[PATCH 19/36] autonuma: memory follows CPU algorithm and task/mm_autonuma stats collection

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This implements the following parts of autonuma:

o knuma_scand: daemon for setting pte_numa and pmd_numa while
  gathering NUMA mm stats

o NUMA hinting page fault handler: queues pages for migration and
  gathers NUMA task stats

o knuma_migrated: kernel threads that migrate memory from remote nodes
  to the local node

o The rest of autonuma core logic: false sharing detection, sysfs and
  initialization routines

The AutoNUMA algorithm when knuma_scand is not running is fully
bypassed and it will not alter the runtime of memory management or the
scheduler.

The whole AutoNUMA logic is a chain reaction as a result of the
actions of the knuma_scand. Various parts of the code can be described
like different gears (gears as in glxgears).

knuma_scand is the first gear and it collects the mm_autonuma
per-process statistics and at the same time it sets the ptes and pmds
it scans respectively as pte_numa and pmd_numa.

The second gear are the numa hinting page faults. These are triggered
by the pte_numa/pmd_numa pmd/ptes. They collect the task_autonuma
per-thread statistics. They also implement the memory follow CPU logic
where we track if pages are repeatedly accessed by remote nodes. The
memory follow CPU logic can decide to migrate pages across different
NUMA nodes by queuing the pages for migration in the per-node
knuma_migrated queues.

The third gear is knuma_migrated. There is one knuma_migrated daemon
per node. Pages pending for migration are queued in a matrix of
lists. Each knuma_migrated (in parallel with each other) goes over
those lists and migrates the pages queued for migration in round robin
from each incoming node to the node where knuma_migrated is running.

The fourth gear is the NUMA scheduler balancing code. That computes
the statistical information collected in mm->mm_autonuma and
p->task_autonuma and evaluates the status of all CPUs to decide if
tasks should be migrated to CPUs in remote nodes.

The only "input" information of the AutoNUMA algorithm that isn't
collected through NUMA hinting page faults are the per-process
mm->mm_autonuma statistics. Those mm_autonuma statistics are collected
by the knuma_scand pmd/pte scans that are also responsible for setting
pte_numa/pmd_numa to activate the NUMA hinting page faults.

knuma_scand -> NUMA hinting page faults
  |                       |
 \|/                     \|/
mm_autonuma  <->  task_autonuma (CPU follow memory, this is mm_autonuma too)
                  page last_nid  (false thread sharing/thread shared memory detection )
                  queue or cancel page migration (memory follow CPU)

There is one knuma_migratedN daemon per NUMA node. After pages are
queued for a node, the knuma_migratedN daemon for that node will take
care of migrating pages to the node at a steady rate and in parallel
with the deamons for other nodes. Each daemon migrates pages in a
round-robin fashion, from all the other nodes. This keeps all memory
channels in a large system active at the same time and will avoid
hitting on a single memory channel for too long, thus minimizing
memory bus migration latency effects.

Once a page is queued for asynchronous migration, the migration can
still be canceled if false sharing is later detected.

The code includes some fixes from Hillf Danton <dhillf@xxxxxxxxx>.

Math documentation on autonuma_last_nid in the header of
last_nid_set() reworked from sched-numa code by Peter Zijlstra
<a.p.zijlstra@xxxxxxxxx>.

Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Signed-off-by: Hillf Danton <dhillf@xxxxxxxxx>
---
 mm/autonuma.c | 1619 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 1619 insertions(+), 0 deletions(-)
 create mode 100644 mm/autonuma.c

diff --git a/mm/autonuma.c b/mm/autonuma.c
new file mode 100644
index 0000000..a505ec3
--- /dev/null
+++ b/mm/autonuma.c
@@ -0,0 +1,1619 @@
+/*
+ *  Copyright (C) 2012  Red Hat, Inc.
+ *
+ *  This work is licensed under the terms of the GNU GPL, version 2. See
+ *  the COPYING file in the top-level directory.
+ *
+ *  Boot with "numa=fake=2" to test on non NUMA systems.
+ */
+
+#include <linux/mm.h>
+#include <linux/rmap.h>
+#include <linux/kthread.h>
+#include <linux/mmu_notifier.h>
+#include <linux/freezer.h>
+#include <linux/mm_inline.h>
+#include <linux/migrate.h>
+#include <linux/swap.h>
+#include <linux/autonuma.h>
+#include <asm/tlbflush.h>
+#include <asm/pgtable.h>
+
+unsigned long autonuma_flags __read_mostly =
+	(1<<AUTONUMA_POSSIBLE_FLAG)
+	|(1<<AUTONUMA_SCHED_RESET_FLAG)
+#ifdef CONFIG_AUTONUMA_DEFAULT_ENABLED
+	|(1<<AUTONUMA_ENABLED_FLAG)
+#endif
+	|(1<<AUTONUMA_SCAN_PMD_FLAG);
+
+static DEFINE_MUTEX(knumad_mm_mutex);
+
+/* knuma_scand */
+static unsigned int scan_sleep_millisecs __read_mostly = 100;
+static unsigned int scan_sleep_pass_millisecs __read_mostly = 10000;
+static unsigned int pages_to_scan __read_mostly = 128*1024*1024/PAGE_SIZE;
+static DECLARE_WAIT_QUEUE_HEAD(knuma_scand_wait);
+static unsigned long full_scans;
+static unsigned long pages_scanned;
+
+/* knuma_migrated */
+static unsigned int migrate_sleep_millisecs __read_mostly = 100;
+static unsigned int pages_to_migrate __read_mostly = 128*1024*1024/PAGE_SIZE;
+static volatile unsigned long pages_migrated;
+
+static struct knuma_scand_data {
+	struct list_head mm_head; /* entry: mm->mm_autonuma->mm_node */
+	struct mm_struct *mm;
+	unsigned long address;
+	unsigned long *mm_numa_fault_tmp;
+} knuma_scand_data = {
+	.mm_head = LIST_HEAD_INIT(knuma_scand_data.mm_head),
+};
+
+static inline void autonuma_migrate_lock(int nid)
+{
+	spin_lock(&NODE_DATA(nid)->autonuma_lock);
+}
+
+static inline void autonuma_migrate_unlock(int nid)
+{
+	spin_unlock(&NODE_DATA(nid)->autonuma_lock);
+}
+
+static inline void autonuma_migrate_lock_irq(int nid)
+{
+	spin_lock_irq(&NODE_DATA(nid)->autonuma_lock);
+}
+
+static inline void autonuma_migrate_unlock_irq(int nid)
+{
+	spin_unlock_irq(&NODE_DATA(nid)->autonuma_lock);
+}
+
+/* caller already holds the compound_lock */
+void autonuma_migrate_split_huge_page(struct page *page,
+				      struct page *page_tail)
+{
+	int nid, last_nid;
+
+	nid = page->autonuma_migrate_nid;
+	VM_BUG_ON(nid >= MAX_NUMNODES);
+	VM_BUG_ON(nid < -1);
+	VM_BUG_ON(page_tail->autonuma_migrate_nid != -1);
+	if (nid >= 0) {
+		VM_BUG_ON(page_to_nid(page) != page_to_nid(page_tail));
+
+		/*
+		 * The caller only takes the compound_lock for the
+		 * head page. Here we take the lock on the tail page,
+		 * too. So after the pages become visible (after the
+		 * below autonuma_migrate_unlock), they can't be
+		 * removed form the LRU until we drop the
+		 * compound_lock for page_tail.
+		 */
+		compound_lock(page_tail);
+		autonuma_migrate_lock(nid);
+		list_add_tail(&page_tail->autonuma_migrate_node,
+			      &page->autonuma_migrate_node);
+		autonuma_migrate_unlock(nid);
+
+		page_tail->autonuma_migrate_nid = nid;
+		compound_unlock(page_tail);
+	}
+
+	last_nid = ACCESS_ONCE(page->autonuma_last_nid);
+	if (last_nid >= 0)
+		page_tail->autonuma_last_nid = last_nid;
+}
+
+void __autonuma_migrate_page_remove(struct page *page)
+{
+	unsigned long flags;
+	int nid;
+
+	flags = compound_lock_irqsave(page);
+
+	nid = page->autonuma_migrate_nid;
+	VM_BUG_ON(nid >= MAX_NUMNODES);
+	VM_BUG_ON(nid < -1);
+	if (nid >= 0) {
+		int numpages = hpage_nr_pages(page);
+		autonuma_migrate_lock(nid);
+		list_del(&page->autonuma_migrate_node);
+		NODE_DATA(nid)->autonuma_nr_migrate_pages -= numpages;
+		autonuma_migrate_unlock(nid);
+
+		page->autonuma_migrate_nid = -1;
+	}
+
+	compound_unlock_irqrestore(page, flags);
+}
+
+static void __autonuma_migrate_page_add(struct page *page, int dst_nid,
+					int page_nid)
+{
+	unsigned long flags;
+	int nid;
+	int numpages;
+	unsigned long nr_migrate_pages;
+	wait_queue_head_t *wait_queue;
+
+	VM_BUG_ON(dst_nid >= MAX_NUMNODES);
+	VM_BUG_ON(dst_nid < -1);
+	VM_BUG_ON(page_nid >= MAX_NUMNODES);
+	VM_BUG_ON(page_nid < -1);
+
+	VM_BUG_ON(page_nid == dst_nid);
+	VM_BUG_ON(page_to_nid(page) != page_nid);
+
+	/*
+	 * Remove the page from the old migrate node's lru list (if it
+	 * was queued) and add it to the new node's lru list. The page
+	 * autonuma_migrate_nid that tracks where and if the page is
+	 * queued is protected by the compound lock so take that
+	 * first.
+	*/
+	flags = compound_lock_irqsave(page);
+
+	numpages = hpage_nr_pages(page);
+	nid = page->autonuma_migrate_nid;
+	VM_BUG_ON(nid >= MAX_NUMNODES);
+	VM_BUG_ON(nid < -1);
+	if (nid >= 0) {
+		autonuma_migrate_lock(nid);
+		list_del(&page->autonuma_migrate_node);
+		NODE_DATA(nid)->autonuma_nr_migrate_pages -= numpages;
+		autonuma_migrate_unlock(nid);
+	}
+
+	autonuma_migrate_lock(dst_nid);
+	list_add(&page->autonuma_migrate_node,
+		 &NODE_DATA(dst_nid)->autonuma_migrate_head[page_nid]);
+	NODE_DATA(dst_nid)->autonuma_nr_migrate_pages += numpages;
+	nr_migrate_pages = NODE_DATA(dst_nid)->autonuma_nr_migrate_pages;
+
+	autonuma_migrate_unlock(dst_nid);
+
+	page->autonuma_migrate_nid = dst_nid;
+
+	compound_unlock_irqrestore(page, flags);
+
+	if (!autonuma_migrate_defer()) {
+		wait_queue = &NODE_DATA(dst_nid)->autonuma_knuma_migrated_wait;
+		if (nr_migrate_pages >= pages_to_migrate &&
+		    nr_migrate_pages - numpages < pages_to_migrate &&
+		    waitqueue_active(wait_queue))
+			wake_up_interruptible(wait_queue);
+	}
+}
+
+static void autonuma_migrate_page_add(struct page *page, int dst_nid,
+				      int page_nid)
+{
+	int migrate_nid = ACCESS_ONCE(page->autonuma_migrate_nid);
+	if (migrate_nid != dst_nid)
+		__autonuma_migrate_page_add(page, dst_nid, page_nid);
+}
+
+static bool autonuma_balance_pgdat(struct pglist_data *pgdat,
+				   int nr_migrate_pages)
+{
+	/* FIXME: this only check the wmarks, make it move
+	 * "unused" memory or pagecache by queuing it to
+	 * pgdat->autonuma_migrate_head[pgdat->node_id].
+	 */
+	int z;
+	for (z = pgdat->nr_zones - 1; z >= 0; z--) {
+		struct zone *zone = pgdat->node_zones + z;
+
+		if (!populated_zone(zone))
+			continue;
+
+		if (zone->all_unreclaimable)
+			continue;
+
+		/*
+		 * FIXME: in theory we're ok if we can obtain
+		 * pages_to_migrate pages from all zones, it doesn't
+		 * need to be all in a single zone. We care about the
+		 * pgdat, not the zone.
+		 */
+
+		/*
+		 * Try not to wakeup kswapd by allocating
+		 * pages_to_migrate pages.
+		 */
+		if (!zone_watermark_ok(zone, 0,
+				       high_wmark_pages(zone) +
+				       nr_migrate_pages,
+				       0, 0))
+			continue;
+		return true;
+	}
+	return false;
+}
+
+static void cpu_follow_memory_pass(struct task_struct *p,
+				   struct task_autonuma *task_autonuma,
+				   unsigned long *task_numa_fault)
+{
+	int nid;
+	/* If a new pass started, degrade the stats by a factor of 2 */
+	for_each_node(nid)
+		task_numa_fault[nid] >>= 1;
+	task_autonuma->task_numa_fault_tot >>= 1;
+}
+
+static void numa_hinting_fault_cpu_follow_memory(struct task_struct *p,
+						 int access_nid,
+						 int numpages,
+						 bool new_pass)
+{
+	struct task_autonuma *task_autonuma = p->task_autonuma;
+	unsigned long *task_numa_fault = task_autonuma->task_numa_fault;
+
+	/* prevent sched_autonuma_balance() to run on top of us */
+	local_bh_disable();
+
+	if (unlikely(new_pass))
+		cpu_follow_memory_pass(p, task_autonuma, task_numa_fault);
+	task_numa_fault[access_nid] += numpages;
+	task_autonuma->task_numa_fault_tot += numpages;
+
+	local_bh_enable();
+}
+
+/*
+ * In this function we build a temporal CPU_node<->page relation by
+ * using a two-stage autonuma_last_nid filter to remove short/unlikely
+ * relations.
+ *
+ * Using P(p) ~ n_p / n_t as per frequentest probability, we can
+ * equate a node's CPU usage of a particular page (n_p) per total
+ * usage of this page (n_t) (in a given time-span) to a probability.
+ *
+ * Our periodic faults will then sample this probability and getting
+ * the same result twice in a row, given these samples are fully
+ * independent, is then given by P(n)^2, provided our sample period
+ * is sufficiently short compared to the usage pattern.
+ *
+ * This quadric squishes small probabilities, making it less likely
+ * we act on an unlikely CPU_node<->page relation.
+ */
+static inline bool last_nid_set(struct page *page, int this_nid)
+{
+	bool ret = true;
+	int autonuma_last_nid = ACCESS_ONCE(page->autonuma_last_nid);
+	VM_BUG_ON(this_nid < 0);
+	VM_BUG_ON(this_nid >= MAX_NUMNODES);
+	if (autonuma_last_nid >= 0 && autonuma_last_nid != this_nid) {
+		int migrate_nid = ACCESS_ONCE(page->autonuma_migrate_nid);
+		if (migrate_nid >= 0)
+			__autonuma_migrate_page_remove(page);
+		ret = false;
+	}
+	if (autonuma_last_nid != this_nid)
+		ACCESS_ONCE(page->autonuma_last_nid) = this_nid;
+	return ret;
+}
+
+static int __page_migrate_nid(struct page *page, int page_nid)
+{
+	int migrate_nid = ACCESS_ONCE(page->autonuma_migrate_nid);
+	if (migrate_nid < 0)
+		migrate_nid = page_nid;
+	return migrate_nid;
+}
+
+static int page_migrate_nid(struct page *page)
+{
+	return __page_migrate_nid(page, page_to_nid(page));
+}
+
+static int numa_hinting_fault_memory_follow_cpu(struct page *page,
+						int this_nid, int page_nid,
+						bool new_pass)
+{
+	if (!last_nid_set(page, this_nid))
+		return page_nid;
+	if (!PageLRU(page))
+		return page_nid;
+	if (this_nid != page_nid)
+		autonuma_migrate_page_add(page, this_nid, page_nid);
+	else
+		autonuma_migrate_page_remove(page);
+	return this_nid;
+}
+
+void numa_hinting_fault(struct page *page, int numpages)
+{
+	/*
+	 * "current->mm" could be different from the "mm" where the
+	 * NUMA hinting page fault happened, if get_user_pages()
+	 * triggered the fault on some other process "mm". That is ok,
+	 * all we care about is to count the "page_nid" access on the
+	 * current->task_autonuma, even if the page belongs to a
+	 * different "mm".
+	 */
+	WARN_ON_ONCE(!current->mm);
+	if (likely(current->mm && !current->mempolicy && autonuma_enabled())) {
+		struct task_struct *p = current;
+		int this_nid, page_nid, access_nid;
+		bool new_pass;
+
+		/*
+		 * new_pass is only true the first time the thread
+		 * faults on this pass of knuma_scand.
+		 */
+		new_pass = p->task_autonuma->task_numa_fault_pass !=
+			p->mm->mm_autonuma->mm_numa_fault_pass;
+		page_nid = page_to_nid(page);
+		this_nid = numa_node_id();
+		VM_BUG_ON(this_nid < 0);
+		VM_BUG_ON(this_nid >= MAX_NUMNODES);
+		access_nid = numa_hinting_fault_memory_follow_cpu(page,
+								  this_nid,
+								  page_nid,
+								  new_pass);
+		numa_hinting_fault_cpu_follow_memory(p, access_nid,
+						     numpages, new_pass);
+		if (unlikely(new_pass))
+			/*
+			 * Set the task's fault_pass equal to the new
+			 * mm's fault_pass, so new_pass will be false
+			 * on the next fault by this thread in this
+			 * same pass.
+			 */
+			p->task_autonuma->task_numa_fault_pass =
+				p->mm->mm_autonuma->mm_numa_fault_pass;
+	}
+}
+
+/* NUMA hinting page fault entry point for ptes */
+pte_t __pte_numa_fixup(struct mm_struct *mm, struct vm_area_struct *vma,
+		       unsigned long addr, pte_t pte, pte_t *ptep)
+{
+	struct page *page;
+	pte = pte_mknonnuma(pte);
+	set_pte_at(mm, addr, ptep, pte);
+	page = vm_normal_page(vma, addr, pte);
+	BUG_ON(!page);
+	numa_hinting_fault(page, 1);
+	return pte;
+}
+
+/* NUMA hinting page fault entry point for regular pmds */
+void __pmd_numa_fixup(struct mm_struct *mm,
+		      unsigned long addr, pmd_t *pmdp)
+{
+	pmd_t pmd;
+	pte_t *pte;
+	unsigned long _addr = addr & PMD_MASK;
+	unsigned long offset;
+	spinlock_t *ptl;
+	bool numa = false;
+	struct vm_area_struct *vma;
+
+	spin_lock(&mm->page_table_lock);
+	pmd = *pmdp;
+	if (pmd_numa(pmd)) {
+		set_pmd_at(mm, _addr, pmdp, pmd_mknonnuma(pmd));
+		numa = true;
+	}
+	spin_unlock(&mm->page_table_lock);
+
+	if (!numa)
+		return;
+
+	vma = find_vma(mm, _addr);
+	/* we're in a page fault so some vma must be in the range */
+	BUG_ON(!vma);
+	BUG_ON(vma->vm_start >= _addr + PMD_SIZE);
+	offset = max(_addr, vma->vm_start) & ~PMD_MASK;
+	VM_BUG_ON(offset >= PMD_SIZE);
+	pte = pte_offset_map_lock(mm, pmdp, _addr, &ptl);
+	pte += offset >> PAGE_SHIFT;
+	for (addr = _addr + offset; addr < _addr + PMD_SIZE; pte++, addr += PAGE_SIZE) {
+		pte_t pteval = *pte;
+		struct page * page;
+		if (!pte_present(pteval))
+			continue;
+		if (addr >= vma->vm_end) {
+			vma = find_vma(mm, addr);
+			/* there's a pte present so there must be a vma */
+			BUG_ON(!vma);
+			BUG_ON(addr < vma->vm_start);
+		}
+		if (pte_numa(pteval)) {
+			pteval = pte_mknonnuma(pteval);
+			set_pte_at(mm, addr, pte, pteval);
+		}
+		page = vm_normal_page(vma, addr, pteval);
+		if (unlikely(!page))
+			continue;
+		/* only check non-shared pages */
+		if (page_mapcount(page) != 1)
+			continue;
+		numa_hinting_fault(page, 1);
+	}
+	pte_unmap_unlock(pte, ptl);
+}
+
+static inline int task_autonuma_size(void)
+{
+	return sizeof(struct task_autonuma) +
+		nr_node_ids * sizeof(unsigned long);
+}
+
+static inline int task_autonuma_reset_size(void)
+{
+	struct task_autonuma *task_autonuma = NULL;
+	return task_autonuma_size() -
+		(int)((char *)(&task_autonuma->task_numa_fault_pass) -
+		      (char *)task_autonuma);
+}
+
+static void task_autonuma_reset(struct task_autonuma *task_autonuma)
+{
+	task_autonuma->task_selected_nid = -1;
+	memset(&task_autonuma->task_numa_fault_pass, 0,
+	       task_autonuma_reset_size());
+}
+
+static inline int mm_autonuma_fault_size(void)
+{
+	return nr_node_ids * sizeof(unsigned long);
+}
+
+static inline int mm_autonuma_size(void)
+{
+	return sizeof(struct mm_autonuma) + mm_autonuma_fault_size();
+}
+
+static inline int mm_autonuma_reset_size(void)
+{
+	struct mm_autonuma *mm_autonuma = NULL;
+	return mm_autonuma_size() -
+		(int)((char *)(&mm_autonuma->mm_numa_fault_pass) -
+		      (char *)mm_autonuma);
+}
+
+static void mm_autonuma_reset(struct mm_autonuma *mm_autonuma)
+{
+	memset(&mm_autonuma->mm_numa_fault_pass, 0, mm_autonuma_reset_size());
+}
+
+void autonuma_setup_new_exec(struct task_struct *p)
+{
+	if (p->task_autonuma)
+		task_autonuma_reset(p->task_autonuma);
+	if (p->mm && p->mm->mm_autonuma)
+		mm_autonuma_reset(p->mm->mm_autonuma);
+}
+
+static inline int knumad_test_exit(struct mm_struct *mm)
+{
+	return atomic_read(&mm->mm_users) == 0;
+}
+
+/*
+ * Here we search for not shared page mappings (mapcount == 1) and we
+ * set up the pmd/pte_numa on those mappings so the very next access
+ * will fire a NUMA hinting page fault. We also collect the
+ * mm_autonuma statistics for this process mm at the same time.
+ */
+static int knuma_scand_pmd(struct mm_struct *mm,
+			   struct vm_area_struct *vma,
+			   unsigned long address)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte, *_pte;
+	struct page *page;
+	unsigned long _address, end;
+	spinlock_t *ptl;
+	int ret = 0;
+
+	VM_BUG_ON(address & ~PAGE_MASK);
+
+	pgd = pgd_offset(mm, address);
+	if (!pgd_present(*pgd))
+		goto out;
+
+	pud = pud_offset(pgd, address);
+	if (!pud_present(*pud))
+		goto out;
+
+	pmd = pmd_offset(pud, address);
+	if (pmd_none(*pmd))
+		goto out;
+
+	if (pmd_trans_huge(*pmd)) {
+		spin_lock(&mm->page_table_lock);
+		if (pmd_trans_huge(*pmd)) {
+			VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+			if (unlikely(pmd_trans_splitting(*pmd))) {
+				spin_unlock(&mm->page_table_lock);
+				wait_split_huge_page(vma->anon_vma, pmd);
+			} else {
+				int page_nid;
+				unsigned long *fault_tmp;
+				ret = HPAGE_PMD_NR;
+
+				page = pmd_page(*pmd);
+
+				/* only check non-shared pages */
+				if (page_mapcount(page) != 1) {
+					spin_unlock(&mm->page_table_lock);
+					goto out;
+				}
+
+				page_nid = page_migrate_nid(page);
+				fault_tmp = knuma_scand_data.mm_numa_fault_tmp;
+				fault_tmp[page_nid] += ret;
+
+				if (pmd_numa(*pmd)) {
+					spin_unlock(&mm->page_table_lock);
+					goto out;
+				}
+
+				set_pmd_at(mm, address, pmd, pmd_mknuma(*pmd));
+				/* defer TLB flush to lower the overhead */
+				spin_unlock(&mm->page_table_lock);
+				goto out;
+			}
+		} else
+			spin_unlock(&mm->page_table_lock);
+	}
+
+	VM_BUG_ON(!pmd_present(*pmd));
+
+	end = min(vma->vm_end, (address + PMD_SIZE) & PMD_MASK);
+	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
+	for (_address = address, _pte = pte; _address < end;
+	     _pte++, _address += PAGE_SIZE) {
+		pte_t pteval = *_pte;
+		unsigned long *fault_tmp;
+		if (!pte_present(pteval))
+			continue;
+		page = vm_normal_page(vma, _address, pteval);
+		if (unlikely(!page))
+			continue;
+		/* only check non-shared pages */
+		if (page_mapcount(page) != 1)
+			continue;
+
+		fault_tmp = knuma_scand_data.mm_numa_fault_tmp;
+		fault_tmp[page_migrate_nid(page)]++;
+
+		if (pte_numa(pteval))
+			continue;
+
+		if (!autonuma_scan_pmd())
+			set_pte_at(mm, _address, _pte, pte_mknuma(pteval));
+
+		/* defer TLB flush to lower the overhead */
+		ret++;
+	}
+	pte_unmap_unlock(pte, ptl);
+
+	if (ret && !pmd_numa(*pmd) && autonuma_scan_pmd()) {
+		/*
+		 * Mark the page table pmd as numa if "autonuma scan
+		 * pmd" mode is enabled.
+		 */
+		spin_lock(&mm->page_table_lock);
+		set_pmd_at(mm, address, pmd, pmd_mknuma(*pmd));
+		spin_unlock(&mm->page_table_lock);
+		/* defer TLB flush to lower the overhead */
+	}
+
+out:
+	return ret;
+}
+
+static void mm_numa_fault_tmp_flush(struct mm_struct *mm)
+{
+	int nid;
+	struct mm_autonuma *mma = mm->mm_autonuma;
+	unsigned long tot;
+	unsigned long *fault_tmp = knuma_scand_data.mm_numa_fault_tmp;
+
+	/* FIXME: would be better protected with write_seqlock_bh() */
+	local_bh_disable();
+
+	tot = 0;
+	for_each_node(nid) {
+		unsigned long faults = fault_tmp[nid];
+		fault_tmp[nid] = 0;
+		mma->mm_numa_fault[nid] = faults;
+		tot += faults;
+	}
+	mma->mm_numa_fault_tot = tot;
+
+	local_bh_enable();
+}
+
+static void mm_numa_fault_tmp_reset(void)
+{
+	memset(knuma_scand_data.mm_numa_fault_tmp, 0,
+	       mm_autonuma_fault_size());
+}
+
+static inline void validate_mm_numa_fault_tmp(unsigned long address)
+{
+#ifdef CONFIG_DEBUG_VM
+	int nid;
+	if (address)
+		return;
+	for_each_node(nid)
+		BUG_ON(knuma_scand_data.mm_numa_fault_tmp[nid]);
+#endif
+}
+
+/*
+ * Scan the next part of the mm. Keep track of the progress made and
+ * return it.
+ */
+static int knumad_do_scan(void)
+{
+	struct mm_struct *mm;
+	struct mm_autonuma *mm_autonuma;
+	unsigned long address;
+	struct vm_area_struct *vma;
+	int progress = 0;
+
+	mm = knuma_scand_data.mm;
+	/*
+	 * knuma_scand_data.mm is NULL after the end of each
+	 * knuma_scand pass. So when it's NULL we've start from
+	 * scratch from the very first mm in the list.
+	 */
+	if (!mm) {
+		if (unlikely(list_empty(&knuma_scand_data.mm_head)))
+			return pages_to_scan;
+		mm_autonuma = list_entry(knuma_scand_data.mm_head.next,
+					 struct mm_autonuma, mm_node);
+		mm = mm_autonuma->mm;
+		knuma_scand_data.address = 0;
+		knuma_scand_data.mm = mm;
+		atomic_inc(&mm->mm_count);
+		mm_autonuma->mm_numa_fault_pass++;
+	}
+	address = knuma_scand_data.address;
+
+	validate_mm_numa_fault_tmp(address);
+
+	mutex_unlock(&knumad_mm_mutex);
+
+	down_read(&mm->mmap_sem);
+	if (unlikely(knumad_test_exit(mm)))
+		vma = NULL;
+	else
+		vma = find_vma(mm, address);
+
+	progress++;
+	for (; vma && progress < pages_to_scan; vma = vma->vm_next) {
+		unsigned long start_addr, end_addr;
+		cond_resched();
+		if (unlikely(knumad_test_exit(mm))) {
+			progress++;
+			break;
+		}
+
+		if (!vma->anon_vma || vma_policy(vma)) {
+			progress++;
+			continue;
+		}
+		if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) {
+			progress++;
+			continue;
+		}
+		if (is_vma_temporary_stack(vma)) {
+			progress++;
+			continue;
+		}
+
+		VM_BUG_ON(address & ~PAGE_MASK);
+		if (address < vma->vm_start)
+			address = vma->vm_start;
+
+		start_addr = address;
+		while (address < vma->vm_end) {
+			cond_resched();
+			if (unlikely(knumad_test_exit(mm)))
+				break;
+
+			VM_BUG_ON(address < vma->vm_start ||
+				  address + PAGE_SIZE > vma->vm_end);
+			progress += knuma_scand_pmd(mm, vma, address);
+			/* move to next address */
+			address = (address + PMD_SIZE) & PMD_MASK;
+			if (progress >= pages_to_scan)
+				break;
+		}
+		end_addr = min(address, vma->vm_end);
+
+		/*
+		 * Flush the TLB for the mm to start the NUMA hinting
+		 * page faults after we finish scanning this vma part.
+		 */
+		mmu_notifier_invalidate_range_start(vma->vm_mm, start_addr,
+						    end_addr);
+		flush_tlb_range(vma, start_addr, end_addr);
+		mmu_notifier_invalidate_range_end(vma->vm_mm, start_addr,
+						  end_addr);
+	}
+	up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */
+
+	mutex_lock(&knumad_mm_mutex);
+	VM_BUG_ON(knuma_scand_data.mm != mm);
+	knuma_scand_data.address = address;
+	/*
+	 * Change the current mm if this mm is about to die, or if we
+	 * scanned all vmas of this mm.
+	 */
+	if (knumad_test_exit(mm) || !vma) {
+		mm_autonuma = mm->mm_autonuma;
+		if (mm_autonuma->mm_node.next != &knuma_scand_data.mm_head) {
+			mm_autonuma = list_entry(mm_autonuma->mm_node.next,
+						 struct mm_autonuma, mm_node);
+			knuma_scand_data.mm = mm_autonuma->mm;
+			atomic_inc(&knuma_scand_data.mm->mm_count);
+			knuma_scand_data.address = 0;
+			knuma_scand_data.mm->mm_autonuma->mm_numa_fault_pass++;
+		} else
+			knuma_scand_data.mm = NULL;
+
+		if (knumad_test_exit(mm)) {
+			list_del(&mm->mm_autonuma->mm_node);
+			/* tell autonuma_exit not to list_del */
+			VM_BUG_ON(mm->mm_autonuma->mm != mm);
+			mm->mm_autonuma->mm = NULL;
+			mm_numa_fault_tmp_reset();
+		} else
+			mm_numa_fault_tmp_flush(mm);
+
+		mmdrop(mm);
+	}
+
+	return progress;
+}
+
+static void wake_up_knuma_migrated(void)
+{
+	int nid;
+
+	lru_add_drain();
+	for_each_online_node(nid) {
+		struct pglist_data *pgdat = NODE_DATA(nid);
+		if (pgdat->autonuma_nr_migrate_pages &&
+		    waitqueue_active(&pgdat->autonuma_knuma_migrated_wait))
+			wake_up_interruptible(&pgdat->
+					      autonuma_knuma_migrated_wait);
+	}
+}
+
+static void knuma_scand_disabled(void)
+{
+	if (!autonuma_enabled())
+		wait_event_freezable(knuma_scand_wait,
+				     autonuma_enabled() ||
+				     kthread_should_stop());
+}
+
+static int knuma_scand(void *none)
+{
+	struct mm_struct *mm = NULL;
+	int progress = 0, _progress;
+	unsigned long total_progress = 0;
+
+	set_freezable();
+
+	knuma_scand_disabled();
+
+	/*
+	 * Serialize the knuma_scand_data against
+	 * autonuma_enter/exit().
+	 */
+	mutex_lock(&knumad_mm_mutex);
+
+	for (;;) {
+		if (unlikely(kthread_should_stop()))
+			break;
+
+		/* Do one loop of scanning, keeping track of the progress */
+		_progress = knumad_do_scan();
+		progress += _progress;
+		total_progress += _progress;
+		mutex_unlock(&knumad_mm_mutex);
+
+		/* Check if we completed one full scan pass */
+		if (unlikely(!knuma_scand_data.mm)) {
+			autonuma_printk("knuma_scand %lu\n", total_progress);
+			pages_scanned += total_progress;
+			total_progress = 0;
+			full_scans++;
+
+			wait_event_freezable_timeout(knuma_scand_wait,
+						     kthread_should_stop(),
+						     msecs_to_jiffies(
+						     scan_sleep_pass_millisecs/2));
+			/* flush the last pending pages < pages_to_migrate */
+			wake_up_knuma_migrated();
+			wait_event_freezable_timeout(knuma_scand_wait,
+						     kthread_should_stop(),
+						     msecs_to_jiffies(
+						     scan_sleep_pass_millisecs/2));
+
+			if (autonuma_debug()) {
+				extern void sched_autonuma_dump_mm(void);
+				sched_autonuma_dump_mm();
+			}
+
+			/* wait while there is no pinned mm */
+			knuma_scand_disabled();
+		}
+		if (progress > pages_to_scan) {
+			progress = 0;
+			wait_event_freezable_timeout(knuma_scand_wait,
+						     kthread_should_stop(),
+						     msecs_to_jiffies(
+						     scan_sleep_millisecs));
+		}
+		cond_resched();
+		mutex_lock(&knumad_mm_mutex);
+	}
+
+	mm = knuma_scand_data.mm;
+	knuma_scand_data.mm = NULL;
+	if (mm && knumad_test_exit(mm)) {
+		list_del(&mm->mm_autonuma->mm_node);
+		/* tell autonuma_exit not to list_del */
+		VM_BUG_ON(mm->mm_autonuma->mm != mm);
+		mm->mm_autonuma->mm = NULL;
+	}
+	mutex_unlock(&knumad_mm_mutex);
+
+	if (mm)
+		mmdrop(mm);
+	mm_numa_fault_tmp_reset();
+
+	return 0;
+}
+
+static int isolate_migratepages(struct list_head *migratepages,
+				struct pglist_data *pgdat)
+{
+	int nr = 0, nid;
+	struct list_head *heads = pgdat->autonuma_migrate_head;
+
+	/* FIXME: THP balancing, restart from last nid */
+	for_each_online_node(nid) {
+		struct zone *zone;
+		struct page *page;
+		struct lruvec *lruvec;
+
+		cond_resched();
+		/*
+		 * Let the admin notice if the CPU binding of the
+		 * knuma_migrated kernel threads has been altered in a
+		 * suboptimal way.
+		 */
+		WARN_ONCE(numa_node_id() != pgdat->node_id,
+			  "knuma_migrated%d: the CPU binding of this kernel "
+			  "thread has been altered in a suboptimal way\n",
+			  pgdat->node_id);
+		if (nid == pgdat->node_id) {
+			VM_BUG_ON(!list_empty(&heads[nid]));
+			continue;
+		}
+		if (list_empty(&heads[nid]))
+			continue;
+		/* some page wants to go to this pgdat */
+		/*
+		 * Take the lock with irqs disabled to avoid a lock
+		 * inversion with the lru_lock. The lru_lock is taken
+		 * before the autonuma_migrate_lock in
+		 * split_huge_page. If we didn't disable irqs, the
+		 * lru_lock could be taken by interrupts after we have
+		 * obtained the autonuma_migrate_lock here.
+		 */
+		autonuma_migrate_lock_irq(pgdat->node_id);
+		if (list_empty(&heads[nid])) {
+			autonuma_migrate_unlock_irq(pgdat->node_id);
+			continue;
+		}
+		page = list_entry(heads[nid].prev,
+				  struct page,
+				  autonuma_migrate_node);
+		if (unlikely(!get_page_unless_zero(page))) {
+			/*
+			 * Is getting freed and will remove self from the
+			 * autonuma list shortly, skip it for now.
+			 */
+			list_del(&page->autonuma_migrate_node);
+			list_add(&page->autonuma_migrate_node,
+				 &heads[nid]);
+			autonuma_migrate_unlock_irq(pgdat->node_id);
+			autonuma_printk("autonuma migrate page is free\n");
+			continue;
+		}
+		autonuma_migrate_unlock_irq(pgdat->node_id);
+		if (!PageLRU(page)) {
+			autonuma_printk("autonuma migrate page not in LRU\n");
+			__autonuma_migrate_page_remove(page);
+			put_page(page);
+			continue;
+		}
+
+		VM_BUG_ON(nid != page_to_nid(page));
+
+		if (PageTransHuge(page)) {
+			VM_BUG_ON(!PageAnon(page));
+			/* FIXME: remove split_huge_page */
+			if (unlikely(split_huge_page(page))) {
+				autonuma_printk("autonuma migrate THP free\n");
+				__autonuma_migrate_page_remove(page);
+				put_page(page);
+				continue;
+			}
+		}
+
+		__autonuma_migrate_page_remove(page);
+
+		zone = page_zone(page);
+		spin_lock_irq(&zone->lru_lock);
+
+		/* Must run under the lru_lock and before page isolation */
+		lruvec = mem_cgroup_page_lruvec(page, zone);
+
+		if (!__isolate_lru_page(page, 0)) {
+			VM_BUG_ON(PageTransCompound(page));
+			del_page_from_lru_list(page, lruvec, page_lru(page));
+			inc_zone_state(zone, page_is_file_cache(page) ?
+				       NR_ISOLATED_FILE : NR_ISOLATED_ANON);
+			spin_unlock_irq(&zone->lru_lock);
+			/*
+			 * Pin the page at least until
+			 * __isolate_lru_page succeeds
+			 * (__isolate_lru_page pins it again when it
+			 * succeeds). If we unpin before
+			 * __isolate_lru_page returns, the page could
+			 * be freed and reallocated out from under
+			 * us. Thus our previous checks on the page,
+			 * and split_huge_page, would be worthless.
+			 */
+			put_page(page);
+
+			list_add(&page->lru, migratepages);
+			nr += hpage_nr_pages(page);
+		} else {
+			/* FIXME: losing page, safest and simplest for now */
+			spin_unlock_irq(&zone->lru_lock);
+			put_page(page);
+			autonuma_printk("autonuma migrate page lost\n");
+		}
+	}
+
+	return nr;
+}
+
+static struct page *alloc_migrate_dst_page(struct page *page,
+					   unsigned long data,
+					   int **result)
+{
+	int nid = (int) data;
+	struct page *newpage;
+	newpage = alloc_pages_exact_node(nid,
+					 GFP_HIGHUSER_MOVABLE | GFP_THISNODE,
+					 0);
+	if (newpage)
+		newpage->autonuma_last_nid = page->autonuma_last_nid;
+	return newpage;
+}
+
+static void knumad_do_migrate(struct pglist_data *pgdat)
+{
+	int nr_migrate_pages = 0;
+	LIST_HEAD(migratepages);
+
+	autonuma_printk("nr_migrate_pages %lu to node %d\n",
+			pgdat->autonuma_nr_migrate_pages, pgdat->node_id);
+	do {
+		int isolated = 0;
+		if (autonuma_balance_pgdat(pgdat, nr_migrate_pages))
+			isolated = isolate_migratepages(&migratepages, pgdat);
+		/* FIXME: might need to check too many isolated */
+		if (!isolated)
+			break;
+		nr_migrate_pages += isolated;
+	} while (nr_migrate_pages < pages_to_migrate);
+
+	if (nr_migrate_pages) {
+		int err;
+		autonuma_printk("migrate %d to node %d\n", nr_migrate_pages,
+				pgdat->node_id);
+		pages_migrated += nr_migrate_pages; /* FIXME: per node */
+		err = migrate_pages(&migratepages, alloc_migrate_dst_page,
+				    pgdat->node_id, false, true);
+		if (err)
+			/* FIXME: requeue failed pages */
+			putback_lru_pages(&migratepages);
+	}
+}
+
+static int knuma_migrated(void *arg)
+{
+	struct pglist_data *pgdat = (struct pglist_data *)arg;
+	int nid = pgdat->node_id;
+	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(nowakeup);
+
+	set_freezable();
+
+	for (;;) {
+		if (unlikely(kthread_should_stop()))
+			break;
+		/* FIXME: scan the free levels of this node we may not
+		 * be allowed to receive memory if the wmark of this
+		 * pgdat are below high.  In the future also add
+		 * not-interesting pages like not-accessed pages to
+		 * pgdat->autonuma_migrate_head[pgdat->node_id]; so we
+		 * can move our memory away to other nodes in order
+		 * to satisfy the high-wmark described above (so migration
+		 * can continue).
+		 */
+		knumad_do_migrate(pgdat);
+		if (!pgdat->autonuma_nr_migrate_pages) {
+			wait_event_freezable(
+				pgdat->autonuma_knuma_migrated_wait,
+				pgdat->autonuma_nr_migrate_pages ||
+				kthread_should_stop());
+			autonuma_printk("wake knuma_migrated %d\n", nid);
+		} else
+			wait_event_freezable_timeout(nowakeup,
+						     kthread_should_stop(),
+						     msecs_to_jiffies(
+						     migrate_sleep_millisecs));
+	}
+
+	return 0;
+}
+
+void autonuma_enter(struct mm_struct *mm)
+{
+	if (!autonuma_possible())
+		return;
+
+	mutex_lock(&knumad_mm_mutex);
+	list_add_tail(&mm->mm_autonuma->mm_node, &knuma_scand_data.mm_head);
+	mutex_unlock(&knumad_mm_mutex);
+}
+
+void autonuma_exit(struct mm_struct *mm)
+{
+	bool serialize;
+
+	if (!autonuma_possible())
+		return;
+
+	serialize = false;
+	mutex_lock(&knumad_mm_mutex);
+	if (knuma_scand_data.mm == mm)
+		serialize = true;
+	else if (mm->mm_autonuma->mm) {
+		VM_BUG_ON(mm->mm_autonuma->mm != mm);
+		mm->mm_autonuma->mm = NULL; /* debug */
+		list_del(&mm->mm_autonuma->mm_node);
+	}
+	mutex_unlock(&knumad_mm_mutex);
+
+	if (serialize) {
+		/* prevent the mm to go away under knumad_do_scan main loop */
+		down_write(&mm->mmap_sem);
+		up_write(&mm->mmap_sem);
+	}
+}
+
+static int start_knuma_scand(void)
+{
+	int err = 0;
+	struct task_struct *knumad_thread;
+
+	knuma_scand_data.mm_numa_fault_tmp = kzalloc(mm_autonuma_fault_size(),
+						     GFP_KERNEL);
+	if (!knuma_scand_data.mm_numa_fault_tmp)
+		return -ENOMEM;
+
+	knumad_thread = kthread_run(knuma_scand, NULL, "knuma_scand");
+	if (unlikely(IS_ERR(knumad_thread))) {
+		autonuma_printk(KERN_ERR
+				"knumad: kthread_run(knuma_scand) failed\n");
+		err = PTR_ERR(knumad_thread);
+	}
+	return err;
+}
+
+static int start_knuma_migrated(void)
+{
+	int err = 0;
+	struct task_struct *knumad_thread;
+	int nid;
+
+	for_each_online_node(nid) {
+		knumad_thread = kthread_create_on_node(knuma_migrated,
+						       NODE_DATA(nid),
+						       nid,
+						       "knuma_migrated%d",
+						       nid);
+		if (unlikely(IS_ERR(knumad_thread))) {
+			autonuma_printk(KERN_ERR
+					"knumad: "
+					"kthread_run(knuma_migrated%d) "
+					"failed\n", nid);
+			err = PTR_ERR(knumad_thread);
+		} else {
+			autonuma_printk("cpumask %d %lx\n", nid,
+					cpumask_of_node(nid)->bits[0]);
+			kthread_bind_node(knumad_thread, nid);
+			wake_up_process(knumad_thread);
+		}
+	}
+	return err;
+}
+
+
+#ifdef CONFIG_SYSFS
+
+static ssize_t flag_show(struct kobject *kobj,
+			 struct kobj_attribute *attr, char *buf,
+			 enum autonuma_flag flag)
+{
+	return sprintf(buf, "%d\n",
+		       !!test_bit(flag, &autonuma_flags));
+}
+static ssize_t flag_store(struct kobject *kobj,
+			  struct kobj_attribute *attr,
+			  const char *buf, size_t count,
+			  enum autonuma_flag flag)
+{
+	unsigned long value;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &value);
+	if (ret < 0)
+		return ret;
+	if (value > 1)
+		return -EINVAL;
+
+	if (value)
+		set_bit(flag, &autonuma_flags);
+	else
+		clear_bit(flag, &autonuma_flags);
+
+	return count;
+}
+
+static ssize_t enabled_show(struct kobject *kobj,
+			    struct kobj_attribute *attr, char *buf)
+{
+	return flag_show(kobj, attr, buf, AUTONUMA_ENABLED_FLAG);
+}
+static ssize_t enabled_store(struct kobject *kobj,
+			     struct kobj_attribute *attr,
+			     const char *buf, size_t count)
+{
+	ssize_t ret;
+
+	ret = flag_store(kobj, attr, buf, count, AUTONUMA_ENABLED_FLAG);
+
+	if (ret > 0 && autonuma_enabled())
+		wake_up_interruptible(&knuma_scand_wait);
+
+	return ret;
+}
+static struct kobj_attribute enabled_attr =
+	__ATTR(enabled, 0644, enabled_show, enabled_store);
+
+#define SYSFS_ENTRY(NAME, FLAG)						\
+static ssize_t NAME ## _show(struct kobject *kobj,			\
+			     struct kobj_attribute *attr, char *buf)	\
+{									\
+	return flag_show(kobj, attr, buf, FLAG);			\
+}									\
+									\
+static ssize_t NAME ## _store(struct kobject *kobj,			\
+			      struct kobj_attribute *attr,		\
+			      const char *buf, size_t count)		\
+{									\
+	return flag_store(kobj, attr, buf, count, FLAG);		\
+}									\
+static struct kobj_attribute NAME ## _attr =				\
+	__ATTR(NAME, 0644, NAME ## _show, NAME ## _store);
+
+SYSFS_ENTRY(pmd, AUTONUMA_SCAN_PMD_FLAG);
+SYSFS_ENTRY(debug, AUTONUMA_DEBUG_FLAG);
+#ifdef CONFIG_DEBUG_VM
+SYSFS_ENTRY(load_balance_strict, AUTONUMA_SCHED_LOAD_BALANCE_STRICT_FLAG);
+SYSFS_ENTRY(defer, AUTONUMA_MIGRATE_DEFER_FLAG);
+SYSFS_ENTRY(reset, AUTONUMA_SCHED_RESET_FLAG);
+#endif /* CONFIG_DEBUG_VM */
+
+#undef SYSFS_ENTRY
+
+enum {
+	SYSFS_KNUMA_SCAND_SLEEP_ENTRY,
+	SYSFS_KNUMA_SCAND_PAGES_ENTRY,
+	SYSFS_KNUMA_MIGRATED_SLEEP_ENTRY,
+	SYSFS_KNUMA_MIGRATED_PAGES_ENTRY,
+};
+
+#define SYSFS_ENTRY(NAME, SYSFS_TYPE)				\
+static ssize_t NAME ## _show(struct kobject *kobj,		\
+			     struct kobj_attribute *attr,	\
+			     char *buf)				\
+{								\
+	return sprintf(buf, "%u\n", NAME);			\
+}								\
+static ssize_t NAME ## _store(struct kobject *kobj,		\
+			      struct kobj_attribute *attr,	\
+			      const char *buf, size_t count)	\
+{								\
+	unsigned long val;					\
+	int err;						\
+								\
+	err = strict_strtoul(buf, 10, &val);			\
+	if (err || val > UINT_MAX)				\
+		return -EINVAL;					\
+	switch (SYSFS_TYPE) {					\
+	case SYSFS_KNUMA_SCAND_PAGES_ENTRY:			\
+	case SYSFS_KNUMA_MIGRATED_PAGES_ENTRY:			\
+		if (!val)					\
+			return -EINVAL;				\
+		break;						\
+	}							\
+								\
+	NAME = val;						\
+	switch (SYSFS_TYPE) {					\
+	case SYSFS_KNUMA_SCAND_SLEEP_ENTRY:			\
+		wake_up_interruptible(&knuma_scand_wait);	\
+		break;						\
+	case							\
+		SYSFS_KNUMA_MIGRATED_SLEEP_ENTRY:		\
+		wake_up_knuma_migrated();			\
+		break;						\
+	}							\
+								\
+	return count;						\
+}								\
+static struct kobj_attribute NAME ## _attr =			\
+	__ATTR(NAME, 0644, NAME ## _show, NAME ## _store);
+
+SYSFS_ENTRY(scan_sleep_millisecs, SYSFS_KNUMA_SCAND_SLEEP_ENTRY);
+SYSFS_ENTRY(scan_sleep_pass_millisecs, SYSFS_KNUMA_SCAND_SLEEP_ENTRY);
+SYSFS_ENTRY(pages_to_scan, SYSFS_KNUMA_SCAND_PAGES_ENTRY);
+
+SYSFS_ENTRY(migrate_sleep_millisecs, SYSFS_KNUMA_MIGRATED_SLEEP_ENTRY);
+SYSFS_ENTRY(pages_to_migrate, SYSFS_KNUMA_MIGRATED_PAGES_ENTRY);
+
+#undef SYSFS_ENTRY
+
+static struct attribute *autonuma_attr[] = {
+	&enabled_attr.attr,
+	&debug_attr.attr,
+	NULL,
+};
+static struct attribute_group autonuma_attr_group = {
+	.attrs = autonuma_attr,
+};
+
+#define SYSFS_ENTRY(NAME)					\
+static ssize_t NAME ## _show(struct kobject *kobj,		\
+			     struct kobj_attribute *attr,	\
+			     char *buf)				\
+{								\
+	return sprintf(buf, "%lu\n", NAME);			\
+}								\
+static struct kobj_attribute NAME ## _attr =			\
+	__ATTR_RO(NAME);
+
+SYSFS_ENTRY(full_scans);
+SYSFS_ENTRY(pages_scanned);
+SYSFS_ENTRY(pages_migrated);
+
+#undef SYSFS_ENTRY
+
+static struct attribute *knuma_scand_attr[] = {
+	&scan_sleep_millisecs_attr.attr,
+	&scan_sleep_pass_millisecs_attr.attr,
+	&pages_to_scan_attr.attr,
+	&pages_scanned_attr.attr,
+	&full_scans_attr.attr,
+	&pmd_attr.attr,
+	NULL,
+};
+static struct attribute_group knuma_scand_attr_group = {
+	.attrs = knuma_scand_attr,
+	.name = "knuma_scand",
+};
+
+static struct attribute *knuma_migrated_attr[] = {
+	&migrate_sleep_millisecs_attr.attr,
+	&pages_to_migrate_attr.attr,
+	&pages_migrated_attr.attr,
+#ifdef CONFIG_DEBUG_VM
+	&defer_attr.attr,
+#endif
+	NULL,
+};
+static struct attribute_group knuma_migrated_attr_group = {
+	.attrs = knuma_migrated_attr,
+	.name = "knuma_migrated",
+};
+
+#ifdef CONFIG_DEBUG_VM
+static struct attribute *scheduler_attr[] = {
+	&load_balance_strict_attr.attr,
+	&reset_attr.attr,
+	NULL,
+};
+static struct attribute_group scheduler_attr_group = {
+	.attrs = scheduler_attr,
+	.name = "scheduler",
+};
+#endif
+
+static int __init autonuma_init_sysfs(struct kobject **autonuma_kobj)
+{
+	int err;
+
+	*autonuma_kobj = kobject_create_and_add("autonuma", mm_kobj);
+	if (unlikely(!*autonuma_kobj)) {
+		printk(KERN_ERR "autonuma: failed kobject create\n");
+		return -ENOMEM;
+	}
+
+	err = sysfs_create_group(*autonuma_kobj, &autonuma_attr_group);
+	if (err) {
+		printk(KERN_ERR "autonuma: failed register autonuma group\n");
+		goto delete_obj;
+	}
+
+	err = sysfs_create_group(*autonuma_kobj, &knuma_scand_attr_group);
+	if (err) {
+		printk(KERN_ERR
+		       "autonuma: failed register knuma_scand group\n");
+		goto remove_autonuma;
+	}
+
+	err = sysfs_create_group(*autonuma_kobj, &knuma_migrated_attr_group);
+	if (err) {
+		printk(KERN_ERR
+		       "autonuma: failed register knuma_migrated group\n");
+		goto remove_knuma_scand;
+	}
+
+#ifdef CONFIG_DEBUG_VM
+	err = sysfs_create_group(*autonuma_kobj, &scheduler_attr_group);
+	if (err) {
+		printk(KERN_ERR
+		       "autonuma: failed register scheduler group\n");
+		goto remove_knuma_migrated;
+	}
+#endif
+
+	return 0;
+
+#ifdef CONFIG_DEBUG_VM
+remove_knuma_migrated:
+	sysfs_remove_group(*autonuma_kobj, &knuma_migrated_attr_group);
+#endif
+remove_knuma_scand:
+	sysfs_remove_group(*autonuma_kobj, &knuma_scand_attr_group);
+remove_autonuma:
+	sysfs_remove_group(*autonuma_kobj, &autonuma_attr_group);
+delete_obj:
+	kobject_put(*autonuma_kobj);
+	return err;
+}
+
+static void __init autonuma_exit_sysfs(struct kobject *autonuma_kobj)
+{
+	sysfs_remove_group(autonuma_kobj, &knuma_migrated_attr_group);
+	sysfs_remove_group(autonuma_kobj, &knuma_scand_attr_group);
+	sysfs_remove_group(autonuma_kobj, &autonuma_attr_group);
+	kobject_put(autonuma_kobj);
+}
+#else
+static inline int autonuma_init_sysfs(struct kobject **autonuma_kobj)
+{
+	return 0;
+}
+
+static inline void autonuma_exit_sysfs(struct kobject *autonuma_kobj)
+{
+}
+#endif /* CONFIG_SYSFS */
+
+static int __init noautonuma_setup(char *str)
+{
+	if (autonuma_possible()) {
+		printk("AutoNUMA permanently disabled\n");
+		clear_bit(AUTONUMA_POSSIBLE_FLAG, &autonuma_flags);
+		WARN_ON(autonuma_possible()); /* avoid early crash */
+	}
+	return 1;
+}
+__setup("noautonuma", noautonuma_setup);
+
+static bool autonuma_init_checks_failed(void)
+{
+	/* safety checks on nr_node_ids */
+	int last_nid = find_last_bit(node_states[N_POSSIBLE].bits, MAX_NUMNODES);
+	if (last_nid + 1 != nr_node_ids) {
+		WARN_ON(1);
+		return true;
+	}
+	if (num_possible_nodes() > nr_node_ids) {
+		WARN_ON(1);
+		return true;
+	}
+	return false;
+}
+
+static int __init autonuma_init(void)
+{
+	int err;
+	struct kobject *autonuma_kobj;
+
+	VM_BUG_ON(num_possible_nodes() < 1);
+	if (num_possible_nodes() <= 1 || !autonuma_possible()) {
+		clear_bit(AUTONUMA_POSSIBLE_FLAG, &autonuma_flags);
+		return -EINVAL;
+	} else if (autonuma_init_checks_failed()) {
+		printk("autonuma disengaged: init checks failed\n");
+		clear_bit(AUTONUMA_POSSIBLE_FLAG, &autonuma_flags);
+		return -EINVAL;
+	}
+
+	err = autonuma_init_sysfs(&autonuma_kobj);
+	if (err)
+		return err;
+
+	err = start_knuma_scand();
+	if (err) {
+		printk("failed to start knuma_scand\n");
+		goto out;
+	}
+	err = start_knuma_migrated();
+	if (err) {
+		printk("failed to start knuma_migrated\n");
+		goto out;
+	}
+
+	printk("AutoNUMA initialized successfully\n");
+	return err;
+
+out:
+	autonuma_exit_sysfs(autonuma_kobj);
+	return err;
+}
+module_init(autonuma_init)
+
+static struct kmem_cache *task_autonuma_cachep;
+
+int alloc_task_autonuma(struct task_struct *tsk, struct task_struct *orig,
+			 int node)
+{
+	int err = 1;
+	struct task_autonuma *task_autonuma;
+
+	if (!autonuma_possible())
+		goto no_numa;
+	task_autonuma = kmem_cache_alloc_node(task_autonuma_cachep,
+					      GFP_KERNEL, node);
+	if (!task_autonuma)
+		goto out;
+	if (autonuma_sched_reset())
+		task_autonuma_reset(task_autonuma);
+	else
+		memcpy(task_autonuma, orig->task_autonuma,
+		       task_autonuma_size());
+	tsk->task_autonuma = task_autonuma;
+no_numa:
+	err = 0;
+out:
+	return err;
+}
+
+void free_task_autonuma(struct task_struct *tsk)
+{
+	if (!autonuma_possible()) {
+		BUG_ON(tsk->task_autonuma);
+		return;
+	}
+
+	BUG_ON(!tsk->task_autonuma);
+	kmem_cache_free(task_autonuma_cachep, tsk->task_autonuma);
+	tsk->task_autonuma = NULL;
+}
+
+void __init task_autonuma_init(void)
+{
+	struct task_autonuma *task_autonuma;
+
+	BUG_ON(current != &init_task);
+
+	if (!autonuma_possible())
+		return;
+
+	task_autonuma_cachep =
+		kmem_cache_create("task_autonuma",
+				  task_autonuma_size(), 0,
+				  SLAB_PANIC | SLAB_HWCACHE_ALIGN, NULL);
+
+	task_autonuma = kmem_cache_alloc_node(task_autonuma_cachep,
+					      GFP_KERNEL, numa_node_id());
+	BUG_ON(!task_autonuma);
+	task_autonuma_reset(task_autonuma);
+	BUG_ON(current->task_autonuma);
+	current->task_autonuma = task_autonuma;
+}
+
+static struct kmem_cache *mm_autonuma_cachep;
+
+int alloc_mm_autonuma(struct mm_struct *mm)
+{
+	int err = 1;
+	struct mm_autonuma *mm_autonuma;
+
+	if (!autonuma_possible())
+		goto no_numa;
+	mm_autonuma = kmem_cache_alloc(mm_autonuma_cachep, GFP_KERNEL);
+	if (!mm_autonuma)
+		goto out;
+	if (autonuma_sched_reset() || !mm->mm_autonuma)
+		mm_autonuma_reset(mm_autonuma);
+	else
+		memcpy(mm_autonuma, mm->mm_autonuma, mm_autonuma_size());
+
+	/*
+	 * We're not leaking memory here, if mm->mm_autonuma is not
+	 * zero it's a not refcounted copy of the parent's
+	 * mm->mm_autonuma pointer.
+	 */
+	mm->mm_autonuma = mm_autonuma;
+	mm_autonuma->mm = mm;
+no_numa:
+	err = 0;
+out:
+	return err;
+}
+
+void free_mm_autonuma(struct mm_struct *mm)
+{
+	if (!autonuma_possible()) {
+		BUG_ON(mm->mm_autonuma);
+		return;
+	}
+
+	BUG_ON(!mm->mm_autonuma);
+	kmem_cache_free(mm_autonuma_cachep, mm->mm_autonuma);
+	mm->mm_autonuma = NULL;
+}
+
+void __init mm_autonuma_init(void)
+{
+	BUG_ON(current != &init_task);
+	BUG_ON(current->mm);
+
+	if (!autonuma_possible())
+		return;
+
+	mm_autonuma_cachep =
+		kmem_cache_create("mm_autonuma",
+				  mm_autonuma_size(), 0,
+				  SLAB_PANIC | SLAB_HWCACHE_ALIGN, NULL);
+}
--
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