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From: Fenghua Yu <fenghua.yu@intel.com>
To: "Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>, "H Peter Anvin" <hpa@zytor.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Dave Hansen" <dave.hansen@intel.com>,
	"Ashok Raj" <ashok.raj@intel.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Ravi V Shankar" <ravi.v.shankar@intel.com>,
	"Xiaoyao Li " <xiaoyao.li@intel.com>
Cc: "linux-kernel" <linux-kernel@vger.kernel.org>,
	"x86" <x86@kernel.org>,
	kvm@vger.kernel.org, Fenghua Yu <fenghua.yu@intel.com>
Subject: [PATCH v4 02/17] drivers/net/b44: Align pwol_mask to unsigned long for better performance
Date: Fri,  1 Mar 2019 18:44:56 -0800	[thread overview]
Message-ID: <1551494711-213533-3-git-send-email-fenghua.yu@intel.com> (raw)
In-Reply-To: <1551494711-213533-1-git-send-email-fenghua.yu@intel.com>

A bit in pwol_mask is set in b44_magic_pattern automatically by set_bit.
set_bit sets the bit in a single unsigned long location. Since pwol_mask
may not be aligned to unsigned long, the location may cross two cache
lines and accessing the location degradates performance. On x86, accessing
two cache lines in locked instruction in set_bit is called split lock and
can cause overall performance degradation.

To avoid to impact performance by accessing two cache lines in set_bit,
align pwol_mask to unsigned long.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
 drivers/net/ethernet/broadcom/b44.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/b44.c b/drivers/net/ethernet/broadcom/b44.c
index 97ab0dd25552..bc544b6b9c3a 100644
--- a/drivers/net/ethernet/broadcom/b44.c
+++ b/drivers/net/ethernet/broadcom/b44.c
@@ -1547,7 +1547,8 @@ static void b44_setup_pseudo_magicp(struct b44 *bp)
 	u32 val;
 	int plen0, plen1, plen2;
 	u8 *pwol_pattern;
-	u8 pwol_mask[B44_PMASK_SIZE];
+	/* Align to unsigned long for better performance in set_bit() */
+	u8 pwol_mask[B44_PMASK_SIZE] __aligned(sizeof(unsigned long));
 
 	pwol_pattern = kzalloc(B44_PATTERN_SIZE, GFP_KERNEL);
 	if (!pwol_pattern)
-- 
2.7.4


  parent reply	other threads:[~2019-03-02  2:54 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-02  2:44 [PATCH v4 00/17] x86/split_lock: Enable #AC exception for split locked accesses Fenghua Yu
2019-03-02  2:44 ` [PATCH v4 01/17] x86/common: Align cpu_caps_cleared and cpu_caps_set to unsigned long Fenghua Yu
2019-03-04  8:33   ` Paolo Bonzini
2019-03-04 10:17     ` Peter Zijlstra
2019-03-04 10:48       ` Paolo Bonzini
2019-03-04 12:44         ` Peter Zijlstra
2019-03-04 13:13           ` Paolo Bonzini
2019-03-02  2:44 ` Fenghua Yu [this message]
2019-03-04 10:00   ` [PATCH v4 02/17] drivers/net/b44: Align pwol_mask to unsigned long for better performance Peter Zijlstra
2019-03-04 14:45     ` Fenghua Yu
2019-03-04 15:27       ` Peter Zijlstra
2019-03-02  2:44 ` [PATCH v4 03/17] wlcore: Align reg_ch_conf_pending and tmp_ch_bitmap " Fenghua Yu
2019-03-04 10:11   ` Peter Zijlstra
2019-03-04 10:46     ` Paolo Bonzini
2019-03-04 12:41       ` Peter Zijlstra
2019-03-04 13:09         ` Paolo Bonzini
2019-03-04 13:30           ` Peter Zijlstra
2019-03-04 14:40       ` Fenghua Yu
2019-03-04 15:54         ` Paolo Bonzini
2019-03-02  2:44 ` [PATCH v4 04/17] x86/split_lock: Align x86_capability to unsigned long to avoid split locked access Fenghua Yu
2019-03-04 18:52   ` Dave Hansen
2019-03-04 19:15     ` Fenghua Yu
2019-03-04 19:29       ` Dave Hansen
2019-03-04 20:08       ` Peter Zijlstra
2019-03-04 20:12     ` Peter Zijlstra
2019-03-02  2:44 ` [PATCH v4 05/17] x86/cpufeatures: Enumerate IA32_CORE_CAPABILITIES MSR Fenghua Yu
2019-03-04 18:53   ` Dave Hansen
2019-03-04 18:55     ` Yu, Fenghua
2019-03-04 19:01       ` Dave Hansen
2019-03-02  2:45 ` [PATCH v4 06/17] x86/msr-index: Define IA32_CORE_CAPABILITY MSR and #AC exception for split lock bit Fenghua Yu
2019-03-02  2:45 ` [PATCH v4 07/17] x86/split_lock: Enumerate #AC for split lock by MSR IA32_CORE_CAPABILITY Fenghua Yu
2019-03-04 18:58   ` Dave Hansen
2019-03-04 18:59     ` Fenghua Yu
2019-03-04 19:19       ` Dave Hansen
2019-03-02  2:45 ` [PATCH v4 08/17] x86/clearcpuid: Support multiple clearcpuid options Fenghua Yu
2019-03-02  2:45 ` [PATCH v4 09/17] x86/clearcpuid: Support feature flag string in kernel option clearcpuid Fenghua Yu
2019-03-02  2:45 ` [PATCH v4 10/17] x86/clearcpuid: Apply cleared feature bits that are forced set before Fenghua Yu
2019-03-02  2:45 ` [PATCH v4 11/17] x86/clearcpuid: Clear CPUID bit in CPUID faulting Fenghua Yu
2019-03-04 22:04   ` kbuild test robot
2019-03-05  7:27   ` kbuild test robot
2019-03-02  2:45 ` [PATCH v4 12/17] Change document for kernel option clearcpuid Fenghua Yu
2019-03-02  2:45 ` [PATCH v4 13/17] x86/split_lock: Handle #AC exception for split lock Fenghua Yu
2019-03-02  2:45 ` [PATCH v4 14/17] x86/split_lock: Add a sysfs interface to allow user to enable or disable split lock detection on all CPUs during run time Fenghua Yu
2019-03-02  2:45 ` [PATCH v4 15/17] kvm: x86: Report CORE_CAPABILITY on GET_SUPPORTED_CPUID Fenghua Yu
2019-03-04  8:38   ` Paolo Bonzini
2019-03-04 10:47     ` Xiaoyao Li
2019-03-04 10:49       ` Paolo Bonzini
2019-03-04 11:10         ` Xiaoyao Li
2019-03-04 11:14           ` Paolo Bonzini
2019-03-04 11:21             ` Xiaoyao Li
2019-03-05  7:03             ` Xiaoyao Li
2019-03-02  2:45 ` [PATCH v4 16/17] kvm: x86: Add support IA32_CORE_CAPABILITY MSR Fenghua Yu
2019-03-04  8:42   ` Paolo Bonzini
2019-03-04 12:32     ` Xiaoyao Li
2019-03-08  6:10     ` Xiaoyao Li
2019-03-08  7:54       ` Paolo Bonzini
2019-03-08  8:03         ` Xiaoyao Li
2019-03-02  2:45 ` [PATCH v4 17/17] kvm: vmx: Emulate TEST_CTL MSR Fenghua Yu
2019-03-09  2:31   ` Xiaoyao Li
2019-03-11 13:31     ` Paolo Bonzini
2019-03-11 15:10       ` Xiaoyao Li
2019-03-11 15:21         ` Paolo Bonzini
2019-03-11 16:58           ` Xiaoyao Li
2019-03-04 21:55 ` [PATCH v4 00/17] x86/split_lock: Enable #AC exception for split locked accesses Konrad Rzeszutek Wilk
2019-03-05  0:06   ` Fenghua Yu

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