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b=R7OC+bA99ctkDyeRAb0p7Lgp2eukG7MR2xNPuMwyaYvUtoSOole8/rtRG50kNqGgg qwCzQ4prrx3lS75jyF70qfCYRg24/RsNKGyLNAJQehTk8TxxFqVJpXKvnM2DNQn2Pz TsKcQQITzo+ejHHF5etfd7/QVHr7Q9KdzJOyA28sTKll7Xe5suu5sylKc3NEQmOsLl UybVepF43lh5cxDUpcW0E7OzYK9MKD5almH+qNP1ANsXefb9KHU98ExrQUqUrHWKJH dalubLruZlmy9oNt78mDSnLPsbw5t/oocDg2uv9qFalsyscYLElLE75eIGRY1iB7hd KH6GIgM4UrbHg== Message-ID: <69c4c12c-7cdc-4a17-9eb7-6fb1a61f9834@kernel.org> Date: Mon, 27 Apr 2026 11:02:50 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/page_vma_mapped_walk: add missing pgtable entry accessors To: Alexander Gordeev , Andrew Morton , Lorenzo Stoakes Cc: Gerald Schaefer , Heiko Carstens , Vasily Gorbik , linux-s390@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260427052000.196402-1-agordeev@linux.ibm.com> From: "David Hildenbrand (Arm)" 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260427052000.196402-1-agordeev@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 9020040008 X-Stat-Signature: wt8cm8x4zwudwy5moeiexy8p8859ewy6 X-Rspam-User: X-HE-Tag: 1777280577-37437 X-HE-Meta: U2FsdGVkX19PnDmtzf70gCt//FKwhoMo2t/V2TvuD0PM+/AcyLAKH7X8Uj2nrlQPlFxj8VYwbLQakQzGDFarEn5Y3H8mwaAG0EbFEGRZCIOOJDRovgjF4EdvTXyVi4pF7CWkzMMz7cW1EXnXQGBauPJUH69txNcUwNIAEP5NEiKPd7thBz69Fd4ml7JZ319zwbO9c0Pviroussyjqzf5OXyRNA1U4pO9yY+Dpg4NnWhwQEceHaIWggMHUdQbyH5DgnEiOOyWWA9N22I+sCJ5J1gVTjHgcbprJNKazunZbJWWsc+2vlt2SWjrSEhYHL4b3HAJLoWoYupjBEt2HSr1ZMOsrzShv/8wysgIXLHI4clTqULYkKqKO9XhxjoYAMrppM77ut47DRuHZqZsqsbVZnEBjlAbXgjVE6NgC6h1exWyxo4blWf257vpIB1VLaqb//IOhezX6jEqQ1cT/EBmz4uSkvXeyhfOnYx0UyYCnFsG257/7VIh3rVPmF/wYiW37AMll5eoY9aA8w+UmOfnQ1zvH9d9FalL+pqQLoVMYVPeBaD8GW7uKXUDV1C+X5BTosjMHF7d2TjLfDLuEvLCcKK5FnH6vGKc8tsWcUdiD1LyuCsD58G7Zu7oBVh8iPs3ELw2XZ4SvEjM+Gk/72rPUZhPa89ZZOJfcawXe6GBAXoQoKF10KMAgmgienjJD3kXGlpzSNyssDo3xZiURVuMGCWbGC+DCbz1xteB87p0dsufRcmVcyHJ+zzgJUKck8583HKdiFvyWh8FxL/Jvx6LEIKNZATFwkk8IQ2GgEAwz/NHnJDae1M3H5GIEReHFWflqC0s5BsX6B6d5UzaYxhEeD1ahg05eJiXT4xAtLYQU9vfY9K+GuU8Tn6IwI2aNbbBnq3RKi3R14dPDOW6Uo2JfvDHXGbMIrtSkoh0HKVAdhTIf93/gCwcsUuq9LMwQ7gFp/0mAyOlGh+t/wl0/Ia tD2lI/0T gidupVHMnQix/NHMoi/jTzYrTHEvjtA6KzRbVXA91zONOAu5DgvcPfz2AepiVODgjW5ZjTyzuMYgxtE4y1q3YassLXSfpSj5RZvC6kjIE/CZ64pVW631rK+azqxHrx1tWfhKLohcP9qTO4N1Ud64yEXlk3lSUt1b1CIkKLxNA8anjg0ZID36aPg3s7GFg5uct67kiGfSxoqFMvA118zAqxxj/i+cLcLPGkQysY7yZwKvj4oaGdnBe73w2Fa5IQNxbRwmGtKswQ2BUgpxUdxDZneYyfwzdu2/OVXY/a5KVO9AsdpdIzYm+eGy6i2CYQ5VFNBqSLmFq4CL2wQE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/27/26 07:20, Alexander Gordeev wrote: > Convert pgtable direct entry dereferences to the corresponding > pXdp_get() accessors. Use ptep_get_lockless() variant for PTE > reads when no lock is taken. > > Signed-off-by: Alexander Gordeev > --- > mm/page_vma_mapped.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c > index b38a1d00c971..a4520bb10d2a 100644 > --- a/mm/page_vma_mapped.c > +++ b/mm/page_vma_mapped.c > @@ -41,7 +41,7 @@ static bool map_pte(struct page_vma_mapped_walk *pvmw, pmd_t *pmdvalp, > if (!pvmw->pte) > return false; > > - ptent = ptep_get(pvmw->pte); > + ptent = ptep_get_lockless(pvmw->pte); > > if (pte_none(ptent)) { > return false; > @@ -219,17 +219,17 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) > restart: > do { > pgd = pgd_offset(mm, pvmw->address); > - if (!pgd_present(*pgd)) { > + if (!pgd_present(pgdp_get(pgd))) { > step_forward(pvmw, PGDIR_SIZE); > continue; > } > p4d = p4d_offset(pgd, pvmw->address); > - if (!p4d_present(*p4d)) { > + if (!p4d_present(p4dp_get(p4d))) { > step_forward(pvmw, P4D_SIZE); > continue; > } > pud = pud_offset(p4d, pvmw->address); > - if (!pud_present(*pud)) { > + if (!pud_present(pudp_get(pud))) { > step_forward(pvmw, PUD_SIZE); > continue; Wasn't there a problem with folded page tables, where we would no longer be able to optimize out the folded page table accesses? I thought we discussed ways to resolve that. Let me dig ... -- Cheers, David