM121YyovEcTN0QGFBWECeuXy0JIckv6w7lAizx/nOwroo8SiEsGSSMdq7Cb8eObcymudLL5Ndnjub+GcqRk84cxSZj/OpqNzZatMmPpHMIUGfM7P5IGAS0+lwgwyOCs0gXEUviHDNetq1Okuppu9+v32OVmrw0HaIW/yr+wijLCKEvJCABjNTDHcdOgbxRH80v93O8oR2ZIDXrnHNPEEZ2NowC4NvpINYnZ3YEnrJa6K2PQfliPTqXIzqYIPm5DC7V5SMsAOqD4bxuQFFZeysQ3ZurClMoY/liG4YuYELBeFXQ0F6fpeNsBdzK2NNPsqZJqUaAfWs598TZrvLA+ZqdZ X-Bogosity: Ham, tests=bogofilter, spamicity=0.000009, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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.