bitkeeper revision 1.1159.1.372 (418a4933U-ePgadykH4jLP5wYenz0Q)

Merge freefall.cl.cam.ac.uk:/auto/groups/xeno/BK/xeno.bk
into freefall.cl.cam.ac.uk:/local/scratch/kaf24/xeno

5 files changed, 19 insertions, 137 deletions

diff --git a/.rootkeys b/.rootkeys
index d473cbcfe2..bd87779e78 100644
--- a/.rootkeys
+++ b/.rootkeys
@@ -176,7 +176,6 @@
 40f56238xFQe9T7M_U_FItM-bZIpLw linux-2.6.9-xen-sparse/arch/xen/kernel/evtchn.c
 4110f478aeQWllIN7J4kouAHiAqrPw linux-2.6.9-xen-sparse/arch/xen/kernel/fixup.c
 412dfae9eA3_6e6bCGUtg1mj8b56fQ linux-2.6.9-xen-sparse/arch/xen/kernel/gnttab.c
-40f56239sFcjHiIRmnObRIDF-zaeKQ linux-2.6.9-xen-sparse/arch/xen/kernel/process.c
 40f562392LBhwmOxVPsYdkYXMxI_ZQ linux-2.6.9-xen-sparse/arch/xen/kernel/reboot.c
 414c113396tK1HTVeUalm3u-1DF16g linux-2.6.9-xen-sparse/arch/xen/kernel/skbuff.c
 3f68905c5eiA-lBMQSvXLMWS1ikDEA linux-2.6.9-xen-sparse/arch/xen/kernel/xen_proc.c
diff --git a/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/process.c b/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/process.c
index a278f8aa39..1552e00db7 100644
--- a/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/process.c
+++ b/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/process.c
@@ -86,50 +86,25 @@ void enable_hlt(void)
 
 EXPORT_SYMBOL(enable_hlt);
 
-/*
- * We use this if we don't have any better
- * idle routine..
- */
-void default_idle(void)
+/* XXX XEN doesn't use default_idle(), poll_idle(). Use xen_idle() instead. */
+extern int set_timeout_timer(void);
+void xen_idle(void)
 {
-	if (!hlt_counter && current_cpu_data.hlt_works_ok) {
-		local_irq_disable();
-		if (!need_resched())
-			safe_halt();
-		else
-			local_irq_enable();
-	}
-}
+	int cpu = smp_processor_id();
 
-/*
- * On SMP it's slightly faster (but much more power-consuming!)
- * to poll the ->work.need_resched flag instead of waiting for the
- * cross-CPU IPI to arrive. Use this option with caution.
- */
-static void poll_idle (void)
-{
-	int oldval;
+	local_irq_disable();
 
-	local_irq_enable();
+	if (rcu_pending(cpu))
+		rcu_check_callbacks(cpu, 0);
 
-	/*
-	 * Deal with another CPU just having chosen a thread to
-	 * run here:
-	 */
-	oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
-
-	if (!oldval) {
-		set_thread_flag(TIF_POLLING_NRFLAG);
-		asm volatile(
-			"2:"
-			"testl %0, %1;"
-			"rep; nop;"
-			"je 2b;"
-			: : "i"(_TIF_NEED_RESCHED), "m" (current_thread_info()->flags));
-
-		clear_thread_flag(TIF_POLLING_NRFLAG);
+	if (need_resched()) {
+		local_irq_enable();
+	} else if (set_timeout_timer() == 0) {
+		/* NB. Blocking reenable events in a race-free manner. */
+		HYPERVISOR_block();
 	} else {
-		set_need_resched();
+		local_irq_enable();
+		HYPERVISOR_yield();
 	}
 }
 
@@ -144,82 +119,23 @@ void cpu_idle (void)
 	/* endless idle loop with no priority at all */
 	while (1) {
 		while (!need_resched()) {
-			void (*idle)(void);
 			/*
 			 * Mark this as an RCU critical section so that
 			 * synchronize_kernel() in the unload path waits
 			 * for our completion.
 			 */
 			rcu_read_lock();
-			idle = pm_idle;
-
-			if (!idle)
-				idle = default_idle;
-
 			irq_stat[smp_processor_id()].idle_timestamp = jiffies;
-			idle();
+			xen_idle();
 			rcu_read_unlock();
 		}
 		schedule();
 	}
 }
 
-/*
- * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
- * which can obviate IPI to trigger checking of need_resched.
- * We execute MONITOR against need_resched and enter optimized wait state
- * through MWAIT. Whenever someone changes need_resched, we would be woken
- * up from MWAIT (without an IPI).
- */
-static void mwait_idle(void)
-{
-	local_irq_enable();
-
-	if (!need_resched()) {
-		set_thread_flag(TIF_POLLING_NRFLAG);
-		do {
-			__monitor((void *)&current_thread_info()->flags, 0, 0);
-			if (need_resched())
-				break;
-			__mwait(0, 0);
-		} while (!need_resched());
-		clear_thread_flag(TIF_POLLING_NRFLAG);
-	}
-}
-
-void __init select_idle_routine(const struct cpuinfo_x86 *c)
-{
-	if (cpu_has(c, X86_FEATURE_MWAIT)) {
-		printk("monitor/mwait feature present.\n");
-		/*
-		 * Skip, if setup has overridden idle.
-		 * One CPU supports mwait => All CPUs supports mwait
-		 */
-		if (!pm_idle) {
-			printk("using mwait in idle threads.\n");
-			pm_idle = mwait_idle;
-		}
-	}
-}
-
-static int __init idle_setup (char *str)
-{
-	if (!strncmp(str, "poll", 4)) {
-		printk("using polling idle threads.\n");
-		pm_idle = poll_idle;
-#ifdef CONFIG_X86_SMP
-		if (smp_num_siblings > 1)
-			printk("WARNING: polling idle and HT enabled, performance may degrade.\n");
-#endif
-	} else if (!strncmp(str, "halt", 4)) {
-		printk("using halt in idle threads.\n");
-		pm_idle = default_idle;
-	}
-
-	return 1;
-}
-
-__setup("idle=", idle_setup);
+/* XXX XEN doesn't use mwait_idle(), select_idle_routine(), idle_setup(). */
+/* Always use xen_idle() instead. */
+void __init select_idle_routine(const struct cpuinfo_x86 *c) {}
 
 void show_regs(struct pt_regs * regs)
 {
diff --git a/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/setup.c b/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/setup.c
index 68a8f46b09..e10a0aaf97 100644
--- a/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/setup.c
+++ b/linux-2.6.9-xen-sparse/arch/xen/i386/kernel/setup.c
@@ -350,8 +350,6 @@ int nr_multicall_ents = 0;
 /* Raw start-of-day parameters from the hypervisor. */
 union xen_start_info_union xen_start_info_union;
 
-extern void (*pm_idle)(void);
-
 static void __init limit_regions(unsigned long long size)
 {
 	unsigned long long current_addr = 0;
@@ -1324,8 +1322,6 @@ void __init setup_arch(char **cmdline_p)
 	HYPERVISOR_vm_assist(VMASST_CMD_enable,
 			     VMASST_TYPE_4gb_segments);
 
-	pm_idle = xen_cpu_idle;
-
 	memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
 	early_cpu_init();
 
diff --git a/linux-2.6.9-xen-sparse/arch/xen/kernel/Makefile b/linux-2.6.9-xen-sparse/arch/xen/kernel/Makefile
index 3768ed261f..eef477fe3e 100644
--- a/linux-2.6.9-xen-sparse/arch/xen/kernel/Makefile
+++ b/linux-2.6.9-xen-sparse/arch/xen/kernel/Makefile
@@ -9,5 +9,5 @@ $(obj)/vmlinux.lds:
 
 extra-y += vmlinux.lds
 
-obj-y	:= ctrl_if.o evtchn.o fixup.o process.o reboot.o xen_proc.o empty.o \
+obj-y	:= ctrl_if.o evtchn.o fixup.o reboot.o xen_proc.o empty.o \
            gnttab.o skbuff.o
diff --git a/linux-2.6.9-xen-sparse/arch/xen/kernel/process.c b/linux-2.6.9-xen-sparse/arch/xen/kernel/process.c
deleted file mode 100644
index 3a0c620dd6..0000000000
--- a/linux-2.6.9-xen-sparse/arch/xen/kernel/process.c
+++ /dev/null
@@ -1,29 +0,0 @@
-
-#include <stdarg.h>
-
-#include <linux/errno.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/platform.h>
-#include <linux/pm.h>
-#include <linux/rcupdate.h>
-
-extern int set_timeout_timer(void);
-
-void xen_cpu_idle (void)
-{
-	struct rcu_data *rdp = &__get_cpu_var(rcu_bh_data);
-
-	local_irq_disable();
-	if (need_resched() || rdp->curlist) {
-		local_irq_enable();
-		return;
-	}
-	if (set_timeout_timer() == 0) {
-		/* NB. Blocking reenable events in a race-free manner. */
-		HYPERVISOR_block();
-		return;
-	}
-	local_irq_enable();
-	HYPERVISOR_yield();
-}