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From: Peter Zijlstra <peterz@infradead.org>
To: Nadav Amit <nadav.amit@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Nadav Amit <namit@vmware.com>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Sasha Levin <sashal@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, Juergen Gross <jgross@suse.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	linux-hyperv@vger.kernel.org,
	virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
	xen-devel@lists.xenproject.org,
	Michael Kelley <mikelley@microsoft.com>
Subject: Re: [PATCH v5 4/8] x86/mm/tlb: Flush remote and local TLBs concurrently
Date: Tue, 16 Feb 2021 13:10:25 +0100	[thread overview]
Message-ID: <YCu2MQFdV4JTrUQb@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210209221653.614098-5-namit@vmware.com>

On Tue, Feb 09, 2021 at 02:16:49PM -0800, Nadav Amit wrote:
> @@ -816,8 +821,8 @@ STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask,
>  	 * doing a speculative memory access.
>  	 */
>  	if (info->freed_tables) {
> -		smp_call_function_many(cpumask, flush_tlb_func,
> -			       (void *)info, 1);
> +		on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
> +				      cpumask);
>  	} else {
>  		/*
>  		 * Although we could have used on_each_cpu_cond_mask(),
> @@ -844,14 +849,15 @@ STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask,
>  			if (tlb_is_not_lazy(cpu))
>  				__cpumask_set_cpu(cpu, cond_cpumask);
>  		}
> -		smp_call_function_many(cond_cpumask, flush_tlb_func, (void *)info, 1);
> +		on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
> +				      cpumask);
>  	}
>  }

Surely on_each_cpu_mask() is more appropriate? There the compiler can do
the NULL propagation because it's on the same TU.

--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -821,8 +821,7 @@ STATIC_NOPV void native_flush_tlb_multi(
 	 * doing a speculative memory access.
 	 */
 	if (info->freed_tables) {
-		on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
-				      cpumask);
+		on_each_cpu_mask(cpumask, flush_tlb_func, (void *)info, true);
 	} else {
 		/*
 		 * Although we could have used on_each_cpu_cond_mask(),
@@ -849,8 +848,7 @@ STATIC_NOPV void native_flush_tlb_multi(
 			if (tlb_is_not_lazy(cpu))
 				__cpumask_set_cpu(cpu, cond_cpumask);
 		}
-		on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
-				      cpumask);
+		on_each_cpu_mask(cpumask, flush_tlb_func, (void *)info, true);
 	}
 }
 

WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Nadav Amit <nadav.amit@gmail.com>
Cc: Sasha Levin <sashal@kernel.org>, Juergen Gross <jgross@suse.com>,
	linux-hyperv@vger.kernel.org, x86@kernel.org,
	Stephen Hemminger <sthemmin@microsoft.com>,
	xen-devel@lists.xenproject.org, kvm@vger.kernel.org,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	Ingo Molnar <mingo@redhat.com>, Nadav Amit <namit@vmware.com>,
	Andy Lutomirski <luto@kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Michael Kelley <mikelley@microsoft.com>
Subject: Re: [PATCH v5 4/8] x86/mm/tlb: Flush remote and local TLBs concurrently
Date: Tue, 16 Feb 2021 13:10:25 +0100	[thread overview]
Message-ID: <YCu2MQFdV4JTrUQb@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210209221653.614098-5-namit@vmware.com>

On Tue, Feb 09, 2021 at 02:16:49PM -0800, Nadav Amit wrote:
> @@ -816,8 +821,8 @@ STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask,
>  	 * doing a speculative memory access.
>  	 */
>  	if (info->freed_tables) {
> -		smp_call_function_many(cpumask, flush_tlb_func,
> -			       (void *)info, 1);
> +		on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
> +				      cpumask);
>  	} else {
>  		/*
>  		 * Although we could have used on_each_cpu_cond_mask(),
> @@ -844,14 +849,15 @@ STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask,
>  			if (tlb_is_not_lazy(cpu))
>  				__cpumask_set_cpu(cpu, cond_cpumask);
>  		}
> -		smp_call_function_many(cond_cpumask, flush_tlb_func, (void *)info, 1);
> +		on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
> +				      cpumask);
>  	}
>  }

Surely on_each_cpu_mask() is more appropriate? There the compiler can do
the NULL propagation because it's on the same TU.

--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -821,8 +821,7 @@ STATIC_NOPV void native_flush_tlb_multi(
 	 * doing a speculative memory access.
 	 */
 	if (info->freed_tables) {
-		on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
-				      cpumask);
+		on_each_cpu_mask(cpumask, flush_tlb_func, (void *)info, true);
 	} else {
 		/*
 		 * Although we could have used on_each_cpu_cond_mask(),
@@ -849,8 +848,7 @@ STATIC_NOPV void native_flush_tlb_multi(
 			if (tlb_is_not_lazy(cpu))
 				__cpumask_set_cpu(cpu, cond_cpumask);
 		}
-		on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
-				      cpumask);
+		on_each_cpu_mask(cpumask, flush_tlb_func, (void *)info, true);
 	}
 }
 
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Virtualization@lists.linux-foundation.org
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  reply	other threads:[~2021-02-16 12:12 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-09 22:16 [PATCH v5 0/8] x86/tlb: Concurrent TLB flushes Nadav Amit
2021-02-09 22:16 ` Nadav Amit
2021-02-09 22:16 ` [PATCH v5 1/8] smp: Run functions concurrently in smp_call_function_many_cond() Nadav Amit
2021-02-16 12:04   ` Peter Zijlstra
2021-02-16 18:49     ` Nadav Amit
2021-02-16 12:06   ` Peter Zijlstra
2021-02-16 16:32   ` Peter Zijlstra
2021-02-16 18:53     ` Nadav Amit
2021-02-16 18:59       ` Peter Zijlstra
2021-02-16 19:04         ` Nadav Amit
2021-02-17  1:02         ` Nadav Amit
2021-02-18 12:55           ` Peter Zijlstra
2021-02-18  8:09   ` Christoph Hellwig
2021-02-18  9:36     ` Nadav Amit
2021-02-18 11:12       ` Peter Zijlstra
2021-02-09 22:16 ` [PATCH v5 2/8] x86/mm/tlb: Unify flush_tlb_func_local() and flush_tlb_func_remote() Nadav Amit
2021-02-09 22:16 ` [PATCH v5 3/8] x86/mm/tlb: Open-code on_each_cpu_cond_mask() for tlb_is_not_lazy() Nadav Amit
2021-02-18  8:16   ` Christoph Hellwig
2021-02-18  8:24     ` Nadav Amit
2021-02-18  8:28       ` Christoph Hellwig
2021-02-09 22:16 ` [PATCH v5 4/8] x86/mm/tlb: Flush remote and local TLBs concurrently Nadav Amit
2021-02-09 22:16   ` Nadav Amit
2021-02-16 12:10   ` Peter Zijlstra [this message]
2021-02-16 12:10     ` Peter Zijlstra
2021-02-16 19:17     ` Nadav Amit
2021-02-16 19:17       ` Nadav Amit
2021-02-18  8:14   ` Christoph Hellwig
2021-02-18  8:14     ` Christoph Hellwig
2021-02-09 22:16 ` [PATCH v5 5/8] x86/mm/tlb: Privatize cpu_tlbstate Nadav Amit
2021-02-09 22:16 ` [PATCH v5 6/8] x86/mm/tlb: Do not make is_lazy dirty for no reason Nadav Amit
2021-02-09 22:16 ` [PATCH v5 7/8] cpumask: Mark functions as pure Nadav Amit
2021-02-16 12:14   ` Peter Zijlstra
2021-02-09 22:16 ` [PATCH v5 8/8] x86/mm/tlb: Remove unnecessary uses of the inline keyword Nadav Amit

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