diff options
author | Tejun Heo <tj@kernel.org> | 2009-01-13 06:41:35 -0500 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2009-01-16 08:19:46 -0500 |
commit | 1a51e3a0aed18767cf2762e95456ecfeb0bca5e6 (patch) | |
tree | 2d930218ef1072a59f7dac0f97bb03aa02796c8c /arch/x86/xen | |
parent | c8f3329a0ddd751241e96b4100df7eda14b2cbc6 (diff) |
x86: fold pda into percpu area on SMP
[ Based on original patch from Christoph Lameter and Mike Travis. ]
Currently pdas and percpu areas are allocated separately. %gs points
to local pda and percpu area can be reached using pda->data_offset.
This patch folds pda into percpu area.
Due to strange gcc requirement, pda needs to be at the beginning of
the percpu area so that pda->stack_canary is at %gs:40. To achieve
this, a new percpu output section macro - PERCPU_VADDR_PREALLOC() - is
added and used to reserve pda sized chunk at the start of the percpu
area.
After this change, for boot cpu, %gs first points to pda in the
data.init area and later during setup_per_cpu_areas() gets updated to
point to the actual pda. This means that setup_per_cpu_areas() need
to reload %gs for CPU0 while clearing pda area for other cpus as cpu0
already has modified it when control reaches setup_per_cpu_areas().
This patch also removes now unnecessary get_local_pda() and its call
sites.
A lot of this patch is taken from Mike Travis' "x86_64: Fold pda into
per cpu area" patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r-- | arch/x86/xen/smp.c | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index c44e2069c7c7..83fa4236477d 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c | |||
@@ -283,16 +283,6 @@ static int __cpuinit xen_cpu_up(unsigned int cpu) | |||
283 | struct task_struct *idle = idle_task(cpu); | 283 | struct task_struct *idle = idle_task(cpu); |
284 | int rc; | 284 | int rc; |
285 | 285 | ||
286 | #ifdef CONFIG_X86_64 | ||
287 | /* Allocate node local memory for AP pdas */ | ||
288 | WARN_ON(cpu == 0); | ||
289 | if (cpu > 0) { | ||
290 | rc = get_local_pda(cpu); | ||
291 | if (rc) | ||
292 | return rc; | ||
293 | } | ||
294 | #endif | ||
295 | |||
296 | #ifdef CONFIG_X86_32 | 286 | #ifdef CONFIG_X86_32 |
297 | init_gdt(cpu); | 287 | init_gdt(cpu); |
298 | per_cpu(current_task, cpu) = idle; | 288 | per_cpu(current_task, cpu) = idle; |