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b=T9zILBjJvlXqgZnbl+t/5TzLTNPaRoMdSRwbPPU3Y3krCQy9j8Sz+O0SAna9P4k+1 0HTyvWd33XIJ0VYCXB/sBt0bJ1aoWcQ5vyDIegD9H1fRbGSK5bJkgqWli3lJ7ztNsI diGsGwWTrIVseGFQcsUAabfpyxdEaFZudgcPxU8nvZYanuWQxVYnfUrikSl5nI8kP1 hYppWhY0fdZR0k7bqZaaAGzTZ6fWy3CbjShYGD1belX5Bj+kVhg9xCFNDFwA7dQgxE 6S1IRTSPPpmw7mfzQk+X9WlotxluioJw0Eli48tlYpuM3Tx9dBxyanbguNB3cMjlFR 8vesLPeAq5G+A== Date: Thu, 3 Sep 2026 15:47:58 +0100 From: "Lorenzo Stoakes (ARM)" To: Yeoreum Yun Cc: 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-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 049CBC0003 X-Stat-Signature: zy8ixym9wqco16bzcmpeihmgprpzxzxi X-HE-Tag: 1788446886-237966 X-HE-Meta: U2FsdGVkX18dGLodbNlckxV76Wbf2rp5+UnT+FpG8s1twKPWLo/XTiVcllvMWkF92MauOZag8c+ydtD540FJn3EKrfwAMM0qHNbOE9y5kftf8oxx40FRPbDrQEDnss84LS58JV0Io18rnL7vxxy+WvoQbJmlvUNsv5XdOcYVEVDdWW92K8Onf7QA3ttMBMPp47YZsU+TmF3YY1gDobMVv08c65mkzlwBSNf1V1f4oVqV24PwYFJ6kWeNDsAPvgGtYegVHphn8HQAW6Zf2XyI39cIQGJMJv34WlhNYkvBKpB7Q4PgIeO0U08pbHeZzNsAU3GNIA8Y91pyF62AeG3HIQv0KDK8BPFnjRFiLdxOOWsEI164izEAC86mXTpLBM8QSVhBKqeULUfb4PHgAdDSf2RxvavjFlfIu1Tb750XT76NP0Jhfk0Fk+kWqgzmc96adNe0cNQOYX8oiteLapu4PezTTIBRzBVDmXtLe08IJkcR2O9ZBUpGOmokBDKBfJijUoa0lZyGLKK+sO8ReYVCmgwiJK9/ddWw1Gzkpg+WxwQZ3JivDYflTJM4kgnwNRpej8psa9InMv9Q4cVFWIgLgdNsQDJ6yY1AH7Q27mdbrLxZ75MyJcYhntKKqtQFiSzsWbJLXDYbhh5eA6JAYV8nMSBP4yU56d1b97s8yxfKxDUpe5X69U08jIEnj5sXk1qvhtgh4H8eVxTKNcIYtPmPsZXpmKXY2d1JrBoi6ytc03Z6dJ2YKAO41VJDaaa2Qj13vsjLBrrtyE+uA0cKrebPzpXA7TNUKcoMRcGK+19j+HGdWU4jGQ2W8wc/s6PkcZQvAKg/m0veh0HBP9gQSrczKAAyBNOZIrfpAePLDpID0jwygWkS1QLeOIJtR0Wd4VMw/rHsNFuoy/jRGBzIUn6qLESsmTKPs14dhtLGWORI42f4OwVzUzcubxKyobB383PV8bVDZkVintL+7XWhxuK FTDxF+yp MnFEMzoAWYbbcvx3JoIVT952+BC2EOa/b9NqkyBaKoUDgNV1QwvSyjTj2pQjh7L84bIFLpLsXAthWRTX4jn/KgNPcTivxWxeBrmM/gizSDCB/MxAKiQND44/9G7yZMw9nJP3nj5nNVaUO4AIKkaU5dOFSeApw1cVPCLnw/bOBDdLN9VedYoTqYpQFW+2zLf6EGKb/pnPJdsJfbwat5zoiPtPX1/zb3S5e3bTwGYc3asNu0p2i0oW1Rab4GZo3uCPvz+8DGg35yV2UBIFQbqDkBEoyoXFRJYnQ7CU9BaUCBw6CuII= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Sep 03, 2026 at 03:46:20PM +0100, Yeoreum Yun wrote: > > > 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. OK, just add a note about it in the commit msg :) > > [...] > > -- > Sincerely, > Yeoreum Yun -- Cheers, Lorenzo