From: "tip-bot2 for Nadav Amit" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Nadav Amit <namit@vmware.com>, Ingo Molnar <mingo@kernel.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: x86/mm] x86/mm/tlb: Do not make is_lazy dirty for no reason
Date: Sat, 06 Mar 2021 12:12:54 -0000 [thread overview]
Message-ID: <161503277478.398.10679282978114075916.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210220231712.2475218-7-namit@vmware.com>
The following commit has been merged into the x86/mm branch of tip:
Commit-ID: 09c5272e48614a30598e759c3c7bed126d22037d
Gitweb: https://git.kernel.org/tip/09c5272e48614a30598e759c3c7bed126d22037d
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Sat, 20 Feb 2021 15:17:09 -08:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Sat, 06 Mar 2021 12:59:10 +01:00
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: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20210220231712.2475218-7-namit@vmware.com
---
arch/x86/mm/tlb.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 345a0af..17ec4bf 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -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
next prev parent reply other threads:[~2021-03-06 12:14 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-20 23:17 [PATCH v6 0/9] x86/tlb: Concurrent TLB flushes Nadav Amit
2021-02-20 23:17 ` [PATCH v6 1/9] smp: Run functions concurrently in smp_call_function_many_cond() Nadav Amit
2021-03-01 17:10 ` Peter Zijlstra
2021-03-01 19:01 ` Nadav Amit
2021-03-02 7:05 ` [PATCH] smp: Micro-optimize smp_call_function_many_cond() Ingo Molnar
2021-03-02 9:54 ` [tip: x86/mm] smp: Run functions concurrently in smp_call_function_many_cond() tip-bot2 for Nadav Amit
2021-03-06 12:12 ` tip-bot2 for Nadav Amit
2021-02-20 23:17 ` [PATCH v6 2/9] x86/mm/tlb: Unify flush_tlb_func_local() and flush_tlb_func_remote() Nadav Amit
2021-03-02 9:54 ` [tip: x86/mm] " tip-bot2 for Nadav Amit
2021-03-06 12:12 ` tip-bot2 for Nadav Amit
2021-02-20 23:17 ` [PATCH v6 3/9] x86/mm/tlb: Open-code on_each_cpu_cond_mask() for tlb_is_not_lazy() Nadav Amit
2021-03-02 9:54 ` [tip: x86/mm] " tip-bot2 for Nadav Amit
2021-03-06 12:12 ` tip-bot2 for Nadav Amit
2021-02-20 23:17 ` [PATCH v6 4/9] x86/mm/tlb: Flush remote and local TLBs concurrently Nadav Amit
2021-03-02 9:54 ` [tip: x86/mm] " tip-bot2 for Nadav Amit
2021-03-06 12:12 ` tip-bot2 for Nadav Amit
2021-02-20 23:17 ` [PATCH v6 5/9] x86/mm/tlb: Privatize cpu_tlbstate Nadav Amit
2021-03-02 9:54 ` [tip: x86/mm] " tip-bot2 for Nadav Amit
2021-03-06 12:12 ` tip-bot2 for Nadav Amit
2021-02-20 23:17 ` [PATCH v6 6/9] x86/mm/tlb: Do not make is_lazy dirty for no reason Nadav Amit
2021-03-02 9:54 ` [tip: x86/mm] " tip-bot2 for Nadav Amit
2021-03-06 12:12 ` tip-bot2 for Nadav Amit [this message]
2021-02-20 23:17 ` [PATCH v6 7/9] cpumask: Mark functions as pure Nadav Amit
2021-03-02 9:54 ` [tip: x86/mm] " tip-bot2 for Nadav Amit
2021-03-06 12:12 ` tip-bot2 for Nadav Amit
2021-02-20 23:17 ` [PATCH v6 8/9] x86/mm/tlb: Remove unnecessary uses of the inline keyword Nadav Amit
2021-03-02 9:54 ` [tip: x86/mm] " tip-bot2 for Nadav Amit
2021-03-06 12:12 ` tip-bot2 for Nadav Amit
2021-02-20 23:17 ` [PATCH v6 9/9] smp: inline on_each_cpu_cond() and on_each_cpu() Nadav Amit
2021-03-02 9:54 ` [tip: x86/mm] smp: Inline " tip-bot2 for Nadav Amit
2021-03-06 12:12 ` tip-bot2 for Nadav Amit
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