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Tsirkin" , linux-kernel@vger.kernel.org Cc: Andrew Morton , Vlastimil Babka , Brendan Jackman , Michal Hocko , Suren Baghdasaryan , Jason Wang , Andrea Arcangeli , linux-mm@kvack.org, virtualization@lists.linux.dev, Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport References: <39c3c8e647fc4c8e3dcb5c9d12f2e29b5404e8f2.1776689093.git.mst@redhat.com> <068cdadf-d979-4170-9ff3-2468f46e9786@kernel.org> 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: <068cdadf-d979-4170-9ff3-2468f46e9786@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: BCA10C0006 X-Stat-Signature: daqrqwej5wendfnnn6t1xjwqfp1kurzz X-Rspam-User: X-HE-Tag: 1776770737-849787 X-HE-Meta: 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 zThImKWZ +136Je8TjIdZIgp4JGZFoq4EhwoizIg+8DH37TGb6ne3j8k84ivBC6SKf6uv5fHw0XDR1Fm/I5NFMJES3Ws0u7efyMPfbgwOKY9c0HAT61h6LyJTZKOSN1K9jMuxBEAzktwb+Kf5H1vaw6obJWfLcyoWnJwyQ3AouJDQPj2vy/WHX2H9YVfig8v5yD1BKcWdORU1Lu5HQUTDDDh5OJ9w/cWWJmrkC8G4zJGQ2yRgH1zswd9Vzcf1wbyCs+pntKFUVJLohbaRNZMXSNzmAUwomr/X+PHajTZndCslLmAS2DDMxZPf6T0nCQH08m2fwUL5Wo8Niztg1Mv1vtHQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/21/26 13:12, David Hildenbrand (Arm) wrote: > On 4/21/26 12:58, David Hildenbrand (Arm) wrote: >> On 4/20/26 14:50, Michael S. Tsirkin wrote: >>> Use vma_alloc_folio_hints() and check PGHINT_ZEROED to skip >>> clear_user_highpage() when the page is already zeroed. >>> >>> On x86, vma_alloc_zeroed_movable_folio is overridden by a macro >>> that uses __GFP_ZERO directly, so this change has no effect there. >>> >>> Signed-off-by: Michael S. Tsirkin >>> Assisted-by: Claude:claude-opus-4-6 >>> Assisted-by: cursor-agent:GPT-5.4-xhigh >>> --- >>> include/linux/highmem.h | 6 ++++-- >>> 1 file changed, 4 insertions(+), 2 deletions(-) >>> >>> diff --git a/include/linux/highmem.h b/include/linux/highmem.h >>> index af03db851a1d..8bb67772c1cb 100644 >>> --- a/include/linux/highmem.h >>> +++ b/include/linux/highmem.h >>> @@ -321,9 +321,11 @@ struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma, >>> unsigned long vaddr) >>> { >>> struct folio *folio; >>> + pghint_t hints; >>> >>> - folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, vaddr); >>> - if (folio && user_alloc_needs_zeroing()) >>> + folio = vma_alloc_folio_hints(GFP_HIGHUSER_MOVABLE, 0, vma, vaddr, >>> + &hints); >>> + if (folio && user_alloc_needs_zeroing() && !(hints & PGHINT_ZEROED)) >>> clear_user_highpage(&folio->page, vaddr); >>> >>> return folio; >> >> >> For others reading along, the variant on your other branch: >> >> diff --git a/include/linux/highmem.h b/include/linux/highmem.h >> index af03db851a1d9..ffa683f64f1d1 100644 >> --- a/include/linux/highmem.h >> +++ b/include/linux/highmem.h >> @@ -320,13 +320,8 @@ static inline >> struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma, >> unsigned long vaddr) >> { >> - struct folio *folio; >> - >> - folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, vaddr); >> - if (folio && user_alloc_needs_zeroing()) >> - clear_user_highpage(&folio->page, vaddr); >> - >> - return folio; >> + return vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, >> + 0, vma, vaddr); >> } >> #endif >> >> Looks like an extremely clean interface. >> > > And we could likely just do the following on top I assume. > > diff --git a/arch/m68k/include/asm/page_no.h b/arch/m68k/include/asm/page_no.h > index d2532bc407ef..f511b763a235 100644 > --- a/arch/m68k/include/asm/page_no.h > +++ b/arch/m68k/include/asm/page_no.h > @@ -12,9 +12,6 @@ extern unsigned long memory_end; > > #define copy_user_page(to, from, vaddr, pg) copy_page(to, from) > > -#define vma_alloc_zeroed_movable_folio(vma, vaddr) \ > - vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr) > - > #define __pa(vaddr) ((unsigned long)(vaddr)) > #define __va(paddr) ((void *)((unsigned long)(paddr))) > > diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h > index 56da819a79e6..e995d2a413f9 100644 > --- a/arch/s390/include/asm/page.h > +++ b/arch/s390/include/asm/page.h > @@ -67,9 +67,6 @@ static inline void copy_page(void *to, void *from) > > #define copy_user_page(to, from, vaddr, pg) copy_page(to, from) > > -#define vma_alloc_zeroed_movable_folio(vma, vaddr) \ > - vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr) > - > #ifdef CONFIG_STRICT_MM_TYPECHECKS > #define STRICT_MM_TYPECHECKS > #endif > diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h > index 416dc88e35c1..92fa975b46f3 100644 > --- a/arch/x86/include/asm/page.h > +++ b/arch/x86/include/asm/page.h > @@ -28,9 +28,6 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr, > copy_page(to, from); > } > > -#define vma_alloc_zeroed_movable_folio(vma, vaddr) \ > - vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr) > - > #ifndef __pa > #define __pa(x) __phys_addr((unsigned long)(x)) > #endif > > ... and I wonder whether we could then convert the arm64 variant into a simple helper that just returns additional gfp flags. We might even be able to call that from inside vma_alloc_folio(), to just get __GFP_ZEROTAGS whenever the VMA has VM_MTE. But that's obviously some additional work on top. -- Cheers, David