From: Bibo Mao <maobibo@xxxxxxxxxxx> Subject: MIPS: do not call flush_tlb_all when setting pmd entry Function set_pmd_at is to set pmd entry, if tlb entry need to be flushed, there exists pmdp_huge_clear_flush alike function before set_pmd_at is called. So it is not necessary to call flush_tlb_all in this function. In these scenarios, tlb for the pmd range needs to be flushed: 1. privilege degrade such as wrprotect is set on the pmd entry 2. pmd entry is cleared 3. there is exception if set_pmd_at is issued by dup_mmap, since flush_tlb_mm is called for parent process, it is not necessary to flush tlb in function copy_huge_pmd. Link: http://lkml.kernel.org/r/1592990792-1923-3-git-send-email-maobibo@xxxxxxxxxxx Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx> Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx> Cc: Daniel Silsby <dansilsby@xxxxxxxxx> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: Paul Burton <paulburton@xxxxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/mips/mm/pgtable-32.c | 1 - arch/mips/mm/pgtable-64.c | 1 - 2 files changed, 2 deletions(-) --- a/arch/mips/mm/pgtable-32.c~mips-do-not-call-flush_tlb_all-when-setting-pmd-entry +++ a/arch/mips/mm/pgtable-32.c @@ -45,7 +45,6 @@ void set_pmd_at(struct mm_struct *mm, un pmd_t *pmdp, pmd_t pmd) { *pmdp = pmd; - flush_tlb_all(); } #endif /* defined(CONFIG_TRANSPARENT_HUGEPAGE) */ --- a/arch/mips/mm/pgtable-64.c~mips-do-not-call-flush_tlb_all-when-setting-pmd-entry +++ a/arch/mips/mm/pgtable-64.c @@ -100,7 +100,6 @@ void set_pmd_at(struct mm_struct *mm, un pmd_t *pmdp, pmd_t pmd) { *pmdp = pmd; - flush_tlb_all(); } void __init pagetable_init(void) _
