Merge by hand (whitespace conflicts in libata.h)

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

9 files changed, 400 insertions, 235 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 3619e939182e..d61ba88f34e5 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -21,6 +21,24 @@ EXPORT_SYMBOL_GPL(cpucontrol);
 
 static struct notifier_block *cpu_chain;
 
+/*
+ * Used to check by callers if they need to acquire the cpucontrol
+ * or not to protect a cpu from being removed. Its sometimes required to
+ * call these functions both for normal operations, and in response to
+ * a cpu being added/removed. If the context of the call is in the same
+ * thread context as a CPU hotplug thread, we dont need to take the lock
+ * since its already protected
+ * check drivers/cpufreq/cpufreq.c for its usage - Ashok Raj
+ */
+
+int current_in_cpu_hotplug(void)
+{
+	return (current->flags & PF_HOTPLUG_CPU);
+}
+
+EXPORT_SYMBOL_GPL(current_in_cpu_hotplug);
+
+
 /* Need to know about CPUs going up/down? */
 int register_cpu_notifier(struct notifier_block *nb)
 {
@@ -94,6 +112,13 @@ int cpu_down(unsigned int cpu)
 		goto out;
 	}
 
+	/*
+	 * Leave a trace in current->flags indicating we are already in
+	 * process of performing CPU hotplug. Callers can check if cpucontrol
+	 * is already acquired by current thread, and if so not cause
+	 * a dead lock by not acquiring the lock
+	 */
+	current->flags |= PF_HOTPLUG_CPU;
 	err = notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
 						(void *)(long)cpu);
 	if (err == NOTIFY_BAD) {
@@ -146,6 +171,7 @@ out_thread:
 out_allowed:
 	set_cpus_allowed(current, old_allowed);
 out:
+	current->flags &= ~PF_HOTPLUG_CPU;
 	unlock_cpu_hotplug();
 	return err;
 }
@@ -163,6 +189,12 @@ int __devinit cpu_up(unsigned int cpu)
 		ret = -EINVAL;
 		goto out;
 	}
+
+	/*
+	 * Leave a trace in current->flags indicating we are already in
+	 * process of performing CPU hotplug.
+	 */
+	current->flags |= PF_HOTPLUG_CPU;
 	ret = notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu);
 	if (ret == NOTIFY_BAD) {
 		printk("%s: attempt to bring up CPU %u failed\n",
@@ -185,6 +217,7 @@ out_notify:
 	if (ret != 0)
 		notifier_call_chain(&cpu_chain, CPU_UP_CANCELED, hcpu);
 out:
+	current->flags &= ~PF_HOTPLUG_CPU;
 	up(&cpucontrol);
 	return ret;
 }
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 18d7d693fbba..6ee2cad530e8 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -167,7 +167,7 @@ static int enter_state(suspend_state_t state)
 {
 	int error;
 
-	if (pm_ops->valid && !pm_ops->valid(state))
+	if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
 		return -ENODEV;
 	if (down_trylock(&pm_sem))
 		return -EBUSY;
diff --git a/kernel/power/power.h b/kernel/power/power.h
index d4fd96a135ab..6c042b5ee14b 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -65,8 +65,8 @@ extern suspend_pagedir_t *pagedir_save;
 extern asmlinkage int swsusp_arch_suspend(void);
 extern asmlinkage int swsusp_arch_resume(void);
 
-extern int restore_highmem(void);
-extern struct pbe * alloc_pagedir(unsigned nr_pages);
+extern void free_pagedir(struct pbe *pblist);
+extern struct pbe *alloc_pagedir(unsigned nr_pages, gfp_t gfp_mask, int safe_needed);
 extern void create_pbe_list(struct pbe *pblist, unsigned nr_pages);
 extern void swsusp_free(void);
-extern int enough_swap(unsigned nr_pages);
+extern int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed);
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 723f5179883e..4a6dbcefd378 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -88,8 +88,7 @@ static int save_highmem_zone(struct zone *zone)
 	return 0;
 }
 
-
-static int save_highmem(void)
+int save_highmem(void)
 {
 	struct zone *zone;
 	int res = 0;
@@ -120,11 +119,7 @@ int restore_highmem(void)
 	}
 	return 0;
 }
-#else
-static int save_highmem(void) { return 0; }
-int restore_highmem(void) { return 0; }
-#endif /* CONFIG_HIGHMEM */
-
+#endif
 
 static int pfn_is_nosave(unsigned long pfn)
 {
@@ -216,7 +211,7 @@ static void copy_data_pages(struct pbe *pblist)
  *	free_pagedir - free pages allocated with alloc_pagedir()
  */
 
-static void free_pagedir(struct pbe *pblist)
+void free_pagedir(struct pbe *pblist)
 {
 	struct pbe *pbe;
 
@@ -269,9 +264,30 @@ void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
 	pr_debug("create_pbe_list(): initialized %d PBEs\n", num);
 }
 
-static void *alloc_image_page(void)
+/**
+ *	@safe_needed - on resume, for storing the PBE list and the image,
+ *	we can only use memory pages that do not conflict with the pages
+ *	which had been used before suspend.
+ *
+ *	The unsafe pages are marked with the PG_nosave_free flag
+ *
+ *	Allocated but unusable (ie eaten) memory pages should be marked
+ *	so that swsusp_free() can release them
+ */
+
+static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
 {
-	void *res = (void *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
+	void *res;
+
+	if (safe_needed)
+		do {
+			res = (void *)get_zeroed_page(gfp_mask);
+			if (res && PageNosaveFree(virt_to_page(res)))
+				/* This is for swsusp_free() */
+				SetPageNosave(virt_to_page(res));
+		} while (res && PageNosaveFree(virt_to_page(res)));
+	else
+		res = (void *)get_zeroed_page(gfp_mask);
 	if (res) {
 		SetPageNosave(virt_to_page(res));
 		SetPageNosaveFree(virt_to_page(res));
@@ -279,6 +295,11 @@ static void *alloc_image_page(void)
 	return res;
 }
 
+unsigned long get_safe_page(gfp_t gfp_mask)
+{
+	return (unsigned long)alloc_image_page(gfp_mask, 1);
+}
+
 /**
  *	alloc_pagedir - Allocate the page directory.
  *
@@ -292,7 +313,7 @@ static void *alloc_image_page(void)
  *	On each page we set up a list of struct_pbe elements.
  */
 
-struct pbe *alloc_pagedir(unsigned int nr_pages)
+struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed)
 {
 	unsigned int num;
 	struct pbe *pblist, *pbe;
@@ -301,12 +322,12 @@ struct pbe *alloc_pagedir(unsigned int nr_pages)
 		return NULL;
 
 	pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
-	pblist = alloc_image_page();
+	pblist = alloc_image_page(gfp_mask, safe_needed);
 	/* FIXME: rewrite this ugly loop */
 	for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
         		pbe = pbe->next, num += PBES_PER_PAGE) {
 		pbe += PB_PAGE_SKIP;
-		pbe->next = alloc_image_page();
+		pbe->next = alloc_image_page(gfp_mask, safe_needed);
 	}
 	if (!pbe) { /* get_zeroed_page() failed */
 		free_pagedir(pblist);
@@ -354,24 +375,32 @@ static int enough_free_mem(unsigned int nr_pages)
 		(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
 }
 
+int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
+{
+	struct pbe *p;
+
+	for_each_pbe (p, pblist) {
+		p->address = (unsigned long)alloc_image_page(gfp_mask, safe_needed);
+		if (!p->address)
+			return -ENOMEM;
+	}
+	return 0;
+}
 
 static struct pbe *swsusp_alloc(unsigned int nr_pages)
 {
-	struct pbe *pblist, *p;
+	struct pbe *pblist;
 
-	if (!(pblist = alloc_pagedir(nr_pages))) {
+	if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC | __GFP_COLD, 0))) {
 		printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
 		return NULL;
 	}
 	create_pbe_list(pblist, nr_pages);
 
-	for_each_pbe (p, pblist) {
-		p->address = (unsigned long)alloc_image_page();
-		if (!p->address) {
-			printk(KERN_ERR "suspend: Allocating image pages failed.\n");
-			swsusp_free();
-			return NULL;
-		}
+	if (alloc_data_pages(pblist, GFP_ATOMIC | __GFP_COLD, 0)) {
+		printk(KERN_ERR "suspend: Allocating image pages failed.\n");
+		swsusp_free();
+		return NULL;
 	}
 
 	return pblist;
@@ -382,11 +411,6 @@ asmlinkage int swsusp_save(void)
 	unsigned int nr_pages;
 
 	pr_debug("swsusp: critical section: \n");
-	if (save_highmem()) {
-		printk(KERN_CRIT "swsusp: Not enough free pages for highmem\n");
-		restore_highmem();
-		return -ENOMEM;
-	}
 
 	drain_local_pages();
 	nr_pages = count_data_pages();
@@ -406,11 +430,6 @@ asmlinkage int swsusp_save(void)
 		return -ENOMEM;
 	}
 
-	if (!enough_swap(nr_pages)) {
-		printk(KERN_ERR "swsusp: Not enough free swap\n");
-		return -ENOSPC;
-	}
-
 	pagedir_nosave = swsusp_alloc(nr_pages);
 	if (!pagedir_nosave)
 		return -ENOMEM;
diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index e1ab28b9b217..c05f46e7348f 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -73,6 +73,14 @@
 
 #include "power.h"
 
+#ifdef CONFIG_HIGHMEM
+int save_highmem(void);
+int restore_highmem(void);
+#else
+static int save_highmem(void) { return 0; }
+static int restore_highmem(void) { return 0; }
+#endif
+
 #define CIPHER "aes"
 #define MAXKEY 32
 #define MAXIV  32
@@ -500,6 +508,26 @@ static int write_pagedir(void)
 }
 
 /**
+ *	enough_swap - Make sure we have enough swap to save the image.
+ *
+ *	Returns TRUE or FALSE after checking the total amount of swap
+ *	space avaiable.
+ *
+ *	FIXME: si_swapinfo(&i) returns all swap devices information.
+ *	We should only consider resume_device.
+ */
+
+static int enough_swap(unsigned int nr_pages)
+{
+	struct sysinfo i;
+
+	si_swapinfo(&i);
+	pr_debug("swsusp: available swap: %lu pages\n", i.freeswap);
+	return i.freeswap > (nr_pages + PAGES_FOR_IO +
+		(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
+}
+
+/**
  *	write_suspend_image - Write entire image and metadata.
  *
  */
@@ -507,6 +535,11 @@ static int write_suspend_image(void)
 {
 	int error;
 
+	if (!enough_swap(nr_copy_pages)) {
+		printk(KERN_ERR "swsusp: Not enough free swap\n");
+		return -ENOSPC;
+	}
+
 	init_header();
 	if ((error = data_write()))
 		goto FreeData;
@@ -526,27 +559,6 @@ static int write_suspend_image(void)
 	goto Done;
 }
 
-/**
- *	enough_swap - Make sure we have enough swap to save the image.
- *
- *	Returns TRUE or FALSE after checking the total amount of swap
- *	space avaiable.
- *
- *	FIXME: si_swapinfo(&i) returns all swap devices information.
- *	We should only consider resume_device.
- */
-
-int enough_swap(unsigned int nr_pages)
-{
-	struct sysinfo i;
-
-	si_swapinfo(&i);
-	pr_debug("swsusp: available swap: %lu pages\n", i.freeswap);
-	return i.freeswap > (nr_pages + PAGES_FOR_IO +
-		(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
-}
-
-
 /* It is important _NOT_ to umount filesystems at this point. We want
  * them synced (in case something goes wrong) but we DO not want to mark
  * filesystem clean: it is not. (And it does not matter, if we resume
@@ -556,12 +568,15 @@ int swsusp_write(void)
 {
 	int error;
 
+	if ((error = swsusp_swap_check())) {
+		printk(KERN_ERR "swsusp: cannot find swap device, try swapon -a.\n");
+		return error;
+	}
 	lock_swapdevices();
 	error = write_suspend_image();
 	/* This will unlock ignored swap devices since writing is finished */
 	lock_swapdevices();
 	return error;
-
 }
 
 
@@ -569,6 +584,7 @@ int swsusp_write(void)
 int swsusp_suspend(void)
 {
 	int error;
+
 	if ((error = arch_prepare_suspend()))
 		return error;
 	local_irq_disable();
@@ -580,15 +596,12 @@ int swsusp_suspend(void)
 	 */
 	if ((error = device_power_down(PMSG_FREEZE))) {
 		printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
-		local_irq_enable();
-		return error;
+		goto Enable_irqs;
 	}
 
-	if ((error = swsusp_swap_check())) {
-		printk(KERN_ERR "swsusp: cannot find swap device, try swapon -a.\n");
-		device_power_up();
-		local_irq_enable();
-		return error;
+	if ((error = save_highmem())) {
+		printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");
+		goto Restore_highmem;
 	}
 
 	save_processor_state();
@@ -596,8 +609,10 @@ int swsusp_suspend(void)
 		printk(KERN_ERR "Error %d suspending\n", error);
 	/* Restore control flow magically appears here */
 	restore_processor_state();
+Restore_highmem:
 	restore_highmem();
 	device_power_up();
+Enable_irqs:
 	local_irq_enable();
 	return error;
 }
@@ -629,127 +644,43 @@ int swsusp_resume(void)
 }
 
 /**
- *	On resume, for storing the PBE list and the image,
- *	we can only use memory pages that do not conflict with the pages
- *	which had been used before suspend.
- *
- *	We don't know which pages are usable until we allocate them.
- *
- *	Allocated but unusable (ie eaten) memory pages are marked so that
- *	swsusp_free() can release them
- */
-
-unsigned long get_safe_page(gfp_t gfp_mask)
-{
-	unsigned long m;
-
-	do {
-		m = get_zeroed_page(gfp_mask);
-		if (m && PageNosaveFree(virt_to_page(m)))
-			/* This is for swsusp_free() */
-			SetPageNosave(virt_to_page(m));
-	} while (m && PageNosaveFree(virt_to_page(m)));
-	if (m) {
-		/* This is for swsusp_free() */
-		SetPageNosave(virt_to_page(m));
-		SetPageNosaveFree(virt_to_page(m));
-	}
-	return m;
-}
-
-/**
- *	check_pagedir - We ensure here that pages that the PBEs point to
- *	won't collide with pages where we're going to restore from the loaded
- *	pages later
- */
-
-static int check_pagedir(struct pbe *pblist)
-{
-	struct pbe *p;
-
-	/* This is necessary, so that we can free allocated pages
-	 * in case of failure
-	 */
-	for_each_pbe (p, pblist)
-		p->address = 0UL;
-
-	for_each_pbe (p, pblist) {
-		p->address = get_safe_page(GFP_ATOMIC);
-		if (!p->address)
-			return -ENOMEM;
-	}
-	return 0;
-}
-
-/**
- *	swsusp_pagedir_relocate - It is possible, that some memory pages
- *	occupied by the list of PBEs collide with pages where we're going to
- *	restore from the loaded pages later.  We relocate them here.
+ *	mark_unsafe_pages - mark the pages that cannot be used for storing
+ *	the image during resume, because they conflict with the pages that
+ *	had been used before suspend
  */
 
-static struct pbe *swsusp_pagedir_relocate(struct pbe *pblist)
+static void mark_unsafe_pages(struct pbe *pblist)
 {
 	struct zone *zone;
 	unsigned long zone_pfn;
-	struct pbe *pbpage, *tail, *p;
-	void *m;
-	int rel = 0;
+	struct pbe *p;
 
 	if (!pblist) /* a sanity check */
-		return NULL;
-
-	pr_debug("swsusp: Relocating pagedir (%lu pages to check)\n",
-			swsusp_info.pagedir_pages);
+		return;
 
 	/* Clear page flags */
-
 	for_each_zone (zone) {
-        	for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
-        		if (pfn_valid(zone_pfn + zone->zone_start_pfn))
-                		ClearPageNosaveFree(pfn_to_page(zone_pfn +
+		for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
+			if (pfn_valid(zone_pfn + zone->zone_start_pfn))
+				ClearPageNosaveFree(pfn_to_page(zone_pfn +
 					zone->zone_start_pfn));
 	}
 
 	/* Mark orig addresses */
-
 	for_each_pbe (p, pblist)
 		SetPageNosaveFree(virt_to_page(p->orig_address));
 
-	tail = pblist + PB_PAGE_SKIP;
-
-	/* Relocate colliding pages */
-
-	for_each_pb_page (pbpage, pblist) {
-		if (PageNosaveFree(virt_to_page((unsigned long)pbpage))) {
-			m = (void *)get_safe_page(GFP_ATOMIC | __GFP_COLD);
-			if (!m)
-				return NULL;
-			memcpy(m, (void *)pbpage, PAGE_SIZE);
-			if (pbpage == pblist)
-				pblist = (struct pbe *)m;
-			else
-				tail->next = (struct pbe *)m;
-			pbpage = (struct pbe *)m;
-
-			/* We have to link the PBEs again */
-			for (p = pbpage; p < pbpage + PB_PAGE_SKIP; p++)
-				if (p->next) /* needed to save the end */
-					p->next = p + 1;
-
-			rel++;
-		}
-		tail = pbpage + PB_PAGE_SKIP;
-	}
+}
 
-	/* This is for swsusp_free() */
-	for_each_pb_page (pbpage, pblist) {
-		SetPageNosave(virt_to_page(pbpage));
-		SetPageNosaveFree(virt_to_page(pbpage));
+static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
+{
+	/* We assume both lists contain the same number of elements */
+	while (src) {
+		dst->orig_address = src->orig_address;
+		dst->swap_address = src->swap_address;
+		dst = dst->next;
+		src = src->next;
 	}
-
-	printk("swsusp: Relocated %d pages\n", rel);
-
-	return pblist;
 }
 
 /*
@@ -888,7 +819,7 @@ static int check_sig(void)
 		 * Reset swap signature now.
 		 */
 		error = bio_write_page(0, &swsusp_header);
-	} else { 
+	} else {
 		return -EINVAL;
 	}
 	if (!error)
@@ -990,20 +921,25 @@ static int read_suspend_image(void)
 	int error = 0;
 	struct pbe *p;
 
-	if (!(p = alloc_pagedir(nr_copy_pages)))
+	if (!(p = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 0)))
 		return -ENOMEM;
 
 	if ((error = read_pagedir(p)))
 		return error;
-
 	create_pbe_list(p, nr_copy_pages);
-
-	if (!(pagedir_nosave = swsusp_pagedir_relocate(p)))
+	mark_unsafe_pages(p);
+	pagedir_nosave = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1);
+	if (pagedir_nosave) {
+		create_pbe_list(pagedir_nosave, nr_copy_pages);
+		copy_page_backup_list(pagedir_nosave, p);
+	}
+	free_pagedir(p);
+	if (!pagedir_nosave)
 		return -ENOMEM;
 
 	/* Allocate memory for the image and read the data from swap */
 
-	error = check_pagedir(pagedir_nosave);
+	error = alloc_data_pages(pagedir_nosave, GFP_ATOMIC, 1);
 
 	if (!error)
 		error = data_read(pagedir_nosave);
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 5b8dd98a230e..b88d4186cd7a 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -155,7 +155,7 @@ int ptrace_attach(struct task_struct *task)
 	retval = -EPERM;
 	if (task->pid <= 1)
 		goto bad;
-	if (task == current)
+	if (task->tgid == current->tgid)
 		goto bad;
 	/* the same process cannot be attached many times */
 	if (task->ptrace & PT_PTRACED)
diff --git a/kernel/sched.c b/kernel/sched.c
index 3ce26954be12..b6506671b2be 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -206,6 +206,7 @@ struct runqueue {
 	 */
 	unsigned long nr_running;
 #ifdef CONFIG_SMP
+	unsigned long prio_bias;
 	unsigned long cpu_load[3];
 #endif
 	unsigned long long nr_switches;
@@ -659,13 +660,68 @@ static int effective_prio(task_t *p)
 	return prio;
 }
 
+#ifdef CONFIG_SMP
+static inline void inc_prio_bias(runqueue_t *rq, int prio)
+{
+	rq->prio_bias += MAX_PRIO - prio;
+}
+
+static inline void dec_prio_bias(runqueue_t *rq, int prio)
+{
+	rq->prio_bias -= MAX_PRIO - prio;
+}
+
+static inline void inc_nr_running(task_t *p, runqueue_t *rq)
+{
+	rq->nr_running++;
+	if (rt_task(p)) {
+		if (p != rq->migration_thread)
+			/*
+			 * The migration thread does the actual balancing. Do
+			 * not bias by its priority as the ultra high priority
+			 * will skew balancing adversely.
+			 */
+			inc_prio_bias(rq, p->prio);
+	} else
+		inc_prio_bias(rq, p->static_prio);
+}
+
+static inline void dec_nr_running(task_t *p, runqueue_t *rq)
+{
+	rq->nr_running--;
+	if (rt_task(p)) {
+		if (p != rq->migration_thread)
+			dec_prio_bias(rq, p->prio);
+	} else
+		dec_prio_bias(rq, p->static_prio);
+}
+#else
+static inline void inc_prio_bias(runqueue_t *rq, int prio)
+{
+}
+
+static inline void dec_prio_bias(runqueue_t *rq, int prio)
+{
+}
+
+static inline void inc_nr_running(task_t *p, runqueue_t *rq)
+{
+	rq->nr_running++;
+}
+
+static inline void dec_nr_running(task_t *p, runqueue_t *rq)
+{
+	rq->nr_running--;
+}
+#endif
+
 /*
  * __activate_task - move a task to the runqueue.
  */
 static inline void __activate_task(task_t *p, runqueue_t *rq)
 {
 	enqueue_task(p, rq->active);
-	rq->nr_running++;
+	inc_nr_running(p, rq);
 }
 
 /*
@@ -674,7 +730,7 @@ static inline void __activate_task(task_t *p, runqueue_t *rq)
 static inline void __activate_idle_task(task_t *p, runqueue_t *rq)
 {
 	enqueue_task_head(p, rq->active);
-	rq->nr_running++;
+	inc_nr_running(p, rq);
 }
 
 static int recalc_task_prio(task_t *p, unsigned long long now)
@@ -759,7 +815,8 @@ static void activate_task(task_t *p, runqueue_t *rq, int local)
 	}
 #endif
 
-	p->prio = recalc_task_prio(p, now);
+	if (!rt_task(p))
+		p->prio = recalc_task_prio(p, now);
 
 	/*
 	 * This checks to make sure it's not an uninterruptible task
@@ -793,7 +850,7 @@ static void activate_task(task_t *p, runqueue_t *rq, int local)
  */
 static void deactivate_task(struct task_struct *p, runqueue_t *rq)
 {
-	rq->nr_running--;
+	dec_nr_running(p, rq);
 	dequeue_task(p, p->array);
 	p->array = NULL;
 }
@@ -808,21 +865,28 @@ static void deactivate_task(struct task_struct *p, runqueue_t *rq)
 #ifdef CONFIG_SMP
 static void resched_task(task_t *p)
 {
-	int need_resched, nrpolling;
+	int cpu;
 
 	assert_spin_locked(&task_rq(p)->lock);
 
-	/* minimise the chance of sending an interrupt to poll_idle() */
-	nrpolling = test_tsk_thread_flag(p,TIF_POLLING_NRFLAG);
-	need_resched = test_and_set_tsk_thread_flag(p,TIF_NEED_RESCHED);
-	nrpolling |= test_tsk_thread_flag(p,TIF_POLLING_NRFLAG);
+	if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
+		return;
+
+	set_tsk_thread_flag(p, TIF_NEED_RESCHED);
+
+	cpu = task_cpu(p);
+	if (cpu == smp_processor_id())
+		return;
 
-	if (!need_resched && !nrpolling && (task_cpu(p) != smp_processor_id()))
-		smp_send_reschedule(task_cpu(p));
+	/* NEED_RESCHED must be visible before we test POLLING_NRFLAG */
+	smp_mb();
+	if (!test_tsk_thread_flag(p, TIF_POLLING_NRFLAG))
+		smp_send_reschedule(cpu);
 }
 #else
 static inline void resched_task(task_t *p)
 {
+	assert_spin_locked(&task_rq(p)->lock);
 	set_tsk_need_resched(p);
 }
 #endif
@@ -930,27 +994,61 @@ void kick_process(task_t *p)
  * We want to under-estimate the load of migration sources, to
  * balance conservatively.
  */
-static inline unsigned long source_load(int cpu, int type)
+static inline unsigned long __source_load(int cpu, int type, enum idle_type idle)
 {
 	runqueue_t *rq = cpu_rq(cpu);
-	unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE;
+	unsigned long running = rq->nr_running;
+	unsigned long source_load, cpu_load = rq->cpu_load[type-1],
+		load_now = running * SCHED_LOAD_SCALE;
+
 	if (type == 0)
-		return load_now;
+		source_load = load_now;
+	else
+		source_load = min(cpu_load, load_now);
 
-	return min(rq->cpu_load[type-1], load_now);
+	if (running > 1 || (idle == NOT_IDLE && running))
+		/*
+		 * If we are busy rebalancing the load is biased by
+		 * priority to create 'nice' support across cpus. When
+		 * idle rebalancing we should only bias the source_load if
+		 * there is more than one task running on that queue to
+		 * prevent idle rebalance from trying to pull tasks from a
+		 * queue with only one running task.
+		 */
+		source_load = source_load * rq->prio_bias / running;
+
+	return source_load;
+}
+
+static inline unsigned long source_load(int cpu, int type)
+{
+	return __source_load(cpu, type, NOT_IDLE);
 }
 
 /*
  * Return a high guess at the load of a migration-target cpu
  */
-static inline unsigned long target_load(int cpu, int type)
+static inline unsigned long __target_load(int cpu, int type, enum idle_type idle)
 {
 	runqueue_t *rq = cpu_rq(cpu);
-	unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE;
+	unsigned long running = rq->nr_running;
+	unsigned long target_load, cpu_load = rq->cpu_load[type-1],
+		load_now = running * SCHED_LOAD_SCALE;
+
 	if (type == 0)
-		return load_now;
+		target_load = load_now;
+	else
+		target_load = max(cpu_load, load_now);
+
+	if (running > 1 || (idle == NOT_IDLE && running))
+		target_load = target_load * rq->prio_bias / running;
 
-	return max(rq->cpu_load[type-1], load_now);
+	return target_load;
+}
+
+static inline unsigned long target_load(int cpu, int type)
+{
+	return __target_load(cpu, type, NOT_IDLE);
 }
 
 /*
@@ -1411,7 +1509,7 @@ void fastcall wake_up_new_task(task_t *p, unsigned long clone_flags)
 				list_add_tail(&p->run_list, &current->run_list);
 				p->array = current->array;
 				p->array->nr_active++;
-				rq->nr_running++;
+				inc_nr_running(p, rq);
 			}
 			set_need_resched();
 		} else
@@ -1756,9 +1854,9 @@ void pull_task(runqueue_t *src_rq, prio_array_t *src_array, task_t *p,
 	       runqueue_t *this_rq, prio_array_t *this_array, int this_cpu)
 {
 	dequeue_task(p, src_array);
-	src_rq->nr_running--;
+	dec_nr_running(p, src_rq);
 	set_task_cpu(p, this_cpu);
-	this_rq->nr_running++;
+	inc_nr_running(p, this_rq);
 	enqueue_task(p, this_array);
 	p->timestamp = (p->timestamp - src_rq->timestamp_last_tick)
 				+ this_rq->timestamp_last_tick;
@@ -1937,9 +2035,9 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
 
 			/* Bias balancing toward cpus of our domain */
 			if (local_group)
-				load = target_load(i, load_idx);
+				load = __target_load(i, load_idx, idle);
 			else
-				load = source_load(i, load_idx);
+				load = __source_load(i, load_idx, idle);
 
 			avg_load += load;
 		}
@@ -2044,14 +2142,15 @@ out_balanced:
 /*
  * find_busiest_queue - find the busiest runqueue among the cpus in group.
  */
-static runqueue_t *find_busiest_queue(struct sched_group *group)
+static runqueue_t *find_busiest_queue(struct sched_group *group,
+	enum idle_type idle)
 {
 	unsigned long load, max_load = 0;
 	runqueue_t *busiest = NULL;
 	int i;
 
 	for_each_cpu_mask(i, group->cpumask) {
-		load = source_load(i, 0);
+		load = __source_load(i, 0, idle);
 
 		if (load > max_load) {
 			max_load = load;
@@ -2095,7 +2194,7 @@ static int load_balance(int this_cpu, runqueue_t *this_rq,
 		goto out_balanced;
 	}
 
-	busiest = find_busiest_queue(group);
+	busiest = find_busiest_queue(group, idle);
 	if (!busiest) {
 		schedstat_inc(sd, lb_nobusyq[idle]);
 		goto out_balanced;
@@ -2218,7 +2317,7 @@ static int load_balance_newidle(int this_cpu, runqueue_t *this_rq,
 		goto out_balanced;
 	}
 
-	busiest = find_busiest_queue(group);
+	busiest = find_busiest_queue(group, NEWLY_IDLE);
 	if (!busiest) {
 		schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]);
 		goto out_balanced;
@@ -3451,8 +3550,10 @@ void set_user_nice(task_t *p, long nice)
 		goto out_unlock;
 	}
 	array = p->array;
-	if (array)
+	if (array) {
 		dequeue_task(p, array);
+		dec_prio_bias(rq, p->static_prio);
+	}
 
 	old_prio = p->prio;
 	new_prio = NICE_TO_PRIO(nice);
@@ -3462,6 +3563,7 @@ void set_user_nice(task_t *p, long nice)
 
 	if (array) {
 		enqueue_task(p, array);
+		inc_prio_bias(rq, p->static_prio);
 		/*
 		 * If the task increased its priority or is running and
 		 * lowered its priority, then reschedule its CPU:
diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index a2dcceb9437d..c67189a25d52 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -73,9 +73,6 @@ void softlockup_tick(struct pt_regs *regs)
 static int watchdog(void * __bind_cpu)
 {
 	struct sched_param param = { .sched_priority = 99 };
-	int this_cpu = (long) __bind_cpu;
-
-	printk("softlockup thread %d started up.\n", this_cpu);
 
 	sched_setscheduler(current, SCHED_FIFO, &param);
 	current->flags |= PF_NOFREEZE;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c4f35f96884d..9990e10192e8 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -169,7 +169,7 @@ struct file_operations proc_sys_file_operations = {
 
 extern struct proc_dir_entry *proc_sys_root;
 
-static void register_proc_table(ctl_table *, struct proc_dir_entry *);
+static void register_proc_table(ctl_table *, struct proc_dir_entry *, void *);
 static void unregister_proc_table(ctl_table *, struct proc_dir_entry *);
 #endif
 
@@ -992,10 +992,51 @@ static ctl_table dev_table[] = {
 
 extern void init_irq_proc (void);
 
+static DEFINE_SPINLOCK(sysctl_lock);
+
+/* called under sysctl_lock */
+static int use_table(struct ctl_table_header *p)
+{
+	if (unlikely(p->unregistering))
+		return 0;
+	p->used++;
+	return 1;
+}
+
+/* called under sysctl_lock */
+static void unuse_table(struct ctl_table_header *p)
+{
+	if (!--p->used)
+		if (unlikely(p->unregistering))
+			complete(p->unregistering);
+}
+
+/* called under sysctl_lock, will reacquire if has to wait */
+static void start_unregistering(struct ctl_table_header *p)
+{
+	/*
+	 * if p->used is 0, nobody will ever touch that entry again;
+	 * we'll eliminate all paths to it before dropping sysctl_lock
+	 */
+	if (unlikely(p->used)) {
+		struct completion wait;
+		init_completion(&wait);
+		p->unregistering = &wait;
+		spin_unlock(&sysctl_lock);
+		wait_for_completion(&wait);
+		spin_lock(&sysctl_lock);
+	}
+	/*
+	 * do not remove from the list until nobody holds it; walking the
+	 * list in do_sysctl() relies on that.
+	 */
+	list_del_init(&p->ctl_entry);
+}
+
 void __init sysctl_init(void)
 {
 #ifdef CONFIG_PROC_FS
-	register_proc_table(root_table, proc_sys_root);
+	register_proc_table(root_table, proc_sys_root, &root_table_header);
 	init_irq_proc();
 #endif
 }
@@ -1004,6 +1045,7 @@ int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *ol
 	       void __user *newval, size_t newlen)
 {
 	struct list_head *tmp;
+	int error = -ENOTDIR;
 
 	if (nlen <= 0 || nlen >= CTL_MAXNAME)
 		return -ENOTDIR;
@@ -1012,20 +1054,30 @@ int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *ol
 		if (!oldlenp || get_user(old_len, oldlenp))
 			return -EFAULT;
 	}
+	spin_lock(&sysctl_lock);
 	tmp = &root_table_header.ctl_entry;
 	do {
 		struct ctl_table_header *head =
 			list_entry(tmp, struct ctl_table_header, ctl_entry);
 		void *context = NULL;
-		int error = parse_table(name, nlen, oldval, oldlenp, 
+
+		if (!use_table(head))
+			continue;
+
+		spin_unlock(&sysctl_lock);
+
+		error = parse_table(name, nlen, oldval, oldlenp, 
 					newval, newlen, head->ctl_table,
 					&context);
 		kfree(context);
+
+		spin_lock(&sysctl_lock);
+		unuse_table(head);
 		if (error != -ENOTDIR)
-			return error;
-		tmp = tmp->next;
-	} while (tmp != &root_table_header.ctl_entry);
-	return -ENOTDIR;
+			break;
+	} while ((tmp = tmp->next) != &root_table_header.ctl_entry);
+	spin_unlock(&sysctl_lock);
+	return error;
 }
 
 asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
@@ -1236,12 +1288,16 @@ struct ctl_table_header *register_sysctl_table(ctl_table * table,
 		return NULL;
 	tmp->ctl_table = table;
 	INIT_LIST_HEAD(&tmp->ctl_entry);
+	tmp->used = 0;
+	tmp->unregistering = NULL;
+	spin_lock(&sysctl_lock);
 	if (insert_at_head)
 		list_add(&tmp->ctl_entry, &root_table_header.ctl_entry);
 	else
 		list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
+	spin_unlock(&sysctl_lock);
 #ifdef CONFIG_PROC_FS
-	register_proc_table(table, proc_sys_root);
+	register_proc_table(table, proc_sys_root, tmp);
 #endif
 	return tmp;
 }
@@ -1255,10 +1311,13 @@ struct ctl_table_header *register_sysctl_table(ctl_table * table,
  */
 void unregister_sysctl_table(struct ctl_table_header * header)
 {
-	list_del(&header->ctl_entry);
+	might_sleep();
+	spin_lock(&sysctl_lock);
+	start_unregistering(header);
 #ifdef CONFIG_PROC_FS
 	unregister_proc_table(header->ctl_table, proc_sys_root);
 #endif
+	spin_unlock(&sysctl_lock);
 	kfree(header);
 }
 
@@ -1269,7 +1328,7 @@ void unregister_sysctl_table(struct ctl_table_header * header)
 #ifdef CONFIG_PROC_FS
 
 /* Scan the sysctl entries in table and add them all into /proc */
-static void register_proc_table(ctl_table * table, struct proc_dir_entry *root)
+static void register_proc_table(ctl_table * table, struct proc_dir_entry *root, void *set)
 {
 	struct proc_dir_entry *de;
 	int len;
@@ -1305,13 +1364,14 @@ static void register_proc_table(ctl_table * table, struct proc_dir_entry *root)
 			de = create_proc_entry(table->procname, mode, root);
 			if (!de)
 				continue;
+			de->set = set;
 			de->data = (void *) table;
 			if (table->proc_handler)
 				de->proc_fops = &proc_sys_file_operations;
 		}
 		table->de = de;
 		if (de->mode & S_IFDIR)
-			register_proc_table(table->child, de);
+			register_proc_table(table->child, de, set);
 	}
 }
 
@@ -1336,6 +1396,13 @@ static void unregister_proc_table(ctl_table * table, struct proc_dir_entry *root
 				continue;
 		}
 
+		/*
+		 * In any case, mark the entry as goner; we'll keep it
+		 * around if it's busy, but we'll know to do nothing with
+		 * its fields.  We are under sysctl_lock here.
+		 */
+		de->data = NULL;
+
 		/* Don't unregister proc entries that are still being used.. */
 		if (atomic_read(&de->count))
 			continue;
@@ -1349,27 +1416,38 @@ static ssize_t do_rw_proc(int write, struct file * file, char __user * buf,
 			  size_t count, loff_t *ppos)
 {
 	int op;
-	struct proc_dir_entry *de;
+	struct proc_dir_entry *de = PDE(file->f_dentry->d_inode);
 	struct ctl_table *table;
 	size_t res;
-	ssize_t error;
-	
-	de = PDE(file->f_dentry->d_inode);
-	if (!de || !de->data)
-		return -ENOTDIR;
-	table = (struct ctl_table *) de->data;
-	if (!table || !table->proc_handler)
-		return -ENOTDIR;
-	op = (write ? 002 : 004);
-	if (ctl_perm(table, op))
-		return -EPERM;
+	ssize_t error = -ENOTDIR;
 	
-	res = count;
-
-	error = (*table->proc_handler) (table, write, file, buf, &res, ppos);
-	if (error)
-		return error;
-	return res;
+	spin_lock(&sysctl_lock);
+	if (de && de->data && use_table(de->set)) {
+		/*
+		 * at that point we know that sysctl was not unregistered
+		 * and won't be until we finish
+		 */
+		spin_unlock(&sysctl_lock);
+		table = (struct ctl_table *) de->data;
+		if (!table || !table->proc_handler)
+			goto out;
+		error = -EPERM;
+		op = (write ? 002 : 004);
+		if (ctl_perm(table, op))
+			goto out;
+		
+		/* careful: calling conventions are nasty here */
+		res = count;
+		error = (*table->proc_handler)(table, write, file,
+						buf, &res, ppos);
+		if (!error)
+			error = res;
+	out:
+		spin_lock(&sysctl_lock);
+		unuse_table(de->set);
+	}
+	spin_unlock(&sysctl_lock);
+	return error;
 }
 
 static int proc_opensys(struct inode *inode, struct file *file)