linux-kernel - [PATCH] x86/mm/fault: Put pgd

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1433941708-40686-1-git-send-email-Waiman.Long@hp.com>
Date:	Wed, 10 Jun 2015 09:08:28 -0400
From:	Waiman Long <Waiman.Long@...com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org
Cc:	linux-kernel@...r.kernel.org, Scott J Norton <scott.norton@...com>,
	Douglas Hatch <doug.hatch@...com>,
	Waiman Long <Waiman.Long@...com>
Subject: [PATCH] x86/mm/fault: Put pgd_lock in its own cacheline

On a large system with many cores, massive creation or destruction
of processes/threads can sometime cause a fair amount of spinlock
contention in the pgd_lock used by the pgd_alloc() and pgd_free()
functions. This patch tries to reduce false cacheline sharing by
putting the pgd_lock in its own cacheline which help to reduce
contention on the lock.

Signed-off-by: Waiman Long <Waiman.Long@...com>
---
 arch/x86/mm/fault.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 181c53b..fae48df 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -185,7 +185,7 @@ force_sig_info_fault(int si_signo, int si_code, unsigned long address,
 	force_sig_info(si_signo, &info, tsk);
 }
 
-DEFINE_SPINLOCK(pgd_lock);
+__cacheline_aligned_in_smp DEFINE_SPINLOCK(pgd_lock);
 LIST_HEAD(pgd_list);
 
 #ifdef CONFIG_X86_32
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/