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Date: Thu, 29 May 2008 10:58:19 +0200
From: Jens Axboe <jens.axboe@...cle.com>
To: linux-kernel@...r.kernel.org
Cc: peterz@...radead.org, npiggin@...e.de, linux-arch@...r.kernel.org,
jeremy@...p.org, mingo@...e.hu, paulmck@...ux.vnet.ibm.com,
Jens Axboe <jens.axboe@...cle.com>
Subject: [PATCH 5/10] alpha: convert to generic helpers for IPI function calls
This converts alpha to use the new helpers for smp_call_function() and
friends, and adds support for smp_call_function_single().
Signed-off-by: Jens Axboe <jens.axboe@...cle.com>
---
arch/alpha/Kconfig | 1 +
arch/alpha/kernel/core_marvel.c | 6 +-
arch/alpha/kernel/smp.c | 170 +++------------------------------------
include/asm-alpha/smp.h | 2 -
4 files changed, 14 insertions(+), 165 deletions(-)
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 729cdbd..dbe8c28 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -528,6 +528,7 @@ config ARCH_MAY_HAVE_PC_FDC
config SMP
bool "Symmetric multi-processing support"
depends on ALPHA_SABLE || ALPHA_LYNX || ALPHA_RAWHIDE || ALPHA_DP264 || ALPHA_WILDFIRE || ALPHA_TITAN || ALPHA_GENERIC || ALPHA_SHARK || ALPHA_MARVEL
+ select USE_GENERIC_SMP_HELPERS
---help---
This enables support for systems with more than one CPU. If you have
a system with only one CPU, like most personal computers, say N. If
diff --git a/arch/alpha/kernel/core_marvel.c b/arch/alpha/kernel/core_marvel.c
index b04f1fe..ced4aae 100644
--- a/arch/alpha/kernel/core_marvel.c
+++ b/arch/alpha/kernel/core_marvel.c
@@ -660,9 +660,9 @@ __marvel_rtc_io(u8 b, unsigned long addr, int write)
#ifdef CONFIG_SMP
if (smp_processor_id() != boot_cpuid)
- smp_call_function_on_cpu(__marvel_access_rtc,
- &rtc_access, 1, 1,
- cpumask_of_cpu(boot_cpuid));
+ smp_call_function_single(boot_cpuid,
+ __marvel_access_rtc,
+ &rtc_access, 1, 1);
else
__marvel_access_rtc(&rtc_access);
#else
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 2525692..95c905b 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -62,6 +62,7 @@ static struct {
enum ipi_message_type {
IPI_RESCHEDULE,
IPI_CALL_FUNC,
+ IPI_CALL_FUNC_SINGLE,
IPI_CPU_STOP,
};
@@ -558,51 +559,6 @@ send_ipi_message(cpumask_t to_whom, enum ipi_message_type operation)
wripir(i);
}
-/* Structure and data for smp_call_function. This is designed to
- minimize static memory requirements. Plus it looks cleaner. */
-
-struct smp_call_struct {
- void (*func) (void *info);
- void *info;
- long wait;
- atomic_t unstarted_count;
- atomic_t unfinished_count;
-};
-
-static struct smp_call_struct *smp_call_function_data;
-
-/* Atomicly drop data into a shared pointer. The pointer is free if
- it is initially locked. If retry, spin until free. */
-
-static int
-pointer_lock (void *lock, void *data, int retry)
-{
- void *old, *tmp;
-
- mb();
- again:
- /* Compare and swap with zero. */
- asm volatile (
- "1: ldq_l %0,%1\n"
- " mov %3,%2\n"
- " bne %0,2f\n"
- " stq_c %2,%1\n"
- " beq %2,1b\n"
- "2:"
- : "=&r"(old), "=m"(*(void **)lock), "=&r"(tmp)
- : "r"(data)
- : "memory");
-
- if (old == 0)
- return 0;
- if (! retry)
- return -EBUSY;
-
- while (*(void **)lock)
- barrier();
- goto again;
-}
-
void
handle_ipi(struct pt_regs *regs)
{
@@ -632,31 +588,12 @@ handle_ipi(struct pt_regs *regs)
break;
case IPI_CALL_FUNC:
- {
- struct smp_call_struct *data;
- void (*func)(void *info);
- void *info;
- int wait;
-
- data = smp_call_function_data;
- func = data->func;
- info = data->info;
- wait = data->wait;
-
- /* Notify the sending CPU that the data has been
- received, and execution is about to begin. */
- mb();
- atomic_dec (&data->unstarted_count);
-
- /* At this point the structure may be gone unless
- wait is true. */
- (*func)(info);
-
- /* Notify the sending CPU that the task is done. */
- mb();
- if (wait) atomic_dec (&data->unfinished_count);
+ generic_smp_call_function_interrupt();
+ break;
+
+ case IPI_CALL_FUNC_SINGLE:
+ generic_smp_call_function_single_interrupt();
break;
- }
case IPI_CPU_STOP:
halt();
@@ -700,102 +637,15 @@ smp_send_stop(void)
send_ipi_message(to_whom, IPI_CPU_STOP);
}
-/*
- * Run a function on all other CPUs.
- * <func> The function to run. This must be fast and non-blocking.
- * <info> An arbitrary pointer to pass to the function.
- * <retry> If true, keep retrying until ready.
- * <wait> If true, wait 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 executed.
- * 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_on_cpu (void (*func) (void *info), void *info, int retry,
- int wait, cpumask_t to_whom)
+void arch_send_call_function_ipi(cpumask_t mask)
{
- struct smp_call_struct data;
- unsigned long timeout;
- int num_cpus_to_call;
-
- /* Can deadlock when called with interrupts disabled */
- WARN_ON(irqs_disabled());
-
- data.func = func;
- data.info = info;
- data.wait = wait;
-
- cpu_clear(smp_processor_id(), to_whom);
- num_cpus_to_call = cpus_weight(to_whom);
-
- atomic_set(&data.unstarted_count, num_cpus_to_call);
- atomic_set(&data.unfinished_count, num_cpus_to_call);
-
- /* Acquire the smp_call_function_data mutex. */
- if (pointer_lock(&smp_call_function_data, &data, retry))
- return -EBUSY;
-
- /* Send a message to the requested CPUs. */
- send_ipi_message(to_whom, IPI_CALL_FUNC);
-
- /* Wait for a minimal response. */
- timeout = jiffies + HZ;
- while (atomic_read (&data.unstarted_count) > 0
- && time_before (jiffies, timeout))
- barrier();
-
- /* If there's no response yet, log a message but allow a longer
- * timeout period -- if we get a response this time, log
- * a message saying when we got it..
- */
- if (atomic_read(&data.unstarted_count) > 0) {
- long start_time = jiffies;
- printk(KERN_ERR "%s: initial timeout -- trying long wait\n",
- __func__);
- timeout = jiffies + 30 * HZ;
- while (atomic_read(&data.unstarted_count) > 0
- && time_before(jiffies, timeout))
- barrier();
- if (atomic_read(&data.unstarted_count) <= 0) {
- long delta = jiffies - start_time;
- printk(KERN_ERR
- "%s: response %ld.%ld seconds into long wait\n",
- __func__, delta / HZ,
- (100 * (delta - ((delta / HZ) * HZ))) / HZ);
- }
- }
-
- /* We either got one or timed out -- clear the lock. */
- mb();
- smp_call_function_data = NULL;
-
- /*
- * If after both the initial and long timeout periods we still don't
- * have a response, something is very wrong...
- */
- BUG_ON(atomic_read (&data.unstarted_count) > 0);
-
- /* Wait for a complete response, if needed. */
- if (wait) {
- while (atomic_read (&data.unfinished_count) > 0)
- barrier();
- }
-
- return 0;
+ send_ipi_message(mask, IPI_CALL_FUNC);
}
-EXPORT_SYMBOL(smp_call_function_on_cpu);
-int
-smp_call_function (void (*func) (void *info), void *info, int retry, int wait)
+void arch_send_call_function_single_ipi(int cpu)
{
- return smp_call_function_on_cpu (func, info, retry, wait,
- cpu_online_map);
+ send_ipi_message(cpumask_of_cpu(cpu), IPI_CALL_FUNC_SINGLE);
}
-EXPORT_SYMBOL(smp_call_function);
static void
ipi_imb(void *ignored)
diff --git a/include/asm-alpha/smp.h b/include/asm-alpha/smp.h
index 286e1d8..a9090b6 100644
--- a/include/asm-alpha/smp.h
+++ b/include/asm-alpha/smp.h
@@ -47,8 +47,6 @@ extern struct cpuinfo_alpha cpu_data[NR_CPUS];
extern int smp_num_cpus;
#define cpu_possible_map cpu_present_map
-int smp_call_function_on_cpu(void (*func) (void *info), void *info,int retry, int wait, cpumask_t cpu);
-
#else /* CONFIG_SMP */
#define hard_smp_processor_id() 0
--
1.5.6.rc0.40.gd683
--
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