提交 09c5272e 编写于 作者: N Nadav Amit 提交者: Ingo Molnar

x86/mm/tlb: Do not make is_lazy dirty for no reason

Blindly writing to is_lazy for no reason, when the written value is
identical to the old value, makes the cacheline dirty for no reason.
Avoid making such writes to prevent cache coherency traffic for no
reason.
Suggested-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NNadav Amit <namit@vmware.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Reviewed-by: NDave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20210220231712.2475218-7-namit@vmware.com
上级 2f4305b1
......@@ -469,7 +469,8 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
__flush_tlb_all();
}
#endif
this_cpu_write(cpu_tlbstate_shared.is_lazy, false);
if (was_lazy)
this_cpu_write(cpu_tlbstate_shared.is_lazy, false);
/*
* The membarrier system call requires a full memory barrier and
......
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