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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 3C97B40006 X-Stat-Signature: dt3eorsm7y45exudfeqz8k9nbrdosg1b X-HE-Tag: 1745909692-732587 X-HE-Meta: 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 GFG7SApP cEfT98zOyuNyDXtyuLbZJqOEB5Q14l9CoSm4A4nbB7gKLP9yjr5WxfivUQGJz9wz5hGWuZbgoap7ZQHCPePAZRsm2bU8IRUSGLAYxwDXMTY3ceCaASbEZfZ03qkAJ5/tGGvSeZm5StEjd0hZUTRarQhPegJ6L45yzmrPN8T0SpM7RbrlQCmUyDXYd3k/ROdPucVVdQszxREa9Tck= 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 29/04/25 12:11 pm, Anshuman Khandual wrote: > > > On 4/29/25 10:53, Dev Jain wrote: >> Reduce indentation in change_pte_range() by refactoring some of the code >> into a new function. No functional change. >> >> Signed-off-by: Dev Jain >> --- >> mm/mprotect.c | 116 +++++++++++++++++++++++++++++--------------------- >> 1 file changed, 68 insertions(+), 48 deletions(-) >> >> diff --git a/mm/mprotect.c b/mm/mprotect.c >> index 88608d0dc2c2..70f59aa8c2a8 100644 >> --- a/mm/mprotect.c >> +++ b/mm/mprotect.c >> @@ -83,6 +83,71 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, >> return pte_dirty(pte); >> } >> >> + >> + >> +static bool prot_numa_skip(struct vm_area_struct *vma, struct folio *folio, >> + int target_node) >> +{ >> + bool toptier; >> + int nid; >> + >> + /* Also skip shared copy-on-write pages */ >> + if (is_cow_mapping(vma->vm_flags) && >> + (folio_maybe_dma_pinned(folio) || >> + folio_maybe_mapped_shared(folio))) >> + return true; >> + >> + /* >> + * While migration can move some dirty pages, >> + * it cannot move them all from MIGRATE_ASYNC >> + * context. >> + */ >> + if (folio_is_file_lru(folio) && >> + folio_test_dirty(folio)) >> + return true; >> + >> + /* >> + * Don't mess with PTEs if page is already on the node >> + * a single-threaded process is running on. >> + */ >> + nid = folio_nid(folio); >> + if (target_node == nid) >> + return true; >> + toptier = node_is_toptier(nid); >> + >> + /* >> + * Skip scanning top tier node if normal numa >> + * balancing is disabled >> + */ >> + if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && >> + toptier) >> + return true; >> + return false; >> +} >> + >> +static bool prot_numa_avoid_fault(struct vm_area_struct *vma, >> + unsigned long addr, pte_t oldpte, int target_node) >> +{ >> + struct folio *folio; >> + int ret; >> + >> + /* Avoid TLB flush if possible */ >> + if (pte_protnone(oldpte)) >> + return true; >> + >> + folio = vm_normal_folio(vma, addr, oldpte); >> + if (!folio || folio_is_zone_device(folio) || >> + folio_test_ksm(folio)) >> + return true; >> + ret = prot_numa_skip(vma, folio, target_node); > > What purpose does it solve to create additional helper prot_numa_skip(). > IOW - why cannot all of these be inside prot_numa_avoid_fault() itself. That is in preparation for patch 2, so that I can skip a PTE batch. > >> + if (ret) >> + return ret; >> + if (folio_use_access_time(folio)) >> + folio_xchg_access_time(folio, >> + jiffies_to_msecs(jiffies)); >> + return false; >> +} >> + >> static long change_pte_range(struct mmu_gather *tlb, >> struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, >> unsigned long end, pgprot_t newprot, unsigned long cp_flags) >> @@ -116,56 +181,11 @@ static long change_pte_range(struct mmu_gather *tlb, >> * Avoid trapping faults against the zero or KSM >> * pages. See similar comment in change_huge_pmd. >> */ >> - if (prot_numa) { >> - struct folio *folio; >> - int nid; >> - bool toptier; >> - >> - /* Avoid TLB flush if possible */ >> - if (pte_protnone(oldpte)) >> - continue; >> - >> - folio = vm_normal_folio(vma, addr, oldpte); >> - if (!folio || folio_is_zone_device(folio) || >> - folio_test_ksm(folio)) >> - continue; >> - >> - /* Also skip shared copy-on-write pages */ >> - if (is_cow_mapping(vma->vm_flags) && >> - (folio_maybe_dma_pinned(folio) || >> - folio_maybe_mapped_shared(folio))) >> - continue; >> - >> - /* >> - * While migration can move some dirty pages, >> - * it cannot move them all from MIGRATE_ASYNC >> - * context. >> - */ >> - if (folio_is_file_lru(folio) && >> - folio_test_dirty(folio)) >> + if (prot_numa && >> + prot_numa_avoid_fault(vma, addr, >> + oldpte, target_node)) >> continue; >> >> - /* >> - * Don't mess with PTEs if page is already on the node >> - * a single-threaded process is running on. >> - */ >> - nid = folio_nid(folio); >> - if (target_node == nid) >> - continue; >> - toptier = node_is_toptier(nid); >> - >> - /* >> - * Skip scanning top tier node if normal numa >> - * balancing is disabled >> - */ >> - if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && >> - toptier) >> - continue; >> - if (folio_use_access_time(folio)) >> - folio_xchg_access_time(folio, >> - jiffies_to_msecs(jiffies)); >> - } >> - >> oldpte = ptep_modify_prot_start(vma, addr, pte); >> ptent = pte_modify(oldpte, newprot); >>