lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

[IA64] Optional method to purge the TLB on SN systems

Browse Source 
This patch adds an optional method for purging the TLB on SN IA64 systems.
The change should not affect any non-SN system.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Jack Steiner
2007-05-08 14:50:43 -07:00
committed by Tony Luck
parent 8737d59579
commit 3be44b9cc3
5 changed files with 162 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

68
arch/ia64/kernel/smp.c
View File

@@ -49,6 +49,18 @@
#include <asm/unistd.h>
#include <asm/mca.h>
/*
* Note: alignment of 4 entries/cacheline was empirically determined
* to be a good tradeoff between hot cachelines & spreading the array
* across too many cacheline.
*/
static struct local_tlb_flush_counts {
unsigned int count;
} __attribute__((__aligned__(32))) local_tlb_flush_counts[NR_CPUS];
static DEFINE_PER_CPU(unsigned int, shadow_flush_counts[NR_CPUS]) ____cacheline_aligned;
/*
* Structure and data for smp_call_function(). This is designed to minimise static memory
* requirements. It also looks cleaner.
@@ -248,6 +260,62 @@ smp_send_reschedule (int cpu)
platform_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
}
/*
* Called with preeemption disabled.
*/
static void
smp_send_local_flush_tlb (int cpu)
{
platform_send_ipi(cpu, IA64_IPI_LOCAL_TLB_FLUSH, IA64_IPI_DM_INT, 0);
}
void
smp_local_flush_tlb(void)
{
/*
* Use atomic ops. Otherwise, the load/increment/store sequence from
* a "++" operation can have the line stolen between the load & store.
* The overhead of the atomic op in negligible in this case & offers
* significant benefit for the brief periods where lots of cpus
* are simultaneously flushing TLBs.
*/
ia64_fetchadd(1, &local_tlb_flush_counts[smp_processor_id()].count, acq);
local_flush_tlb_all();
}
#define FLUSH_DELAY 5 /* Usec backoff to eliminate excessive cacheline bouncing */
void
smp_flush_tlb_cpumask(cpumask_t xcpumask)
{
unsigned int *counts = __ia64_per_cpu_var(shadow_flush_counts);
cpumask_t cpumask = xcpumask;
int mycpu, cpu, flush_mycpu = 0;
preempt_disable();
mycpu = smp_processor_id();
for_each_cpu_mask(cpu, cpumask)
counts[cpu] = local_tlb_flush_counts[cpu].count;
mb();
for_each_cpu_mask(cpu, cpumask) {
if (cpu == mycpu)
flush_mycpu = 1;
else
smp_send_local_flush_tlb(cpu);
}
if (flush_mycpu)
smp_local_flush_tlb();
for_each_cpu_mask(cpu, cpumask)
while(counts[cpu] == local_tlb_flush_counts[cpu].count)
udelay(FLUSH_DELAY);
preempt_enable();
}
void
smp_flush_tlb_all (void)
{