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| author | Mao Bibo <maobibo@loongson.cn> | 2022-05-10 13:44:41 +0200 |
|---|---|---|
| committer | Thomas Bogendoerfer <tsbogend@alpha.franken.de> | 2022-05-12 17:56:21 +0200 |
| commit | 84595f450a8fc773a5543e2a0cca55067db38a8d (patch) | |
| tree | b87941411c172d60060ad0a7f153955f639d5233 /arch/mips/kernel | |
| parent | MIPS: adding a safety check for cpu_has_fpu (diff) | |
| download | linux-84595f450a8fc773a5543e2a0cca55067db38a8d.tar.xz linux-84595f450a8fc773a5543e2a0cca55067db38a8d.zip | |
MIPS: smp: optimization for flush_tlb_mm when exiting
When process exits or execute new binary, it will call function
exit_mmap with old mm, there is such function call trace:
exit_mmap(struct mm_struct *mm)
--> tlb_finish_mmu(&tlb, 0, -1)
--> arch_tlb_finish_mmu(tlb, start, end, force)
--> tlb_flush_mmu(tlb);
--> tlb_flush(struct mmu_gather *tlb)
--> flush_tlb_mm(tlb->mm)
It is not necessary to flush tlb since oldmm is not used anymore
by the process, there is similar operations on IA64/ARM64 etc,
this patch adds such optimization on MIPS.
Signed-off-by: Mao Bibo <maobibo@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Diffstat (limited to 'arch/mips/kernel')
| -rw-r--r-- | arch/mips/kernel/smp.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c index 1986d1309410..1d93b85271ba 100644 --- a/arch/mips/kernel/smp.c +++ b/arch/mips/kernel/smp.c @@ -518,6 +518,12 @@ static inline void smp_on_each_tlb(void (*func) (void *info), void *info) void flush_tlb_mm(struct mm_struct *mm) { + if (!mm) + return; + + if (atomic_read(&mm->mm_users) == 0) + return; /* happens as a result of exit_mmap() */ + preempt_disable(); if (cpu_has_mmid) { |