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X-CSE-ConnectionGUID: gmDw5uI1RSytd0v1sO1b7A== X-CSE-MsgGUID: zN6an6+TSuuDOybGO6Ngwg== X-IronPort-AV: E=McAfee;i="6600,9927,11025"; a="10415502" X-IronPort-AV: E=Sophos;i="6.07,158,1708416000"; d="scan'208";a="10415502" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2024 01:23:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,158,1708416000"; d="scan'208";a="39333337" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2024 01:22:59 -0700 From: "Huang, Ying" To: Baolin Wang Cc: , , , , , <21cnbao@gmail.com>, , , Subject: Re: [PATCH 2/2] mm: support multi-size THP numa balancing In-Reply-To: (Baolin Wang's message of "Wed, 27 Mar 2024 16:09:23 +0800") References: <87cyrgo2ez.fsf@yhuang6-desk2.ccr.corp.intel.com> Date: Wed, 27 Mar 2024 16:21:06 +0800 Message-ID: <87edbwm6fh.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Queue-Id: 550FC4000E X-Rspam-User: X-Stat-Signature: 5ap439pztgfbxdn7mjkn7adnydquyhfd X-Rspamd-Server: rspam03 X-HE-Tag: 1711527783-287089 X-HE-Meta: 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 SpGj3r4R RTe1sATc1qaMCgxvSoD2LePPpLSSqmd9h1WRANEPKUSnEeH5tfHy/Ovxb/tWpS8m2U9QrSBKQUdSYMEVXi0aomDLxKy4Vp3KHWmFrFY8FuhUF5MgAgDkIaLcmufNrRGwYEwivwQRNOHWNyvXVwj47jJBoXzv/sxjXYGSnvYbc943TXEI= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Baolin Wang writes: > On 2024/3/27 10:04, Huang, Ying wrote: >> Baolin Wang writes: >> >>> Now the anonymous page allocation already supports multi-size THP (mTHP), >>> but the numa balancing still prohibits mTHP migration even though it is an >>> exclusive mapping, which is unreasonable. >>> >>> Allow scanning mTHP: >>> Commit 859d4adc3415 ("mm: numa: do not trap faults on shared data section >>> pages") skips shared CoW pages' NUMA page migration to avoid shared data >>> segment migration. In addition, commit 80d47f5de5e3 ("mm: don't try to >>> NUMA-migrate COW pages that have other uses") change to use page_count() >>> to avoid GUP pages migration, that will also skip the mTHP numa scaning. >>> Theoretically, we can use folio_maybe_dma_pinned() to detect the GUP >>> issue, although there is still a GUP race, the issue seems to have been >>> resolved by commit 80d47f5de5e3. Meanwhile, use the folio_likely_mapped_shared() >>> to skip shared CoW pages though this is not a precise sharers count. To >>> check if the folio is shared, ideally we want to make sure every page is >>> mapped to the same process, but doing that seems expensive and using >>> the estimated mapcount seems can work when running autonuma benchmark. >> Because now we can deal with shared mTHP, it appears even possible >> to >> remove folio_likely_mapped_shared() check? > > IMO, the issue solved by commit 859d4adc3415 is about shared CoW > mapping, and I prefer to measure it in another patch:) I mean we can deal with shared mTHP (by multiple threads or multiple processes) with this patch. Right? [snip] -- Best Regards, Huang, Ying