[PATCH 08/12] generic: reduce stack pressure in sched_affinity
From: Mike Travis
Date: Fri Apr 04 2008 - 21:11:45 EST
* Modify sched_affinity functions to pass cpumask_t variables by reference
instead of by value.
* Use new set_cpus_allowed_ptr function.
Depends on:
[sched-devel]: sched: add new set_cpus_allowed_ptr function
Based on:
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
+ x86/latest .../x86/linux-2.6-x86.git
+ sched-devel/latest .../mingo/linux-2.6-sched-devel.git
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Paul Jackson <pj@xxxxxxx>
Cc: Cliff Wickman <cpw@xxxxxxx>
Signed-off-by: Mike Travis <travis@xxxxxxx>
---
arch/x86/kernel/cpu/mcheck/mce_amd_64.c | 46 ++++++++++++++++----------------
include/linux/sched.h | 2 -
kernel/compat.c | 2 -
kernel/rcupreempt.c | 4 +-
kernel/sched.c | 5 ++-
5 files changed, 30 insertions(+), 29 deletions(-)
--- linux-2.6.x86.orig/arch/x86/kernel/cpu/mcheck/mce_amd_64.c
+++ linux-2.6.x86/arch/x86/kernel/cpu/mcheck/mce_amd_64.c
@@ -251,18 +251,18 @@ struct threshold_attr {
ssize_t(*store) (struct threshold_block *, const char *, size_t count);
};
-static cpumask_t affinity_set(unsigned int cpu)
+static void affinity_set(unsigned int cpu, cpumask_t *oldmask,
+ cpumask_t *newmask)
{
- cpumask_t oldmask = current->cpus_allowed;
- cpumask_t newmask = CPU_MASK_NONE;
- cpu_set(cpu, newmask);
- set_cpus_allowed(current, newmask);
- return oldmask;
+ *oldmask = current->cpus_allowed;
+ cpus_clear(*newmask);
+ cpu_set(cpu, *newmask);
+ set_cpus_allowed_ptr(current, newmask);
}
-static void affinity_restore(cpumask_t oldmask)
+static void affinity_restore(const cpumask_t *oldmask)
{
- set_cpus_allowed(current, oldmask);
+ set_cpus_allowed_ptr(current, oldmask);
}
#define SHOW_FIELDS(name) \
@@ -277,15 +277,15 @@ static ssize_t store_interrupt_enable(st
const char *buf, size_t count)
{
char *end;
- cpumask_t oldmask;
+ cpumask_t oldmask, newmask;
unsigned long new = simple_strtoul(buf, &end, 0);
if (end == buf)
return -EINVAL;
b->interrupt_enable = !!new;
- oldmask = affinity_set(b->cpu);
+ affinity_set(b->cpu, &oldmask, &newmask);
threshold_restart_bank(b, 0, 0);
- affinity_restore(oldmask);
+ affinity_restore(&oldmask);
return end - buf;
}
@@ -294,7 +294,7 @@ static ssize_t store_threshold_limit(str
const char *buf, size_t count)
{
char *end;
- cpumask_t oldmask;
+ cpumask_t oldmask, newmask;
u16 old;
unsigned long new = simple_strtoul(buf, &end, 0);
if (end == buf)
@@ -306,9 +306,9 @@ static ssize_t store_threshold_limit(str
old = b->threshold_limit;
b->threshold_limit = new;
- oldmask = affinity_set(b->cpu);
+ affinity_set(b->cpu, &oldmask, &newmask);
threshold_restart_bank(b, 0, old);
- affinity_restore(oldmask);
+ affinity_restore(&oldmask);
return end - buf;
}
@@ -316,10 +316,10 @@ static ssize_t store_threshold_limit(str
static ssize_t show_error_count(struct threshold_block *b, char *buf)
{
u32 high, low;
- cpumask_t oldmask;
- oldmask = affinity_set(b->cpu);
+ cpumask_t oldmask, newmask;
+ affinity_set(b->cpu, &oldmask, &newmask);
rdmsr(b->address, low, high);
- affinity_restore(oldmask);
+ affinity_restore(&oldmask);
return sprintf(buf, "%x\n",
(high & 0xFFF) - (THRESHOLD_MAX - b->threshold_limit));
}
@@ -327,10 +327,10 @@ static ssize_t show_error_count(struct t
static ssize_t store_error_count(struct threshold_block *b,
const char *buf, size_t count)
{
- cpumask_t oldmask;
- oldmask = affinity_set(b->cpu);
+ cpumask_t oldmask, newmask;
+ affinity_set(b->cpu, &oldmask, &newmask);
threshold_restart_bank(b, 1, 0);
- affinity_restore(oldmask);
+ affinity_restore(&oldmask);
return 1;
}
@@ -468,7 +468,7 @@ static __cpuinit int threshold_create_ba
{
int i, err = 0;
struct threshold_bank *b = NULL;
- cpumask_t oldmask = CPU_MASK_NONE;
+ cpumask_t oldmask, newmask;
char name[32];
sprintf(name, "threshold_bank%i", bank);
@@ -519,10 +519,10 @@ static __cpuinit int threshold_create_ba
per_cpu(threshold_banks, cpu)[bank] = b;
- oldmask = affinity_set(cpu);
+ affinity_set(cpu, &oldmask, &newmask);
err = allocate_threshold_blocks(cpu, bank, 0,
MSR_IA32_MC0_MISC + bank * 4);
- affinity_restore(oldmask);
+ affinity_restore(&oldmask);
if (err)
goto out_free;
--- linux-2.6.x86.orig/include/linux/sched.h
+++ linux-2.6.x86/include/linux/sched.h
@@ -2086,7 +2086,7 @@ ftrace_special(unsigned long arg1, unsig
}
#endif
-extern long sched_setaffinity(pid_t pid, cpumask_t new_mask);
+extern long sched_setaffinity(pid_t pid, const cpumask_t *new_mask);
extern long sched_getaffinity(pid_t pid, cpumask_t *mask);
extern int sched_mc_power_savings, sched_smt_power_savings;
--- linux-2.6.x86.orig/kernel/compat.c
+++ linux-2.6.x86/kernel/compat.c
@@ -446,7 +446,7 @@ asmlinkage long compat_sys_sched_setaffi
if (retval)
return retval;
- return sched_setaffinity(pid, new_mask);
+ return sched_setaffinity(pid, &new_mask);
}
asmlinkage long compat_sys_sched_getaffinity(compat_pid_t pid, unsigned int len,
--- linux-2.6.x86.orig/kernel/rcupreempt.c
+++ linux-2.6.x86/kernel/rcupreempt.c
@@ -1005,10 +1005,10 @@ void __synchronize_sched(void)
if (sched_getaffinity(0, &oldmask) < 0)
oldmask = cpu_possible_map;
for_each_online_cpu(cpu) {
- sched_setaffinity(0, cpumask_of_cpu(cpu));
+ sched_setaffinity(0, &cpumask_of_cpu(cpu));
schedule();
}
- sched_setaffinity(0, oldmask);
+ sched_setaffinity(0, &oldmask);
}
EXPORT_SYMBOL_GPL(__synchronize_sched);
--- linux-2.6.x86.orig/kernel/sched.c
+++ linux-2.6.x86/kernel/sched.c
@@ -4963,9 +4963,10 @@ out_unlock:
return retval;
}
-long sched_setaffinity(pid_t pid, cpumask_t new_mask)
+long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
{
cpumask_t cpus_allowed;
+ cpumask_t new_mask = *in_mask;
struct task_struct *p;
int retval;
@@ -5046,7 +5047,7 @@ asmlinkage long sys_sched_setaffinity(pi
if (retval)
return retval;
- return sched_setaffinity(pid, new_mask);
+ return sched_setaffinity(pid, &new_mask);
}
/*
--
--
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