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From: Ravikiran G Thirumalai <kiran@scalex86.org>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org,
	"Shai Fultheim (Shai@scalex86.org)" <shai@scalex86.org>
Subject: [patch] Cache align futex hash buckets
Date: Mon, 20 Feb 2006 15:32:42 -0800	[thread overview]
Message-ID: <20060220233242.GC3594@localhost.localdomain> (raw)

Following change places each element of the futex_queues hashtable on a 
different cacheline.  Spinlocks of adjacent hash buckets lie on the same 
cacheline otherwise.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>

Index: linux-2.6.16-rc2/kernel/futex.c
===================================================================
--- linux-2.6.16-rc2.orig/kernel/futex.c	2006-02-07 23:14:04.000000000 -0800
+++ linux-2.6.16-rc2/kernel/futex.c	2006-02-09 14:04:22.000000000 -0800
@@ -100,9 +100,10 @@ struct futex_q {
 struct futex_hash_bucket {
        spinlock_t              lock;
        struct list_head       chain;
-};
+} ____cacheline_internodealigned_in_smp;
 
-static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS];
+static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS] 
+				__cacheline_aligned_in_smp;
 
 /* Futex-fs vfsmount entry: */
 static struct vfsmount *futex_mnt;

             reply	other threads:[~2006-02-20 23:32 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-02-20 23:32 Ravikiran G Thirumalai [this message]
2006-02-20 23:33 ` [patch] Cache align futex hash buckets Andrew Morton
2006-02-20 23:34   ` Andrew Morton
2006-02-21  0:09     ` Ravikiran G Thirumalai
2006-02-21  0:23       ` Andrew Morton
2006-02-21  1:04         ` Ravikiran G Thirumalai
2006-02-21  1:09           ` Andrew Morton
2006-02-21  1:39             ` Ravikiran G Thirumalai
2006-02-21 14:44             ` Andi Kleen
2006-02-21  3:30 ` Nick Piggin
2006-02-21 18:33   ` Christoph Lameter
2006-02-21 23:14     ` Christoph Lameter
2006-02-22  0:40     ` Nick Piggin
2006-02-22  2:08       ` Andrew Morton
2006-02-22  2:35         ` Ravikiran G Thirumalai
2006-02-22  2:37         ` Nick Piggin
2006-02-22 20:17           ` Ravikiran G Thirumalai
2006-02-22 20:50             ` Andrew Morton
     [not found]               ` <20060223015144.GC3663@localhost.localdomain>
2006-02-23  2:08                 ` Ravikiran G Thirumalai
2006-02-21 20:20   ` Ravikiran G Thirumalai
2006-02-22  0:45     ` Nick Piggin
2006-02-22  2:09       ` Andrew Morton

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