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Subject[PATCH][2.5] smp_call_function_mask
This patch adds a smp_call_function which also accepts a cpu mask which is 
needed for targetting specific or groups of cpus.

Index: linux-2.5.58-cpu_hotplug/arch/i386/kernel/smp.c
===================================================================
RCS file: /build/cvsroot/linux-2.5.58/arch/i386/kernel/smp.c,v
retrieving revision 1.1.1.1
retrieving revision 1.2
diff -u -r1.1.1.1 -r1.2
--- linux-2.5.58-cpu_hotplug/arch/i386/kernel/smp.c 14 Jan 2003 06:59:22 -0000 1.1.1.1
+++ linux-2.5.58-cpu_hotplug/arch/i386/kernel/smp.c 15 Jan 2003 07:59:32 -0000 1.2
@@ -544,6 +544,57 @@
return 0;
}

+int smp_call_function_mask (void (*func) (void *info), void *info, int nonatomic,
+ int wait, unsigned long mask)
+/*
+ * [SUMMARY] Run a function on specific CPUs, save self.
+ * <func> The function to run. This must be fast and non-blocking.
+ * <info> An arbitrary pointer to pass to the function.
+ * <nonatomic> currently unused.
+ * <wait> If true, wait (atomically) until function has completed on other CPUs.
+ * <mask> The bitmask of CPUs to call the function
+ * [RETURNS] 0 on success, else a negative status code. Does not return until
+ * remote CPUs are nearly ready to execute <<func>> or are or have executed.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler.
+ */
+{
+ struct call_data_struct data;
+ int num_cpus = hweight32(mask);
+
+ if (num_cpus == 0)
+ return -EINVAL;
+
+ if ((1UL << smp_processor_id()) & mask)
+ return -EINVAL;
+
+ data.func = func;
+ data.info = info;
+ atomic_set(&data.started, 0);
+ data.wait = wait;
+ if (wait)
+ atomic_set(&data.finished, 0);
+
+ spin_lock(&call_lock);
+ call_data = &data;
+ wmb();
+
+ /* Send a message to the CPUs in the mask and wait for them to respond */
+ send_IPI_mask_sequence(mask, CALL_FUNCTION_VECTOR);
+
+ /* Wait for response */
+ while (atomic_read(&data.started) != num_cpus)
+ barrier();
+
+ if (wait)
+ while (atomic_read(&data.finished) != num_cpus)
+ barrier();
+ spin_unlock(&call_lock);
+
+ return 0;
+}
+
static void stop_this_cpu (void * dummy)
{
/*
Index: linux-2.5.58-cpu_hotplug/include/linux/smp.h
===================================================================
RCS file: /build/cvsroot/linux-2.5.58/include/linux/smp.h,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 smp.h
--- linux-2.5.58-cpu_hotplug/include/linux/smp.h 14 Jan 2003 07:02:19 -0000 1.1.1.1
+++ linux-2.5.58-cpu_hotplug/include/linux/smp.h 15 Jan 2003 08:13:35 -0000
@@ -53,6 +53,9 @@
extern int smp_call_function (void (*func) (void *info), void *info,
int retry, int wait);

+extern int smp_call_function_mask (void (*func) (void *info), void *info,
+ int retry, int wait, unsigned long mask);
+
/*
* True once the per process idle is forked
*/
@@ -96,6 +99,7 @@
#define hard_smp_processor_id() 0
#define smp_threads_ready 1
#define smp_call_function(func,info,retry,wait) ({ 0; })
+#define smp_call_function_mask(func,info,retry,wait,mask) ({ 0; })
static inline void smp_send_reschedule(int cpu) { }
static inline void smp_send_reschedule_all(void) { }
#define cpu_online_map 1
--
function.linuxpower.ca

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