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b=Bot4zvaC3VKoQCkLVxiMMW57UXfYBtgw0ff/qIvN9YUd5PizoNdJ2lOXAB7I+Eq5P GeQGgKlAh/CUAujvoR5vWMknR84HktdPw+yWM+Np72+1j9pSpEGXwR4ftwFU684A+T b66lWoDIiNsxQfM+n+7c034mIxqKRz/I3iw86yAtC9ovWh/obpnQkojQRyH/YM5M0U vIgBpuqbmjAtcNyC2bXLyWchPWAa8ypelg+YehL5g/sha5YZrTXacEr2ej8490a5/g du51+Rr54b/fwdu7okY3/2IC833rg6+rmcv21mpD+JypUnekAoqv6F7/HF+sqNnLqe c/tNK2R8Np7lA== Message-ID: Date: Thu, 22 Jan 2026 23:20:37 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 6/9] selftests/mm: introduce helper to read every page To: Kevin Brodsky , linux-mm@kvack.org, linux-kselftest@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Andrew Morton , Dev Jain , Lorenzo Stoakes , Mark Brown , Ryan Roberts , Shuah Khan References: <20260122170224.4056513-1-kevin.brodsky@arm.com> <20260122170224.4056513-7-kevin.brodsky@arm.com> From: "David Hildenbrand (Red Hat)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAa2VybmVsLm9yZz7CwY0EEwEIADcWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCaKYhwAIbAwUJJlgIpAILCQQVCgkIAhYCAh4FAheAAAoJEE3eEPcA/4Naa5EP/3a1 9sgS9m7oiR0uenlj+C6kkIKlpWKRfGH/WvtFaHr/y06TKnWn6cMOZzJQ+8S39GOteyCCGADh 6ceBx1KPf6/AvMktnGETDTqZ0N9roR4/aEPSMt8kHu/GKR3gtPwzfosX2NgqXNmA7ErU4puf zica1DAmTvx44LOYjvBV24JQG99bZ5Bm2gTDjGXV15/X159CpS6Tc2e3KvYfnfRvezD+alhF XIym8OvvGMeo97BCHpX88pHVIfBg2g2JogR6f0PAJtHGYz6M/9YMxyUShJfo0Df1SOMAbU1Q Op0Ij4PlFCC64rovjH38ly0xfRZH37DZs6kP0jOj4QdExdaXcTILKJFIB3wWXWsqLbtJVgjR YhOrPokd6mDA3gAque7481KkpKM4JraOEELg8pF6eRb3KcAwPRekvf/nYVIbOVyT9lXD5mJn IZUY0LwZsFN0YhGhQJ8xronZy0A59faGBMuVnVb3oy2S0fO1y/r53IeUDTF1wCYF+fM5zo14 5L8mE1GsDJ7FNLj5eSDu/qdZIKqzfY0/l0SAUAAt5yYYejKuii4kfTyLDF/j4LyYZD1QzxLC MjQl36IEcmDTMznLf0/JvCHlxTYZsF0OjWWj1ATRMk41/Q+PX07XQlRCRcE13a8neEz3F6we 08oWh2DnC4AXKbP+kuD9ZP6+5+x1H1zEzsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCgh Cj/CA/lc/LMthqQ773gauB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseB fDXHA6m4B3mUTWo13nid0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts 6TZ+IrPOwT1hfB4WNC+X2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiu Qmt3yqrmN63V9wzaPhC+xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKB Tccu2AXJXWAE1Xjh6GOC8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvF FFyAS0Nk1q/7EChPcbRbhJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh 2YmnmLRTro6eZ/qYwWkCu8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRk F3TwgucpyPtcpmQtTkWSgDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0L LH63+BrrHasfJzxKXzqgrW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4v q7oFCPsOgwARAQABwsF8BBgBCAAmAhsMFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAmic2qsF CSZYCKEACgkQTd4Q9wD/g1oq0xAAsAnw/OmsERdtdwRfAMpC74/++2wh9RvVQ0x8xXvoGJwZ rk0Jmck1ABIM//5sWDo7eDHk1uEcc95pbP9XGU6ZgeiQeh06+0vRYILwDk8Q/y06TrTb1n4n 7FRwyskKU1UWnNW86lvWUJuGPABXjrkfL41RJttSJHF3M1C0u2BnM5VnDuPFQKzhRRktBMK4 GkWBvXlsHFhn8Ev0xvPE/G99RAg9ufNAxyq2lSzbUIwrY918KHlziBKwNyLoPn9kgHD3hRBa Yakz87WKUZd17ZnPMZiXriCWZxwPx7zs6cSAqcfcVucmdPiIlyG1K/HIk2LX63T6oO2Libzz 7/0i4+oIpvpK2X6zZ2cu0k2uNcEYm2xAb+xGmqwnPnHX/ac8lJEyzH3lh+pt2slI4VcPNnz+ vzYeBAS1S+VJc1pcJr3l7PRSQ4bv5sObZvezRdqEFB4tUIfSbDdEBCCvvEMBgoisDB8ceYxO cFAM8nBWrEmNU2vvIGJzjJ/NVYYIY0TgOc5bS9wh6jKHL2+chrfDW5neLJjY2x3snF8q7U9G EIbBfNHDlOV8SyhEjtX0DyKxQKioTYPOHcW9gdV5fhSz5tEv+ipqt4kIgWqBgzK8ePtDTqRM qZq457g1/SXSoSQi4jN+gsneqvlTJdzaEu1bJP0iv6ViVf15+qHuY5iojCz8fa0= In-Reply-To: <20260122170224.4056513-7-kevin.brodsky@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: B1B4420007 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: bkeco6mn7bgr9hy3my4sbcyz8txupe1y X-HE-Tag: 1769120443-48043 X-HE-Meta: U2FsdGVkX1/YlmWwPNZervrk83MjxH2errhy7a3uwEwMCTeWYHnjUcjyF+P3LLVrwogbn4npXzP8Pby+U+ukOR/3g84sd0KVAHdktP6s8SRfn7Ggi9YJktiBAOvE2nCr/4nzYWXhLSf4eF1AA/xMf+OV08CrSOdT4jFCfXCs1Rp2ioVDRr/5SqMlzD0dw/q9qoKNxPE3mhpft3hcA0JGr5huicu5nr8WJ7Dqk6vWH3aoQ/WG8ioyUnSC7aOyow/Ord876tTF/wZupA+9hFRmvnsbgjz/Y5GZgGstSiNHINshPhs4S+IsJQIHnkxY/peAlempkmQaqocjLXsVZ1qaurXsX9kUSBz19DiedDrJ1M51QMhGSbeeX5GV19ujd+9yAHYtYThMrHpocKfbW55mBZ7KhoOvyXhOKmuEHtkTHuToSY6NhnS4wYGmMFRSBXcY180dguU9qYChbZj4+mAaLb2URHUkum1oKqY2wzlsNZQ4IOyd+yofrAW898zQDQxQorYVndxWUxvr4Ox1ZcuDbru05RhsLG6BA4kwcfeISfx05My74Pti9HcTtp6lJD18MCxJ3RGbg3BBFl5OSGlfCGTpkkLGowzH08SC/5iF/SoFVGw8RW1/IPpQUABPFN/Kp79P5vp9B/dzd7X3maEHig1kstYQeKqA5E3dSv0AcCwBjpWBR4XaGjT+HCAGZvrqrxGEQJtTDm/VlyW6p+k+eYjKXTi2aiLZKWqFaQFpr3J51AYdou5D6UXskse+kSA4Jkn8WKJIGVcTyTFnhDtBFeV7ygQlht78MBOGSSOYmSJ+jvNIRskHnQkm2VJ1SZRqD0dzS/wQgdpoxqtlPA5p5slTYus/muAek/4NgCqJt0bgWJSHX6l5ABnoZI+aoHkdWv4suIN99voSRXBUJ+4p/IHoer0Zp8JO32E7bgEyA6tzGfcuY0NfMTDBc+NbrpL7xtJDiv+v1y2cjUPMKve y0HjZSyM sHcnroAjx+kIoRj8hVPw5yvJv7MtBHY2t1/W+RJ1nTrzVdmXUB5Fo9XyYLbIuNRq6f3IvI3wuFwyZQnknrS6mWAEUl+XfkLfTYSiyhbWNCw4Iehg2BDiZoaMwhEAD4AMqoBpJkX1fydYz1Kkcxr6vGQ6cTUyK56krt+bHI3Cqghp2wtfd1p7CH7xxKR0VmTOjT5aU7tEkTKV7Dhoiseb46sW7mzN/+UWkhp/SpRGy/7zTJMmj2FM8Lctq0IIe/2c8Q+PYtzZbgM52zSrgxpDypmtxk4hjTUCmCvySk62qsVNF8W+hFblCq0ap2DkqH3oqrQppw5Yy0rjocyOSSYBlj0IeBQ== 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: On 1/22/26 18:02, Kevin Brodsky wrote: > FORCE_READ(*addr) ensures that the compiler will emit a load from > addr. Several tests need to trigger such a load for a range of > pages, ensuring that every page is faulted in, if it wasn't already. > > Introduce a new helper force_read_pages() that does exactly that and > replace existing loops with a call to it. > > The step size (regular/huge page size) is preserved for all loops, > except in split_huge_page_test. Reading every byte is unnecessary; > we now read every huge page, matching the following call to > check_huge_file(). > > Reviewed-by: Dev Jain > Signed-off-by: Kevin Brodsky > --- > tools/testing/selftests/mm/hugetlb-madvise.c | 9 +-------- > tools/testing/selftests/mm/pfnmap.c | 9 +++------ > tools/testing/selftests/mm/split_huge_page_test.c | 6 +----- > tools/testing/selftests/mm/vm_util.h | 7 +++++++ > 4 files changed, 12 insertions(+), 19 deletions(-) > > diff --git a/tools/testing/selftests/mm/hugetlb-madvise.c b/tools/testing/selftests/mm/hugetlb-madvise.c > index 05d9d2805ae4..5b12041fa310 100644 > --- a/tools/testing/selftests/mm/hugetlb-madvise.c > +++ b/tools/testing/selftests/mm/hugetlb-madvise.c > @@ -47,14 +47,7 @@ void write_fault_pages(void *addr, unsigned long nr_pages) > > void read_fault_pages(void *addr, unsigned long nr_pages) > { > - unsigned long i; > - > - for (i = 0; i < nr_pages; i++) { > - unsigned long *addr2 = > - ((unsigned long *)(addr + (i * huge_page_size))); > - /* Prevent the compiler from optimizing out the entire loop: */ > - FORCE_READ(*addr2); > - } > + force_read_pages(addr, nr_pages, huge_page_size); > } Likely we could get rid of read_fault_pages() completely and simply let the callers call force_read_pages() now? Acked-by: David Hildenbrand (Red Hat) -- Cheers David