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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hjTRzTQhrGrGXreHhtxzCPKMstH81ZqdFJXMiKKPaDbIb3cfqd/mUIbc8mHYsyvG+ l/csTpx224sNXmdPeUtQnRv+gAKk4KvRfV22L94ohNMBv5aFPnJ64j9rkmfIiyawDk m3Y553UojSQDz8Maps8tBTZWJnbrs7byvOigk6EQ= Date: Thu, 3 Sep 2026 15:46:20 +0100 From: Yeoreum Yun To: "Lorenzo Stoakes (ARM)" Cc: Yeoreum Yun , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, akpm@linux-foundation.org, david@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org, ziy@nvidia.com, baolin.wang@linux.alibaba.com, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev, kas@kernel.org Subject: Re: [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro Message-ID: References: <20260902175611.1241118-1-yeoreum.yun@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: E6C75160006 X-Stat-Signature: 13dj67ypq566fattyd6npojt1wjzr4jd X-Rspam-User: X-HE-Tag: 1788446786-700369 X-HE-Meta: U2FsdGVkX19zS5lZ9bM028EgZ8AnmGj4AQ4C3Zfr/OHIsxNgreJuHyIdIrPu3wpbGpXwgMQCWFu0BsyUw2ilNdNhSO7sqjIM2XROXeheCpj7v+QYMz6l3d/dq+RU+eeogBgCG5EYwxOWtm8pELJlto9xzFfEvcl0yxS/zlMVA8jONRbk7tWZktHNuopOXlPTUy2IGAL9czi9jhRkpsdKmZ8MV9o5fkQJMFI0lWqDRM+mWXj4AMOh2ViMcUra8nilQFb5A4l83lctS2tgFpA+ScUEDQfEDzdg6dX866WPZwamTcuU555TNT5DgdGK46h/9D/LjVB/9aoM+3ljKUXN1NRk7gtesHEy+dvrbQPnvYP4T2pfonMVLhRkj3Pj5/fAhFyijIlWDntP//hy5rqSV2tMUj8aeC+0wvtih36+cfROlB/MzSxrr7dFvVRL2q8R+pie91+mxxpbeaRfbusDu4EfnkevGReEu0xBZbQvfR2nWA5DfHZVtg6nAFAeN0JuxDZ/F48ejXbPenrqgStmokUUuQtMqX/zGJJW9yUxqu9KpGLvcV5BINarQpSsIiyE7y5IE6d6ImpJ0pKuKSAwB3IBfur6MWaa5UYDCEWsGnV1OQKInHamVkvOK8NFzJba+UaR82Xb1XXBC/tyjAlXzezCiaalcL/5n4jechCTz3dmG395nmhzyrv29k172GNsBSyqfsUQtE2f8SyGQosh2dugJckmEsIZBfzE839sDYRD53toM3YluUZaybHgaePl0CdbZvfJXPkTgl/Sraic7JggPs/FfPSnryPXRxDoUm+vhgeBAzpRzKmVaOCh9ClQAudaScEw1R1eVYCJln1QEfopxpaZNeQstiba7gfr+ZqNewxtWdAPMze52x9G5HZYzrQAe1/y4US7V9IrR28r0wG03OE51fParncja9IWs1P5kpRueRQQdxbg4/70r9GB1Z4+7MW1DqYq2VNNyAc 5ocGaIJf qqlBfxhX1A3h+/8Y101sqfPFyTDjRAvaM93hV2pu3MMPtUFDQ5BJuBK45311ssEN99Y1Wz3TXwlmiIN/aqLLGIa/FXakniupidWZrMD9WyMvUT6UmEjhIqriv3OaeLbMKhVS/F0m2f0PEWm6nMhLfDQruNqia9rTj2MG16+cj6+RzXV4q06rLPqECBLD76F4xgaA47FwfUoQ6L06Smsv9X0qWKzIdUc6SIMVc0Q6TyYA39Xhvjcq7FOSh2IHg3HLq+ikjS7AS5OdmIlJojZeTpKrG4A7CA5hYb93O Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > > On Wed, Sep 02, 2026 at 06:56:11PM +0100, Yeoreum Yun wrote: > > > HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE. > > > When this macro is used in some test, test result would be strange in > > > the system where PAGE_SIZE is more than 4KB. > > > > > > Here is example with transhuge-stress test with 16KB PAGE_SIZE: > > > > > > transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB virtual memory and 1908 MiB of ram > > > 3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 failed, 2566 different pages > > > 0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 failed, 0 different pages > > > 0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 failed, 0 different pages > > > 0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 failed, 0 different pages > > > 0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 failed, 0 different pages > > > 0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 failed, 0 different pages > > > 0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 failed, 0 different pages > > > ... > > > ok 1 Completed > > > > > > Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift() > > > helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist > > > helper, read_pmd_pagesize(). > > > > > > Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which > > > is the LCD pmd_size among 4KB, 16KB and 64KB page_size. > > > > Probably worth spelling out Least Common Denominator for those who might > > mistaken this for a kind of display panel :P > > Bad typo :( LCM (least common multiple) :( > > > > > I also wonder if it's worth pulling that out as a separate patch in a series for > > better bisectability? > > Okay. I'll separate it. Hmm, I think it would be better to keep the change as is, including the updated ksm_tests parameter. Although allocate_transhuge() correctly allocates mappings aligned to the PMD page size, `ksm_tests -H -s 100` would otherwise fail because 100 MiB is not a multiple of the PMD page size. [...] -- Sincerely, Yeoreum Yun