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authorZachary Amsden <zach@vmware.com>2006-01-06 00:11:47 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-06 08:33:33 -0800
commit7c4cb60e5b97677424e95baee9c29df54b26e6ba (patch)
treea2ad6e6104e153d15bc4bfbb67f74b0e05fea03c /arch/i386/kernel/apm.c
parent599a6e8ca4ff7f453f847217ecc2718d68e3b0f6 (diff)
[PATCH] x86: GDT alignment fix
Make GDT page aligned and page padded to support running inside of a hypervisor. This prevents false sharing of the GDT page with other hot data, which is not allowed in Xen, and causes performance problems in VMware. Rather than go back to the old method of statically allocating the GDT (which wastes unneded space for non-present CPUs), the GDT for APs is allocated dynamically. Signed-off-by: Zachary Amsden <zach@vmware.com> Cc: "Seth, Rohit" <rohit.seth@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/kernel/apm.c')
-rw-r--r--arch/i386/kernel/apm.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c
index 1e60acbed3c..6c8e483ce9e 100644
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.c
@@ -2317,6 +2317,8 @@ static int __init apm_init(void)
for (i = 0; i < NR_CPUS; i++) {
struct desc_struct *gdt = get_cpu_gdt_table(i);
+ if (!gdt)
+ continue;
set_base(gdt[APM_CS >> 3],
__va((unsigned long)apm_info.bios.cseg << 4));
set_base(gdt[APM_CS_16 >> 3],