Re: [RFC PATCH v5 4/8] mm: tlb: Pass struct mmu_gather to flush_pmd_tlb_range
From: Peter Zijlstra <peterz@infradead.org>
Date: 2020-03-31 15:14:28
Also in:
linux-arch, linux-mm, lkml
On Tue, Mar 31, 2020 at 10:29:23PM +0800, Zhenyu Ye wrote:
quoted hunk ↗ jump to hunk
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index e2e2bef07dd2..32d4661e5a56 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h@@ -1160,10 +1160,10 @@ static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) * invalidate the entire TLB which is not desitable. * e.g. see arch/arc: flush_pmd_tlb_range */ -#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) +#define flush_pmd_tlb_range(tlb, vma, addr, end) flush_tlb_range(vma, addr, end) #define flush_pud_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) #else -#define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG() +#define flush_pmd_tlb_range(tlb, vma, addr, end) BUILD_BUG() #define flush_pud_tlb_range(vma, addr, end) BUILD_BUG() #endif #endifdiff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c index 3d7c01e76efc..96c9cf77bfb5 100644 --- a/mm/pgtable-generic.c +++ b/mm/pgtable-generic.c@@ -109,8 +109,14 @@ int pmdp_set_access_flags(struct vm_area_struct *vma, int changed = !pmd_same(*pmdp, entry); VM_BUG_ON(address & ~HPAGE_PMD_MASK); if (changed) { + struct mmu_gather tlb; + unsigned long tlb_start = address; + unsigned long tlb_end = address + HPAGE_PMD_SIZE; set_pmd_at(vma->vm_mm, address, pmdp, entry); - flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); + tlb_gather_mmu(&tlb, vma->vm_mm, tlb_start, tlb_end); + tlb.cleared_pmds = 1; + flush_pmd_tlb_range(&tlb, vma, tlb_start, tlb_end); + tlb_finish_mmu(&tlb, tlb_start, tlb_end); } return changed; }
This is madness. Please, carefully consider what you just wrote and what it will do in the generic case. Instead of trying to retro-fit flush_*tlb_range() to take an mmu_gather parameter, please replace them out-right. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel