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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 6DC52100008 X-Stat-Signature: 5hfstp1ooq9hbsrmhimke7rsnnxxuyq9 X-Rspam-User: X-HE-Tag: 1739428354-493739 X-HE-Meta: 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 NwJpitKJ V+0J2N8PDs8n6qaJFxbXY8AaPtCvhKN0ruLcRW484ugBYdrR/dlnvIqzNiaPzZ23utnQrIgjzgKl1gEc3JH1T9Md0gZ1yyz8uYFqCksr8G24BxK23mZu28sDk2BiPCRYEq/gQ8ZGvt1Q5+F2+CDJUGYW/eHTO2Pp/M2GimcoUbPXd4HG5PQYxyGBm4T3PVOIWHh+TyW8pp8S765MfMGn2xp2k+eKZBvsuweAuTWwuIIai//qJDi9CM/uY4A== 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 2/7/25 16:50, Ryan Roberts wrote: > On 07/02/2025 10:04, Anshuman Khandual wrote: >> >> >> On 2/5/25 20:39, Ryan Roberts wrote: >>> Implement the required arch functions to enable use of contpte in the >>> vmap when VM_ALLOW_HUGE_VMAP is specified. This speeds up vmap >>> operations due to only having to issue a DSB and ISB per contpte block >>> instead of per pte. But it also means that the TLB pressure reduces due >>> to only needing a single TLB entry for the whole contpte block. >> >> Right. >> >>> >>> Since vmap uses set_huge_pte_at() to set the contpte, that API is now >>> used for kernel mappings for the first time. Although in the vmap case >>> we never expect it to be called to modify a valid mapping so >>> clear_flush() should never be called, it's still wise to make it robust >>> for the kernel case, so amend the tlb flush function if the mm is for >>> kernel space. >> >> Makes sense. >> >>> >>> Tested with vmalloc performance selftests: >>> >>> # kself/mm/test_vmalloc.sh \ >>> run_test_mask=1 >>> test_repeat_count=5 >>> nr_pages=256 >>> test_loop_count=100000 >>> use_huge=1 >>> >>> Duration reduced from 1274243 usec to 1083553 usec on Apple M2 for 15% >>> reduction in time taken. >>> >>> Signed-off-by: Ryan Roberts >>> --- >>> arch/arm64/include/asm/vmalloc.h | 40 ++++++++++++++++++++++++++++++++ >>> arch/arm64/mm/hugetlbpage.c | 5 +++- >>> 2 files changed, 44 insertions(+), 1 deletion(-) >>> >>> diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h >>> index 38fafffe699f..fbdeb40f3857 100644 >>> --- a/arch/arm64/include/asm/vmalloc.h >>> +++ b/arch/arm64/include/asm/vmalloc.h >>> @@ -23,6 +23,46 @@ static inline bool arch_vmap_pmd_supported(pgprot_t prot) >>> return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS); >>> } >>> >>> +#define arch_vmap_pte_range_map_size arch_vmap_pte_range_map_size >>> +static inline unsigned long arch_vmap_pte_range_map_size(unsigned long addr, >>> + unsigned long end, u64 pfn, >>> + unsigned int max_page_shift) >>> +{ >>> + if (max_page_shift < CONT_PTE_SHIFT) >>> + return PAGE_SIZE; >>> + >>> + if (end - addr < CONT_PTE_SIZE) >>> + return PAGE_SIZE; >>> + >>> + if (!IS_ALIGNED(addr, CONT_PTE_SIZE)) >>> + return PAGE_SIZE; >>> + >>> + if (!IS_ALIGNED(PFN_PHYS(pfn), CONT_PTE_SIZE)) >>> + return PAGE_SIZE; >>> + >>> + return CONT_PTE_SIZE; >> >> A small nit: >> >> Should the rationale behind picking CONT_PTE_SIZE be added here as an in code >> comment or something in the function - just to make things bit clear. > > I'm not sure what other size we would pick? The suggestion was to add a small comment in the above helper function explaining the rationale for various conditions in there while returning either PAGE_SIZE or CONT_PTE_SIZE to improve readability etc. > >> >>> +} >>> + >>> +#define arch_vmap_pte_range_unmap_size arch_vmap_pte_range_unmap_size >>> +static inline unsigned long arch_vmap_pte_range_unmap_size(unsigned long addr, >>> + pte_t *ptep) >>> +{ >>> + /* >>> + * The caller handles alignment so it's sufficient just to check >>> + * PTE_CONT. >>> + */ >>> + return pte_valid_cont(__ptep_get(ptep)) ? CONT_PTE_SIZE : PAGE_SIZE; >> >> I guess it is safe to query the CONT_PTE from the mapped entry itself. > > Yes I don't see why not. Is there some specific aspect you're concerned about? Nothing came up while following this code, it was more of a general observation. > >> >>> +} >>> + >>> +#define arch_vmap_pte_supported_shift arch_vmap_pte_supported_shift >>> +static inline int arch_vmap_pte_supported_shift(unsigned long size) >>> +{ >>> + if (size >= CONT_PTE_SIZE) >>> + return CONT_PTE_SHIFT; >>> + >>> + return PAGE_SHIFT; >>> +} >>> + >>> #endif >>> >>> #define arch_vmap_pgprot_tagged arch_vmap_pgprot_tagged >>> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c >>> index 02afee31444e..a74e43101dad 100644 >>> --- a/arch/arm64/mm/hugetlbpage.c >>> +++ b/arch/arm64/mm/hugetlbpage.c >>> @@ -217,7 +217,10 @@ static void clear_flush(struct mm_struct *mm, >>> for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) >>> ___ptep_get_and_clear(mm, ptep, pgsize); >>> >>> - __flush_hugetlb_tlb_range(&vma, saddr, addr, pgsize, true); >>> + if (mm == &init_mm) >>> + flush_tlb_kernel_range(saddr, addr); >>> + else >>> + __flush_hugetlb_tlb_range(&vma, saddr, addr, pgsize, true); >>> } >>> >>> void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, >> >> Otherwise LGTM. >> >> Reviewed-by: Anshuman Khandual > > Thanks! > >