[Xen-devel] [patch 10/34] Xen-pv_ops: Simplify smp_call_function*() by using common implementation

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

smp_call_function and smp_call_function_single are almost complete
duplicates of the same logic.  This patch combines them by
implementing them in terms of the more general
smp_call_function_mask().

Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Cc: "Randy.Dunlap" <rdunlap@xxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>

---
 arch/i386/kernel/smp.c |  213 ++++++++++++++++++++++--------------------------
 1 file changed, 102 insertions(+), 111 deletions(-)

===================================================================
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -515,6 +515,73 @@ void unlock_ipi_call_lock(void)
 
 static struct call_data_struct *call_data;
 
+
+/**
+ * smp_call_function_mask(): Run a function on a set of other CPUs.
+ * @mask: The set of cpus to run on.  Must not include the current cpu.
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @wait: If true, wait (atomically) until function has completed on other 
CPUs.
+ *
+ * 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 finished.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler.
+ */
+int smp_call_function_mask(cpumask_t mask,
+                          void (*func)(void *), void *info,
+                          int wait)
+{
+       struct call_data_struct data;
+       cpumask_t allbutself;
+       int cpus;
+
+       /* Can deadlock when called with interrupts disabled */
+       WARN_ON(irqs_disabled());
+
+       /* Holding any lock stops cpus from going down. */
+       spin_lock(&call_lock);
+
+       allbutself = cpu_online_map;
+       cpu_clear(smp_processor_id(), allbutself);
+
+       cpus_and(mask, mask, allbutself);
+       cpus = cpus_weight(mask);
+
+       if (!cpus) {
+               spin_unlock(&call_lock);
+               return 0;
+       }
+
+       data.func = func;
+       data.info = info;
+       atomic_set(&data.started, 0);
+       data.wait = wait;
+       if (wait)
+               atomic_set(&data.finished, 0);
+
+       call_data = &data;
+       mb();
+
+       /* Send a message to other CPUs */
+       if (cpus_equal(mask, allbutself))
+               send_IPI_allbutself(CALL_FUNCTION_VECTOR);
+       else
+               send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
+
+       /* Wait for response */
+       while (atomic_read(&data.started) != cpus)
+               cpu_relax();
+
+       if (wait)
+               while (atomic_read(&data.finished) != cpus)
+                       cpu_relax();
+       spin_unlock(&call_lock);
+
+       return 0;
+}
+
 /**
  * smp_call_function(): Run a function on all other CPUs.
  * @func: The function to run. This must be fast and non-blocking.
@@ -528,48 +595,43 @@ static struct call_data_struct *call_dat
  * You must not call this function with disabled interrupts or from a
  * hardware interrupt handler or from a bottom half handler.
  */
-int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
-                       int wait)
-{
-       struct call_data_struct data;
-       int cpus;
-
-       /* Holding any lock stops cpus from going down. */
-       spin_lock(&call_lock);
-       cpus = num_online_cpus() - 1;
-       if (!cpus) {
-               spin_unlock(&call_lock);
-               return 0;
-       }
-
-       /* Can deadlock when called with interrupts disabled */
-       WARN_ON(irqs_disabled());
-
-       data.func = func;
-       data.info = info;
-       atomic_set(&data.started, 0);
-       data.wait = wait;
-       if (wait)
-               atomic_set(&data.finished, 0);
-
-       call_data = &data;
-       mb();
-       
-       /* Send a message to all other CPUs and wait for them to respond */
-       send_IPI_allbutself(CALL_FUNCTION_VECTOR);
-
-       /* Wait for response */
-       while (atomic_read(&data.started) != cpus)
-               cpu_relax();
-
-       if (wait)
-               while (atomic_read(&data.finished) != cpus)
-                       cpu_relax();
-       spin_unlock(&call_lock);
-
-       return 0;
+int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
+                     int wait)
+{
+       return smp_call_function_mask(cpu_online_map, func, info, wait);
 }
 EXPORT_SYMBOL(smp_call_function);
+
+/*
+ * smp_call_function_single - Run a function on another CPU
+ * @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 until function has completed on other CPUs.
+ *
+ * Retrurns 0 on success, else a negative status code.
+ *
+ * Does not return until the remote CPU is nearly ready to execute <func>
+ * or is or has executed.
+ */
+int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
+                            int nonatomic, int wait)
+{
+       /* prevent preemption and reschedule on another processor */
+       int ret;
+       int me = get_cpu();
+       if (cpu == me) {
+               WARN_ON(1);
+               put_cpu();
+               return -EBUSY;
+       }
+
+       ret = smp_call_function_mask(cpumask_of_cpu(cpu), func, info, wait);
+
+       put_cpu();
+       return ret;
+}
+EXPORT_SYMBOL(smp_call_function_single);
 
 static void stop_this_cpu (void * dummy)
 {
@@ -633,77 +695,6 @@ fastcall void smp_call_function_interrup
        }
 }
 
-/*
- * this function sends a 'generic call function' IPI to one other CPU
- * in the system.
- *
- * cpu is a standard Linux logical CPU number.
- */
-static void
-__smp_call_function_single(int cpu, void (*func) (void *info), void *info,
-                               int nonatomic, int wait)
-{
-       struct call_data_struct data;
-       int cpus = 1;
-
-       data.func = func;
-       data.info = info;
-       atomic_set(&data.started, 0);
-       data.wait = wait;
-       if (wait)
-               atomic_set(&data.finished, 0);
-
-       call_data = &data;
-       wmb();
-       /* Send a message to all other CPUs and wait for them to respond */
-       send_IPI_mask(cpumask_of_cpu(cpu), CALL_FUNCTION_VECTOR);
-
-       /* Wait for response */
-       while (atomic_read(&data.started) != cpus)
-               cpu_relax();
-
-       if (!wait)
-               return;
-
-       while (atomic_read(&data.finished) != cpus)
-               cpu_relax();
-}
-
-/*
- * smp_call_function_single - Run a function on another CPU
- * @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 until function has completed on other CPUs.
- *
- * Retrurns 0 on success, else a negative status code.
- *
- * Does not return until the remote CPU is nearly ready to execute <func>
- * or is or has executed.
- */
-
-int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
-                       int nonatomic, int wait)
-{
-       /* prevent preemption and reschedule on another processor */
-       int me = get_cpu();
-       if (cpu == me) {
-               WARN_ON(1);
-               put_cpu();
-               return -EBUSY;
-       }
-
-       /* Can deadlock when called with interrupts disabled */
-       WARN_ON(irqs_disabled());
-
-       spin_lock_bh(&call_lock);
-       __smp_call_function_single(cpu, func, info, nonatomic, wait);
-       spin_unlock_bh(&call_lock);
-       put_cpu();
-       return 0;
-}
-EXPORT_SYMBOL(smp_call_function_single);
-
 static int convert_apicid_to_cpu(int apic_id)
 {
        int i;

-- 


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel