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Subject[PATCH] cpu_mask_t
Date
And this is part II.  Each arch implements cpu_mask_t, cpu_online_mask(&res,
mask), CPU_MASK_ALL, CPU_MASK_NONE, and we're done.

Boots, runs.

Name: CPU mask patch
Author: Rusty Russell
Status: Trivial
Depends: Hotcpu/migrate-to-cpu.patch.gz

D: This patch adds a cpu_mask_t for easy future expansion of cpu masks.
D: It also changes any_online_cpu to return NR_CPUS on failure, like
D: find_first_bit.

diff -urpN -I $.*$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.25.30219/include/asm-i386/smp.h linux-2.5.25.30219.updated/include/asm-i386/smp.h
--- linux-2.5.25.30219/include/asm-i386/smp.h Thu Jun 20 01:28:51 2002
+++ linux-2.5.25.30219.updated/include/asm-i386/smp.h Tue Jul 16 17:18:55 2002
@@ -99,14 +99,6 @@ extern inline unsigned int num_online_cp
return hweight32(cpu_online_map);
}

-extern inline int any_online_cpu(unsigned int mask)
-{
- if (mask & cpu_online_map)
- return __ffs(mask & cpu_online_map);
-
- return -1;
-}
-
static __inline int hard_smp_processor_id(void)
{
/* we don't want to mark this access volatile - bad code generation */
@@ -117,6 +109,23 @@ static __inline int logical_smp_processo
{
/* we don't want to mark this access volatile - bad code generation */
return GET_APIC_LOGICAL_ID(*(unsigned long *)(APIC_BASE+APIC_LDR));
+}
+
+/* This has to be bitop capable, so for most archs, an unsigned long */
+typedef unsigned long cpu_mask_t;
+#define CPU_MASK_ALL (~0UL)
+#define CPU_MASK_NONE (0UL)
+
+static inline void cpu_online_mask(cpu_mask_t *res, cpu_mask_t mask)
+{
+ *res = (mask & cpu_online_map);
+}
+
+static inline unsigned int any_online_cpu(cpu_mask_t mask)
+{
+ if (mask & cpu_online_map)
+ return __ffs(mask & cpu_online_map);
+ return NR_CPUS;
}

#endif /* !__ASSEMBLY__ */
diff -urpN -I $.*$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.25.30219/include/asm-ia64/smp.h linux-2.5.25.30219.updated/include/asm-ia64/smp.h
--- linux-2.5.25.30219/include/asm-ia64/smp.h Thu Jun 20 01:28:51 2002
+++ linux-2.5.25.30219.updated/include/asm-ia64/smp.h Tue Jul 16 17:18:55 2002
@@ -51,12 +51,22 @@ extern inline unsigned int num_online_cp
return hweight64(cpu_online_map);
}

-extern inline int any_online_cpu(unsigned int mask)
+/* This has to be bitop capable, so for most archs, an unsigned long */
+typedef unsigned long cpu_mask_t;
+#define CPU_MASK_ALL (~0UL)
+#define CPU_MASK_NONE (0UL)
+
+static inline void cpu_online_mask(cpu_mask_t *res, cpu_mask_t mask)
+{
+ *res = (mask & cpu_online_map);
+}
+
+static inline unsigned int any_online_cpu(cpu_mask_t mask)
{
if (mask & cpu_online_map)
return __ffs(mask & cpu_online_map);

- return -1;
+ return NR_CPUS;
}

/*
diff -urpN -I $.*$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.25.30219/include/asm-ppc/smp.h linux-2.5.25.30219.updated/include/asm-ppc/smp.h
--- linux-2.5.25.30219/include/asm-ppc/smp.h Thu Jun 20 01:28:51 2002
+++ linux-2.5.25.30219.updated/include/asm-ppc/smp.h Tue Jul 16 17:18:55 2002
@@ -54,12 +54,21 @@ extern inline unsigned int num_online_cp
return hweight32(cpu_online_map);
}

-extern inline int any_online_cpu(unsigned int mask)
+typedef unsigned long cpu_mask_t;
+#define CPU_MASK_ALL (~0UL)
+#define CPU_MASK_NONE (0UL)
+
+static inline void cpu_online_mask(cpu_mask_t *res, cpu_mask_t mask)
+{
+ *res = (mask & cpu_online_map);
+}
+
+static inline unsigned int any_online_cpu(cpu_mask_t mask)
{
if (mask & cpu_online_map)
return __ffs(mask & cpu_online_map);

- return -1;
+ return NR_CPUS;
}

extern int smp_hw_index[];
diff -urpN -I $.*$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.25.30219/include/linux/init_task.h linux-2.5.25.30219.updated/include/linux/init_task.h
--- linux-2.5.25.30219/include/linux/init_task.h Sun May 19 12:07:34 2002
+++ linux-2.5.25.30219.updated/include/linux/init_task.h Tue Jul 16 17:18:55 2002
@@ -48,7 +48,7 @@
prio: MAX_PRIO-20,
static_prio: MAX_PRIO-20,
policy: SCHED_OTHER,
- cpus_allowed: -1,
+ cpus_allowed: CPU_MASK_ALL,
mm: NULL,
active_mm: &init_mm,
run_list: LIST_HEAD_INIT(tsk.run_list),
diff -urpN -I $.*$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.25.30219/include/linux/sched.h linux-2.5.25.30219.updated/include/linux/sched.h
--- linux-2.5.25.30219/include/linux/sched.h Tue Jul 16 17:18:52 2002
+++ linux-2.5.25.30219.updated/include/linux/sched.h Tue Jul 16 17:18:55 2002
@@ -20,6 +20,7 @@ extern unsigned long event;
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/mmu.h>
+#include <asm/current.h>

#include <linux/smp.h>
#include <linux/sem.h>
@@ -263,7 +264,7 @@ struct task_struct {
unsigned long sleep_timestamp;

unsigned long policy;
- unsigned long cpus_allowed;
+ cpu_mask_t cpus_allowed;
unsigned int time_slice;

struct list_head tasks;
@@ -407,12 +408,12 @@ do { if (atomic_dec_and_test(&(tsk)->usa
#define _STK_LIM (8*1024*1024)

#if CONFIG_SMP
-extern void set_cpus_allowed(task_t *p, unsigned long new_mask);
+extern void set_cpus_allowed(task_t *p, cpu_mask_t new_mask);
static inline void migrate_to_cpu(unsigned int cpu)
{
- unsigned long mask = 0;
+ cpu_mask_t mask = CPU_MASK_NONE;
BUG_ON(!cpu_online(cpu));
- __set_bit(cpu, &mask);
+ __set_bit(cpu, (unsigned long *)&mask);
set_cpus_allowed(current, mask);
}
#else
@@ -483,8 +484,6 @@ static inline struct task_struct *find_t
/* per-UID process charging. */
extern struct user_struct * alloc_uid(uid_t);
extern void free_uid(struct user_struct *);
-
-#include <asm/current.h>

extern unsigned long itimer_ticks;
extern unsigned long itimer_next;
diff -urpN -I $.*$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.25.30219/include/linux/smp.h linux-2.5.25.30219.updated/include/linux/smp.h
--- linux-2.5.25.30219/include/linux/smp.h Fri Jun 21 09:41:55 2002
+++ linux-2.5.25.30219.updated/include/linux/smp.h Tue Jul 16 17:18:55 2002
@@ -86,13 +86,16 @@ extern volatile int smp_msg_id;
#define smp_call_function(func,info,retry,wait) ({ 0; })
static inline void smp_send_reschedule(int cpu) { }
static inline void smp_send_reschedule_all(void) { }
-#define cpu_online_map 1
#define cpu_online(cpu) 1
#define num_online_cpus() 1
#define __per_cpu_data
#define per_cpu(var, cpu) var
#define this_cpu(var) var
-
+typedef unsigned long cpu_mask_t;
+#define CPU_MASK_ALL 1
+#define CPU_MASK_NONE 0
+#define cpu_online_mask(res,mask) do { *(res) = ((mask) & 1); } while(0)
+#define any_online_cpu(mask) (((mask) & 1) ? 0 : 1)
#endif /* !SMP */

#define get_cpu() ({ preempt_disable(); smp_processor_id(); })
diff -urpN -I $.*$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.25.30219/kernel/sched.c linux-2.5.25.30219.updated/kernel/sched.c
--- linux-2.5.25.30219/kernel/sched.c Tue Jul 16 17:18:52 2002
+++ linux-2.5.25.30219.updated/kernel/sched.c Tue Jul 16 17:20:35 2002
@@ -367,7 +367,8 @@ repeat_lock_task:
*/
if (unlikely(sync && (rq->curr != p) &&
(task_cpu(p) != smp_processor_id()) &&
- (p->cpus_allowed & (1UL << smp_processor_id())))) {
+ test_bit(smp_processor_id(),
+ (unsigned long *)&p->cpus_allowed))) {

set_task_cpu(p, smp_processor_id());
task_rq_unlock(rq, &flags);
@@ -647,7 +648,7 @@ skip_queue:
#define CAN_MIGRATE_TASK(p,rq,this_cpu)
((jiffies - (p)->sleep_timestamp > cache_decay_ticks) &&
((p) != (rq)->curr) &&
- ((p)->cpus_allowed & (1UL << (this_cpu))))
+ (test_bit((this_cpu), (unsigned long *)&(p)->cpus_allowed)))

if (!CAN_MIGRATE_TASK(tmp, busiest, this_cpu)) {
curr = curr->next;
@@ -1319,7 +1320,7 @@ out_unlock:
asmlinkage int sys_sched_setaffinity(pid_t pid, unsigned int len,
unsigned long *user_mask_ptr)
{
- unsigned long new_mask;
+ cpu_mask_t online_mask, new_mask;
int retval;
task_t *p;

@@ -1329,8 +1330,8 @@ asmlinkage int sys_sched_setaffinity(pid
if (copy_from_user(&new_mask, user_mask_ptr, sizeof(new_mask)))
return -EFAULT;

- new_mask &= cpu_online_map;
- if (!new_mask)
+ cpu_online_mask(&online_mask, new_mask);
+ if (find_first_bit((unsigned long *)online_mask, NR_CPUS) == NR_CPUS)
return -EINVAL;

read_lock(&tasklist_lock);
@@ -1355,7 +1356,7 @@ asmlinkage int sys_sched_setaffinity(pid
goto out_unlock;

retval = 0;
- set_cpus_allowed(p, new_mask);
+ set_cpus_allowed(p, online_mask);

out_unlock:
put_task_struct(p);
@@ -1372,7 +1373,7 @@ asmlinkage int sys_sched_getaffinity(pid
unsigned long *user_mask_ptr)
{
unsigned int real_len;
- unsigned long mask;
+ cpu_mask_t mask;
int retval;
task_t *p;

@@ -1388,7 +1389,7 @@ asmlinkage int sys_sched_getaffinity(pid
goto out_unlock;

retval = 0;
- mask = p->cpus_allowed & cpu_online_map;
+ cpu_online_mask(&mask, p->cpus_allowed);

out_unlock:
read_unlock(&tasklist_lock);
@@ -1746,16 +1747,12 @@ typedef struct {
* task must not exit() & deallocate itself prematurely. The
* call is not atomic; no spinlocks may be held.
*/
-void set_cpus_allowed(task_t *p, unsigned long new_mask)
+void set_cpus_allowed(task_t *p, cpu_mask_t new_mask)
{
unsigned long flags;
migration_req_t req;
runqueue_t *rq;

- new_mask &= cpu_online_map;
- if (!new_mask)
- BUG();
-
preempt_disable();
rq = task_rq_lock(p, &flags);
p->cpus_allowed = new_mask;
@@ -1763,7 +1760,7 @@ void set_cpus_allowed(task_t *p, unsigne
* Can the task run on the task's current CPU? If not then
* migrate the process off to a proper CPU.
*/
- if (new_mask & (1UL << task_cpu(p))) {
+ if (test_bit(task_cpu(p), (unsigned long *)&new_mask)) {
task_rq_unlock(rq, &flags);
goto out;
}
@@ -1772,7 +1769,8 @@ void set_cpus_allowed(task_t *p, unsigne
* it is sufficient to simply update the task's cpu field.
*/
if (!p->array && (p != rq->curr)) {
- set_task_cpu(p, __ffs(p->cpus_allowed));
+ set_task_cpu(p, any_online_cpu(p->cpus_allowed));
+ BUG_ON(task_cpu(p) >= NR_CPUS);
task_rq_unlock(rq, &flags);
goto out;
}
@@ -1838,7 +1836,7 @@ static int migration_thread(void * bind_
spin_unlock_irqrestore(&rq->lock, flags);

p = req->task;
- cpu_dest = __ffs(p->cpus_allowed);
+ cpu_dest = any_online_cpu(p->cpus_allowed);
rq_dest = cpu_rq(cpu_dest);
repeat:
cpu_src = task_cpu(p);
@@ -1879,7 +1877,7 @@ void __init migration_init(void)
CLONE_FS | CLONE_FILES | CLONE_SIGNAL) < 0)
BUG();
}
- current->cpus_allowed = -1L;
+ current->cpus_allowed = CPU_MASK_ALL;

for (cpu = 0; cpu < NR_CPUS; cpu++) {
if (!cpu_online(cpu))
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
-
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