#include <linux/highmem.h>
#include <linux/nodemask.h>
#include <linux/pagemap.h>
+#include <linux/mempolicy.h>
+#include <linux/cpuset.h>
+#include <linux/mutex.h>
+
#include <asm/page.h>
#include <asm/pgtable.h>
#include <linux/hugetlb.h>
+#include "internal.h"
const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
-static unsigned long nr_huge_pages, free_huge_pages;
+static unsigned long nr_huge_pages, free_huge_pages, resv_huge_pages;
+static unsigned long surplus_huge_pages;
+static unsigned long nr_overcommit_huge_pages;
unsigned long max_huge_pages;
+unsigned long sysctl_overcommit_huge_pages;
static struct list_head hugepage_freelists[MAX_NUMNODES];
static unsigned int nr_huge_pages_node[MAX_NUMNODES];
static unsigned int free_huge_pages_node[MAX_NUMNODES];
+static unsigned int surplus_huge_pages_node[MAX_NUMNODES];
+static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
+unsigned long hugepages_treat_as_movable;
+static int hugetlb_next_nid;
+
+/*
+ * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
+ */
static DEFINE_SPINLOCK(hugetlb_lock);
+static void clear_huge_page(struct page *page, unsigned long addr)
+{
+ int i;
+
+ might_sleep();
+ for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) {
+ cond_resched();
+ clear_user_highpage(page + i, addr + i * PAGE_SIZE);
+ }
+}
+
+static void copy_huge_page(struct page *dst, struct page *src,
+ unsigned long addr, struct vm_area_struct *vma)
+{
+ int i;
+
+ might_sleep();
+ for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) {
+ cond_resched();
+ copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
+ }
+}
+
static void enqueue_huge_page(struct page *page)
{
int nid = page_to_nid(page);
static struct page *dequeue_huge_page(void)
{
- int nid = numa_node_id();
+ int nid;
struct page *page = NULL;
- if (list_empty(&hugepage_freelists[nid])) {
- for (nid = 0; nid < MAX_NUMNODES; ++nid)
- if (!list_empty(&hugepage_freelists[nid]))
- break;
+ for (nid = 0; nid < MAX_NUMNODES; ++nid) {
+ if (!list_empty(&hugepage_freelists[nid])) {
+ page = list_entry(hugepage_freelists[nid].next,
+ struct page, lru);
+ list_del(&page->lru);
+ free_huge_pages--;
+ free_huge_pages_node[nid]--;
+ break;
+ }
}
- if (nid >= 0 && nid < MAX_NUMNODES &&
- !list_empty(&hugepage_freelists[nid])) {
- page = list_entry(hugepage_freelists[nid].next,
- struct page, lru);
- list_del(&page->lru);
- free_huge_pages--;
- free_huge_pages_node[nid]--;
+ return page;
+}
+
+static struct page *dequeue_huge_page_vma(struct vm_area_struct *vma,
+ unsigned long address)
+{
+ int nid;
+ struct page *page = NULL;
+ struct mempolicy *mpol;
+ struct zonelist *zonelist = huge_zonelist(vma, address,
+ htlb_alloc_mask, &mpol);
+ struct zone **z;
+
+ for (z = zonelist->zones; *z; z++) {
+ nid = zone_to_nid(*z);
+ if (cpuset_zone_allowed_softwall(*z, htlb_alloc_mask) &&
+ !list_empty(&hugepage_freelists[nid])) {
+ page = list_entry(hugepage_freelists[nid].next,
+ struct page, lru);
+ list_del(&page->lru);
+ free_huge_pages--;
+ free_huge_pages_node[nid]--;
+ if (vma && vma->vm_flags & VM_MAYSHARE)
+ resv_huge_pages--;
+ break;
+ }
}
+ mpol_free(mpol); /* unref if mpol !NULL */
return page;
}
-static struct page *alloc_fresh_huge_page(void)
+static void update_and_free_page(struct page *page)
+{
+ int i;
+ nr_huge_pages--;
+ nr_huge_pages_node[page_to_nid(page)]--;
+ for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
+ page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
+ 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
+ 1 << PG_private | 1<< PG_writeback);
+ }
+ set_compound_page_dtor(page, NULL);
+ set_page_refcounted(page);
+ __free_pages(page, HUGETLB_PAGE_ORDER);
+}
+
+static void free_huge_page(struct page *page)
+{
+ int nid = page_to_nid(page);
+ struct address_space *mapping;
+
+ mapping = (struct address_space *) page_private(page);
+ set_page_private(page, 0);
+ BUG_ON(page_count(page));
+ INIT_LIST_HEAD(&page->lru);
+
+ spin_lock(&hugetlb_lock);
+ if (surplus_huge_pages_node[nid]) {
+ update_and_free_page(page);
+ surplus_huge_pages--;
+ surplus_huge_pages_node[nid]--;
+ } else {
+ enqueue_huge_page(page);
+ }
+ spin_unlock(&hugetlb_lock);
+ if (mapping)
+ hugetlb_put_quota(mapping, 1);
+}
+
+/*
+ * Increment or decrement surplus_huge_pages. Keep node-specific counters
+ * balanced by operating on them in a round-robin fashion.
+ * Returns 1 if an adjustment was made.
+ */
+static int adjust_pool_surplus(int delta)
+{
+ static int prev_nid;
+ int nid = prev_nid;
+ int ret = 0;
+
+ VM_BUG_ON(delta != -1 && delta != 1);
+ do {
+ nid = next_node(nid, node_online_map);
+ if (nid == MAX_NUMNODES)
+ nid = first_node(node_online_map);
+
+ /* To shrink on this node, there must be a surplus page */
+ if (delta < 0 && !surplus_huge_pages_node[nid])
+ continue;
+ /* Surplus cannot exceed the total number of pages */
+ if (delta > 0 && surplus_huge_pages_node[nid] >=
+ nr_huge_pages_node[nid])
+ continue;
+
+ surplus_huge_pages += delta;
+ surplus_huge_pages_node[nid] += delta;
+ ret = 1;
+ break;
+ } while (nid != prev_nid);
+
+ prev_nid = nid;
+ return ret;
+}
+
+static struct page *alloc_fresh_huge_page_node(int nid)
{
- static int nid = 0;
struct page *page;
- page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
- HUGETLB_PAGE_ORDER);
- nid = (nid + 1) % num_online_nodes();
+
+ page = alloc_pages_node(nid,
+ htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN,
+ HUGETLB_PAGE_ORDER);
if (page) {
+ set_compound_page_dtor(page, free_huge_page);
+ spin_lock(&hugetlb_lock);
nr_huge_pages++;
- nr_huge_pages_node[page_to_nid(page)]++;
+ nr_huge_pages_node[nid]++;
+ spin_unlock(&hugetlb_lock);
+ put_page(page); /* free it into the hugepage allocator */
}
+
return page;
}
-void free_huge_page(struct page *page)
+static int alloc_fresh_huge_page(void)
{
- BUG_ON(page_count(page));
+ struct page *page;
+ int start_nid;
+ int next_nid;
+ int ret = 0;
- INIT_LIST_HEAD(&page->lru);
- page[1].mapping = NULL;
+ start_nid = hugetlb_next_nid;
- spin_lock(&hugetlb_lock);
- enqueue_huge_page(page);
- spin_unlock(&hugetlb_lock);
+ do {
+ page = alloc_fresh_huge_page_node(hugetlb_next_nid);
+ if (page)
+ ret = 1;
+ /*
+ * Use a helper variable to find the next node and then
+ * copy it back to hugetlb_next_nid afterwards:
+ * otherwise there's a window in which a racer might
+ * pass invalid nid MAX_NUMNODES to alloc_pages_node.
+ * But we don't need to use a spin_lock here: it really
+ * doesn't matter if occasionally a racer chooses the
+ * same nid as we do. Move nid forward in the mask even
+ * if we just successfully allocated a hugepage so that
+ * the next caller gets hugepages on the next node.
+ */
+ next_nid = next_node(hugetlb_next_nid, node_online_map);
+ if (next_nid == MAX_NUMNODES)
+ next_nid = first_node(node_online_map);
+ hugetlb_next_nid = next_nid;
+ } while (!page && hugetlb_next_nid != start_nid);
+
+ return ret;
}
-struct page *alloc_huge_page(void)
+static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma,
+ unsigned long address)
{
struct page *page;
- int i;
+ unsigned int nid;
+ /*
+ * Assume we will successfully allocate the surplus page to
+ * prevent racing processes from causing the surplus to exceed
+ * overcommit
+ *
+ * This however introduces a different race, where a process B
+ * tries to grow the static hugepage pool while alloc_pages() is
+ * called by process A. B will only examine the per-node
+ * counters in determining if surplus huge pages can be
+ * converted to normal huge pages in adjust_pool_surplus(). A
+ * won't be able to increment the per-node counter, until the
+ * lock is dropped by B, but B doesn't drop hugetlb_lock until
+ * no more huge pages can be converted from surplus to normal
+ * state (and doesn't try to convert again). Thus, we have a
+ * case where a surplus huge page exists, the pool is grown, and
+ * the surplus huge page still exists after, even though it
+ * should just have been converted to a normal huge page. This
+ * does not leak memory, though, as the hugepage will be freed
+ * once it is out of use. It also does not allow the counters to
+ * go out of whack in adjust_pool_surplus() as we don't modify
+ * the node values until we've gotten the hugepage and only the
+ * per-node value is checked there.
+ */
spin_lock(&hugetlb_lock);
- page = dequeue_huge_page();
- if (!page) {
+ if (surplus_huge_pages >= nr_overcommit_huge_pages) {
spin_unlock(&hugetlb_lock);
return NULL;
+ } else {
+ nr_huge_pages++;
+ surplus_huge_pages++;
+ }
+ spin_unlock(&hugetlb_lock);
+
+ page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN,
+ HUGETLB_PAGE_ORDER);
+
+ spin_lock(&hugetlb_lock);
+ if (page) {
+ /*
+ * This page is now managed by the hugetlb allocator and has
+ * no users -- drop the buddy allocator's reference.
+ */
+ put_page_testzero(page);
+ VM_BUG_ON(page_count(page));
+ nid = page_to_nid(page);
+ set_compound_page_dtor(page, free_huge_page);
+ /*
+ * We incremented the global counters already
+ */
+ nr_huge_pages_node[nid]++;
+ surplus_huge_pages_node[nid]++;
+ } else {
+ nr_huge_pages--;
+ surplus_huge_pages--;
+ }
+ spin_unlock(&hugetlb_lock);
+
+ return page;
+}
+
+/*
+ * Increase the hugetlb pool such that it can accomodate a reservation
+ * of size 'delta'.
+ */
+static int gather_surplus_pages(int delta)
+{
+ struct list_head surplus_list;
+ struct page *page, *tmp;
+ int ret, i;
+ int needed, allocated;
+
+ needed = (resv_huge_pages + delta) - free_huge_pages;
+ if (needed <= 0) {
+ resv_huge_pages += delta;
+ return 0;
+ }
+
+ allocated = 0;
+ INIT_LIST_HEAD(&surplus_list);
+
+ ret = -ENOMEM;
+retry:
+ spin_unlock(&hugetlb_lock);
+ for (i = 0; i < needed; i++) {
+ page = alloc_buddy_huge_page(NULL, 0);
+ if (!page) {
+ /*
+ * We were not able to allocate enough pages to
+ * satisfy the entire reservation so we free what
+ * we've allocated so far.
+ */
+ spin_lock(&hugetlb_lock);
+ needed = 0;
+ goto free;
+ }
+
+ list_add(&page->lru, &surplus_list);
+ }
+ allocated += needed;
+
+ /*
+ * After retaking hugetlb_lock, we need to recalculate 'needed'
+ * because either resv_huge_pages or free_huge_pages may have changed.
+ */
+ spin_lock(&hugetlb_lock);
+ needed = (resv_huge_pages + delta) - (free_huge_pages + allocated);
+ if (needed > 0)
+ goto retry;
+
+ /*
+ * The surplus_list now contains _at_least_ the number of extra pages
+ * needed to accomodate the reservation. Add the appropriate number
+ * of pages to the hugetlb pool and free the extras back to the buddy
+ * allocator. Commit the entire reservation here to prevent another
+ * process from stealing the pages as they are added to the pool but
+ * before they are reserved.
+ */
+ needed += allocated;
+ resv_huge_pages += delta;
+ ret = 0;
+free:
+ list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
+ list_del(&page->lru);
+ if ((--needed) >= 0)
+ enqueue_huge_page(page);
+ else {
+ /*
+ * The page has a reference count of zero already, so
+ * call free_huge_page directly instead of using
+ * put_page. This must be done with hugetlb_lock
+ * unlocked which is safe because free_huge_page takes
+ * hugetlb_lock before deciding how to free the page.
+ */
+ spin_unlock(&hugetlb_lock);
+ free_huge_page(page);
+ spin_lock(&hugetlb_lock);
+ }
+ }
+
+ return ret;
+}
+
+/*
+ * When releasing a hugetlb pool reservation, any surplus pages that were
+ * allocated to satisfy the reservation must be explicitly freed if they were
+ * never used.
+ */
+static void return_unused_surplus_pages(unsigned long unused_resv_pages)
+{
+ static int nid = -1;
+ struct page *page;
+ unsigned long nr_pages;
+
+ /*
+ * We want to release as many surplus pages as possible, spread
+ * evenly across all nodes. Iterate across all nodes until we
+ * can no longer free unreserved surplus pages. This occurs when
+ * the nodes with surplus pages have no free pages.
+ */
+ unsigned long remaining_iterations = num_online_nodes();
+
+ /* Uncommit the reservation */
+ resv_huge_pages -= unused_resv_pages;
+
+ nr_pages = min(unused_resv_pages, surplus_huge_pages);
+
+ while (remaining_iterations-- && nr_pages) {
+ nid = next_node(nid, node_online_map);
+ if (nid == MAX_NUMNODES)
+ nid = first_node(node_online_map);
+
+ if (!surplus_huge_pages_node[nid])
+ continue;
+
+ if (!list_empty(&hugepage_freelists[nid])) {
+ page = list_entry(hugepage_freelists[nid].next,
+ struct page, lru);
+ list_del(&page->lru);
+ update_and_free_page(page);
+ free_huge_pages--;
+ free_huge_pages_node[nid]--;
+ surplus_huge_pages--;
+ surplus_huge_pages_node[nid]--;
+ nr_pages--;
+ remaining_iterations = num_online_nodes();
+ }
}
+}
+
+
+static struct page *alloc_huge_page_shared(struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ struct page *page;
+
+ spin_lock(&hugetlb_lock);
+ page = dequeue_huge_page_vma(vma, addr);
+ spin_unlock(&hugetlb_lock);
+ return page ? page : ERR_PTR(-VM_FAULT_OOM);
+}
+
+static struct page *alloc_huge_page_private(struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ struct page *page = NULL;
+
+ if (hugetlb_get_quota(vma->vm_file->f_mapping, 1))
+ return ERR_PTR(-VM_FAULT_SIGBUS);
+
+ spin_lock(&hugetlb_lock);
+ if (free_huge_pages > resv_huge_pages)
+ page = dequeue_huge_page_vma(vma, addr);
spin_unlock(&hugetlb_lock);
- set_page_count(page, 1);
- page[1].mapping = (void *)free_huge_page;
- for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i)
- clear_highpage(&page[i]);
+ if (!page) {
+ page = alloc_buddy_huge_page(vma, addr);
+ if (!page) {
+ hugetlb_put_quota(vma->vm_file->f_mapping, 1);
+ return ERR_PTR(-VM_FAULT_OOM);
+ }
+ }
+ return page;
+}
+
+static struct page *alloc_huge_page(struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ struct page *page;
+ struct address_space *mapping = vma->vm_file->f_mapping;
+
+ if (vma->vm_flags & VM_MAYSHARE)
+ page = alloc_huge_page_shared(vma, addr);
+ else
+ page = alloc_huge_page_private(vma, addr);
+
+ if (!IS_ERR(page)) {
+ set_page_refcounted(page);
+ set_page_private(page, (unsigned long) mapping);
+ }
return page;
}
static int __init hugetlb_init(void)
{
unsigned long i;
- struct page *page;
+
+ if (HPAGE_SHIFT == 0)
+ return 0;
for (i = 0; i < MAX_NUMNODES; ++i)
INIT_LIST_HEAD(&hugepage_freelists[i]);
+ hugetlb_next_nid = first_node(node_online_map);
+
for (i = 0; i < max_huge_pages; ++i) {
- page = alloc_fresh_huge_page();
- if (!page)
+ if (!alloc_fresh_huge_page())
break;
- spin_lock(&hugetlb_lock);
- enqueue_huge_page(page);
- spin_unlock(&hugetlb_lock);
}
max_huge_pages = free_huge_pages = nr_huge_pages = i;
printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
}
__setup("hugepages=", hugetlb_setup);
-#ifdef CONFIG_SYSCTL
-static void update_and_free_page(struct page *page)
+static unsigned int cpuset_mems_nr(unsigned int *array)
{
- int i;
- nr_huge_pages--;
- nr_huge_pages_node[page_zone(page)->zone_pgdat->node_id]--;
- for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
- page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
- 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
- 1 << PG_private | 1<< PG_writeback);
- set_page_count(&page[i], 0);
- }
- set_page_count(page, 1);
- __free_pages(page, HUGETLB_PAGE_ORDER);
+ int node;
+ unsigned int nr = 0;
+
+ for_each_node_mask(node, cpuset_current_mems_allowed)
+ nr += array[node];
+
+ return nr;
}
+#ifdef CONFIG_SYSCTL
#ifdef CONFIG_HIGHMEM
static void try_to_free_low(unsigned long count)
{
- int i, nid;
+ int i;
+
for (i = 0; i < MAX_NUMNODES; ++i) {
struct page *page, *next;
list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
+ if (count >= nr_huge_pages)
+ return;
if (PageHighMem(page))
continue;
list_del(&page->lru);
update_and_free_page(page);
- nid = page_zone(page)->zone_pgdat->node_id;
free_huge_pages--;
- free_huge_pages_node[nid]--;
- if (count >= nr_huge_pages)
- return;
+ free_huge_pages_node[page_to_nid(page)]--;
}
}
}
}
#endif
+#define persistent_huge_pages (nr_huge_pages - surplus_huge_pages)
static unsigned long set_max_huge_pages(unsigned long count)
{
- while (count > nr_huge_pages) {
- struct page *page = alloc_fresh_huge_page();
- if (!page)
- return nr_huge_pages;
- spin_lock(&hugetlb_lock);
- enqueue_huge_page(page);
+ unsigned long min_count, ret;
+
+ /*
+ * Increase the pool size
+ * First take pages out of surplus state. Then make up the
+ * remaining difference by allocating fresh huge pages.
+ *
+ * We might race with alloc_buddy_huge_page() here and be unable
+ * to convert a surplus huge page to a normal huge page. That is
+ * not critical, though, it just means the overall size of the
+ * pool might be one hugepage larger than it needs to be, but
+ * within all the constraints specified by the sysctls.
+ */
+ spin_lock(&hugetlb_lock);
+ while (surplus_huge_pages && count > persistent_huge_pages) {
+ if (!adjust_pool_surplus(-1))
+ break;
+ }
+
+ while (count > persistent_huge_pages) {
+ int ret;
+ /*
+ * If this allocation races such that we no longer need the
+ * page, free_huge_page will handle it by freeing the page
+ * and reducing the surplus.
+ */
spin_unlock(&hugetlb_lock);
+ ret = alloc_fresh_huge_page();
+ spin_lock(&hugetlb_lock);
+ if (!ret)
+ goto out;
+
}
- if (count >= nr_huge_pages)
- return nr_huge_pages;
- spin_lock(&hugetlb_lock);
- try_to_free_low(count);
- while (count < nr_huge_pages) {
+ /*
+ * Decrease the pool size
+ * First return free pages to the buddy allocator (being careful
+ * to keep enough around to satisfy reservations). Then place
+ * pages into surplus state as needed so the pool will shrink
+ * to the desired size as pages become free.
+ *
+ * By placing pages into the surplus state independent of the
+ * overcommit value, we are allowing the surplus pool size to
+ * exceed overcommit. There are few sane options here. Since
+ * alloc_buddy_huge_page() is checking the global counter,
+ * though, we'll note that we're not allowed to exceed surplus
+ * and won't grow the pool anywhere else. Not until one of the
+ * sysctls are changed, or the surplus pages go out of use.
+ */
+ min_count = resv_huge_pages + nr_huge_pages - free_huge_pages;
+ min_count = max(count, min_count);
+ try_to_free_low(min_count);
+ while (min_count < persistent_huge_pages) {
struct page *page = dequeue_huge_page();
if (!page)
break;
update_and_free_page(page);
}
+ while (count < persistent_huge_pages) {
+ if (!adjust_pool_surplus(1))
+ break;
+ }
+out:
+ ret = persistent_huge_pages;
spin_unlock(&hugetlb_lock);
- return nr_huge_pages;
+ return ret;
}
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
max_huge_pages = set_max_huge_pages(max_huge_pages);
return 0;
}
+
+int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
+ struct file *file, void __user *buffer,
+ size_t *length, loff_t *ppos)
+{
+ proc_dointvec(table, write, file, buffer, length, ppos);
+ if (hugepages_treat_as_movable)
+ htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
+ else
+ htlb_alloc_mask = GFP_HIGHUSER;
+ return 0;
+}
+
+int hugetlb_overcommit_handler(struct ctl_table *table, int write,
+ struct file *file, void __user *buffer,
+ size_t *length, loff_t *ppos)
+{
+ proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
+ spin_lock(&hugetlb_lock);
+ nr_overcommit_huge_pages = sysctl_overcommit_huge_pages;
+ spin_unlock(&hugetlb_lock);
+ return 0;
+}
+
#endif /* CONFIG_SYSCTL */
int hugetlb_report_meminfo(char *buf)
return sprintf(buf,
"HugePages_Total: %5lu\n"
"HugePages_Free: %5lu\n"
+ "HugePages_Rsvd: %5lu\n"
+ "HugePages_Surp: %5lu\n"
"Hugepagesize: %5lu kB\n",
nr_huge_pages,
free_huge_pages,
+ resv_huge_pages,
+ surplus_huge_pages,
HPAGE_SIZE/1024);
}
{
return sprintf(buf,
"Node %d HugePages_Total: %5u\n"
- "Node %d HugePages_Free: %5u\n",
+ "Node %d HugePages_Free: %5u\n"
+ "Node %d HugePages_Surp: %5u\n",
nid, nr_huge_pages_node[nid],
- nid, free_huge_pages_node[nid]);
-}
-
-int is_hugepage_mem_enough(size_t size)
-{
- return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages;
+ nid, free_huge_pages_node[nid],
+ nid, surplus_huge_pages_node[nid]);
}
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
{
return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
}
-EXPORT_SYMBOL(hugetlb_total_pages);
/*
* We cannot handle pagefaults against hugetlb pages at all. They cause
* hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
* this far.
*/
-static struct page *hugetlb_nopage(struct vm_area_struct *vma,
- unsigned long address, int *unused)
+static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
BUG();
- return NULL;
+ return 0;
}
struct vm_operations_struct hugetlb_vm_ops = {
- .nopage = hugetlb_nopage,
+ .fault = hugetlb_vm_op_fault,
};
-static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page)
+static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
+ int writable)
{
pte_t entry;
- if (vma->vm_flags & VM_WRITE) {
+ if (writable) {
entry =
pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
} else {
return entry;
}
+static void set_huge_ptep_writable(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep)
+{
+ pte_t entry;
+
+ entry = pte_mkwrite(pte_mkdirty(*ptep));
+ if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {
+ update_mmu_cache(vma, address, entry);
+ }
+}
+
+
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
struct vm_area_struct *vma)
{
pte_t *src_pte, *dst_pte, entry;
struct page *ptepage;
unsigned long addr;
+ int cow;
+
+ cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
src_pte = huge_pte_offset(src, addr);
dst_pte = huge_pte_alloc(dst, addr);
if (!dst_pte)
goto nomem;
+
+ /* If the pagetables are shared don't copy or take references */
+ if (dst_pte == src_pte)
+ continue;
+
spin_lock(&dst->page_table_lock);
spin_lock(&src->page_table_lock);
if (!pte_none(*src_pte)) {
+ if (cow)
+ ptep_set_wrprotect(src, addr, src_pte);
entry = *src_pte;
ptepage = pte_page(entry);
get_page(ptepage);
- add_mm_counter(dst, file_rss, HPAGE_SIZE / PAGE_SIZE);
set_huge_pte_at(dst, addr, dst_pte, entry);
}
spin_unlock(&src->page_table_lock);
return -ENOMEM;
}
-void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
- unsigned long end)
+void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
pte_t *ptep;
pte_t pte;
struct page *page;
+ struct page *tmp;
+ /*
+ * A page gathering list, protected by per file i_mmap_lock. The
+ * lock is used to avoid list corruption from multiple unmapping
+ * of the same page since we are using page->lru.
+ */
+ LIST_HEAD(page_list);
WARN_ON(!is_vm_hugetlb_page(vma));
BUG_ON(start & ~HPAGE_MASK);
BUG_ON(end & ~HPAGE_MASK);
spin_lock(&mm->page_table_lock);
-
- /* Update high watermark before we lower rss */
- update_hiwater_rss(mm);
-
for (address = start; address < end; address += HPAGE_SIZE) {
ptep = huge_pte_offset(mm, address);
if (!ptep)
continue;
+ if (huge_pmd_unshare(mm, &address, ptep))
+ continue;
+
pte = huge_ptep_get_and_clear(mm, address, ptep);
if (pte_none(pte))
continue;
page = pte_page(pte);
- put_page(page);
- add_mm_counter(mm, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE));
+ if (pte_dirty(pte))
+ set_page_dirty(page);
+ list_add(&page->lru, &page_list);
}
-
spin_unlock(&mm->page_table_lock);
flush_tlb_range(vma, start, end);
+ list_for_each_entry_safe(page, tmp, &page_list, lru) {
+ list_del(&page->lru);
+ put_page(page);
+ }
}
-static struct page *find_lock_huge_page(struct address_space *mapping,
- unsigned long idx)
+void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end)
{
- struct page *page;
- int err;
- struct inode *inode = mapping->host;
- unsigned long size;
+ /*
+ * It is undesirable to test vma->vm_file as it should be non-null
+ * for valid hugetlb area. However, vm_file will be NULL in the error
+ * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
+ * do_mmap_pgoff() nullifies vma->vm_file before calling this function
+ * to clean up. Since no pte has actually been setup, it is safe to
+ * do nothing in this case.
+ */
+ if (vma->vm_file) {
+ spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
+ __unmap_hugepage_range(vma, start, end);
+ spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
+ }
+}
-retry:
- page = find_lock_page(mapping, idx);
- if (page)
- goto out;
+static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep, pte_t pte)
+{
+ struct page *old_page, *new_page;
+ int avoidcopy;
- /* Check to make sure the mapping hasn't been truncated */
- size = i_size_read(inode) >> HPAGE_SHIFT;
- if (idx >= size)
- goto out;
+ old_page = pte_page(pte);
- if (hugetlb_get_quota(mapping))
- goto out;
- page = alloc_huge_page();
- if (!page) {
- hugetlb_put_quota(mapping);
- goto out;
+ /* If no-one else is actually using this page, avoid the copy
+ * and just make the page writable */
+ avoidcopy = (page_count(old_page) == 1);
+ if (avoidcopy) {
+ set_huge_ptep_writable(vma, address, ptep);
+ return 0;
}
- err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
- if (err) {
- put_page(page);
- hugetlb_put_quota(mapping);
- if (err == -EEXIST)
- goto retry;
- page = NULL;
+ page_cache_get(old_page);
+ new_page = alloc_huge_page(vma, address);
+
+ if (IS_ERR(new_page)) {
+ page_cache_release(old_page);
+ return -PTR_ERR(new_page);
}
-out:
- return page;
+
+ spin_unlock(&mm->page_table_lock);
+ copy_huge_page(new_page, old_page, address, vma);
+ __SetPageUptodate(new_page);
+ spin_lock(&mm->page_table_lock);
+
+ ptep = huge_pte_offset(mm, address & HPAGE_MASK);
+ if (likely(pte_same(*ptep, pte))) {
+ /* Break COW */
+ set_huge_pte_at(mm, address, ptep,
+ make_huge_pte(vma, new_page, 1));
+ /* Make the old page be freed below */
+ new_page = old_page;
+ }
+ page_cache_release(new_page);
+ page_cache_release(old_page);
+ return 0;
}
-int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, int write_access)
+static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep, int write_access)
{
int ret = VM_FAULT_SIGBUS;
unsigned long idx;
unsigned long size;
- pte_t *pte;
struct page *page;
struct address_space *mapping;
-
- pte = huge_pte_alloc(mm, address);
- if (!pte)
- goto out;
+ pte_t new_pte;
mapping = vma->vm_file->f_mapping;
idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
* Use page lock to guard against racing truncation
* before we get page_table_lock.
*/
- page = find_lock_huge_page(mapping, idx);
- if (!page)
- goto out;
+retry:
+ page = find_lock_page(mapping, idx);
+ if (!page) {
+ size = i_size_read(mapping->host) >> HPAGE_SHIFT;
+ if (idx >= size)
+ goto out;
+ page = alloc_huge_page(vma, address);
+ if (IS_ERR(page)) {
+ ret = -PTR_ERR(page);
+ goto out;
+ }
+ clear_huge_page(page, address);
+ __SetPageUptodate(page);
+
+ if (vma->vm_flags & VM_SHARED) {
+ int err;
+ struct inode *inode = mapping->host;
+
+ err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
+ if (err) {
+ put_page(page);
+ if (err == -EEXIST)
+ goto retry;
+ goto out;
+ }
+
+ spin_lock(&inode->i_lock);
+ inode->i_blocks += BLOCKS_PER_HUGEPAGE;
+ spin_unlock(&inode->i_lock);
+ } else
+ lock_page(page);
+ }
spin_lock(&mm->page_table_lock);
size = i_size_read(mapping->host) >> HPAGE_SHIFT;
if (idx >= size)
goto backout;
- ret = VM_FAULT_MINOR;
- if (!pte_none(*pte))
+ ret = 0;
+ if (!pte_none(*ptep))
goto backout;
- add_mm_counter(mm, file_rss, HPAGE_SIZE / PAGE_SIZE);
- set_huge_pte_at(mm, address, pte, make_huge_pte(vma, page));
+ new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
+ && (vma->vm_flags & VM_SHARED)));
+ set_huge_pte_at(mm, address, ptep, new_pte);
+
+ if (write_access && !(vma->vm_flags & VM_SHARED)) {
+ /* Optimization, do the COW without a second fault */
+ ret = hugetlb_cow(mm, vma, address, ptep, new_pte);
+ }
+
spin_unlock(&mm->page_table_lock);
unlock_page(page);
out:
backout:
spin_unlock(&mm->page_table_lock);
- hugetlb_put_quota(mapping);
unlock_page(page);
put_page(page);
goto out;
}
+int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, int write_access)
+{
+ pte_t *ptep;
+ pte_t entry;
+ int ret;
+ static DEFINE_MUTEX(hugetlb_instantiation_mutex);
+
+ ptep = huge_pte_alloc(mm, address);
+ if (!ptep)
+ return VM_FAULT_OOM;
+
+ /*
+ * Serialize hugepage allocation and instantiation, so that we don't
+ * get spurious allocation failures if two CPUs race to instantiate
+ * the same page in the page cache.
+ */
+ mutex_lock(&hugetlb_instantiation_mutex);
+ entry = *ptep;
+ if (pte_none(entry)) {
+ ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
+ mutex_unlock(&hugetlb_instantiation_mutex);
+ return ret;
+ }
+
+ ret = 0;
+
+ spin_lock(&mm->page_table_lock);
+ /* Check for a racing update before calling hugetlb_cow */
+ if (likely(pte_same(entry, *ptep)))
+ if (write_access && !pte_write(entry))
+ ret = hugetlb_cow(mm, vma, address, ptep, entry);
+ spin_unlock(&mm->page_table_lock);
+ mutex_unlock(&hugetlb_instantiation_mutex);
+
+ return ret;
+}
+
int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page **pages, struct vm_area_struct **vmas,
- unsigned long *position, int *length, int i)
+ unsigned long *position, int *length, int i,
+ int write)
{
- unsigned long vpfn, vaddr = *position;
+ unsigned long pfn_offset;
+ unsigned long vaddr = *position;
int remainder = *length;
- vpfn = vaddr/PAGE_SIZE;
spin_lock(&mm->page_table_lock);
while (vaddr < vma->vm_end && remainder) {
pte_t *pte;
*/
pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
- if (!pte || pte_none(*pte)) {
+ if (!pte || pte_none(*pte) || (write && !pte_write(*pte))) {
int ret;
spin_unlock(&mm->page_table_lock);
- ret = hugetlb_fault(mm, vma, vaddr, 0);
+ ret = hugetlb_fault(mm, vma, vaddr, write);
spin_lock(&mm->page_table_lock);
- if (ret == VM_FAULT_MINOR)
+ if (!(ret & VM_FAULT_ERROR))
continue;
remainder = 0;
break;
}
+ pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT;
+ page = pte_page(*pte);
+same_page:
if (pages) {
- page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
get_page(page);
- pages[i] = page;
+ pages[i] = page + pfn_offset;
}
if (vmas)
vmas[i] = vma;
vaddr += PAGE_SIZE;
- ++vpfn;
+ ++pfn_offset;
--remainder;
++i;
+ if (vaddr < vma->vm_end && remainder &&
+ pfn_offset < HPAGE_SIZE/PAGE_SIZE) {
+ /*
+ * We use pfn_offset to avoid touching the pageframes
+ * of this compound page.
+ */
+ goto same_page;
+ }
}
spin_unlock(&mm->page_table_lock);
*length = remainder;
return i;
}
+
+void hugetlb_change_protection(struct vm_area_struct *vma,
+ unsigned long address, unsigned long end, pgprot_t newprot)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ unsigned long start = address;
+ pte_t *ptep;
+ pte_t pte;
+
+ BUG_ON(address >= end);
+ flush_cache_range(vma, address, end);
+
+ spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
+ spin_lock(&mm->page_table_lock);
+ for (; address < end; address += HPAGE_SIZE) {
+ ptep = huge_pte_offset(mm, address);
+ if (!ptep)
+ continue;
+ if (huge_pmd_unshare(mm, &address, ptep))
+ continue;
+ if (!pte_none(*ptep)) {
+ pte = huge_ptep_get_and_clear(mm, address, ptep);
+ pte = pte_mkhuge(pte_modify(pte, newprot));
+ set_huge_pte_at(mm, address, ptep, pte);
+ }
+ }
+ spin_unlock(&mm->page_table_lock);
+ spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
+
+ flush_tlb_range(vma, start, end);
+}
+
+struct file_region {
+ struct list_head link;
+ long from;
+ long to;
+};
+
+static long region_add(struct list_head *head, long f, long t)
+{
+ struct file_region *rg, *nrg, *trg;
+
+ /* Locate the region we are either in or before. */
+ list_for_each_entry(rg, head, link)
+ if (f <= rg->to)
+ break;
+
+ /* Round our left edge to the current segment if it encloses us. */
+ if (f > rg->from)
+ f = rg->from;
+
+ /* Check for and consume any regions we now overlap with. */
+ nrg = rg;
+ list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
+ if (&rg->link == head)
+ break;
+ if (rg->from > t)
+ break;
+
+ /* If this area reaches higher then extend our area to
+ * include it completely. If this is not the first area
+ * which we intend to reuse, free it. */
+ if (rg->to > t)
+ t = rg->to;
+ if (rg != nrg) {
+ list_del(&rg->link);
+ kfree(rg);
+ }
+ }
+ nrg->from = f;
+ nrg->to = t;
+ return 0;
+}
+
+static long region_chg(struct list_head *head, long f, long t)
+{
+ struct file_region *rg, *nrg;
+ long chg = 0;
+
+ /* Locate the region we are before or in. */
+ list_for_each_entry(rg, head, link)
+ if (f <= rg->to)
+ break;
+
+ /* If we are below the current region then a new region is required.
+ * Subtle, allocate a new region at the position but make it zero
+ * size such that we can guarantee to record the reservation. */
+ if (&rg->link == head || t < rg->from) {
+ nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
+ if (!nrg)
+ return -ENOMEM;
+ nrg->from = f;
+ nrg->to = f;
+ INIT_LIST_HEAD(&nrg->link);
+ list_add(&nrg->link, rg->link.prev);
+
+ return t - f;
+ }
+
+ /* Round our left edge to the current segment if it encloses us. */
+ if (f > rg->from)
+ f = rg->from;
+ chg = t - f;
+
+ /* Check for and consume any regions we now overlap with. */
+ list_for_each_entry(rg, rg->link.prev, link) {
+ if (&rg->link == head)
+ break;
+ if (rg->from > t)
+ return chg;
+
+ /* We overlap with this area, if it extends futher than
+ * us then we must extend ourselves. Account for its
+ * existing reservation. */
+ if (rg->to > t) {
+ chg += rg->to - t;
+ t = rg->to;
+ }
+ chg -= rg->to - rg->from;
+ }
+ return chg;
+}
+
+static long region_truncate(struct list_head *head, long end)
+{
+ struct file_region *rg, *trg;
+ long chg = 0;
+
+ /* Locate the region we are either in or before. */
+ list_for_each_entry(rg, head, link)
+ if (end <= rg->to)
+ break;
+ if (&rg->link == head)
+ return 0;
+
+ /* If we are in the middle of a region then adjust it. */
+ if (end > rg->from) {
+ chg = rg->to - end;
+ rg->to = end;
+ rg = list_entry(rg->link.next, typeof(*rg), link);
+ }
+
+ /* Drop any remaining regions. */
+ list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
+ if (&rg->link == head)
+ break;
+ chg += rg->to - rg->from;
+ list_del(&rg->link);
+ kfree(rg);
+ }
+ return chg;
+}
+
+static int hugetlb_acct_memory(long delta)
+{
+ int ret = -ENOMEM;
+
+ spin_lock(&hugetlb_lock);
+ /*
+ * When cpuset is configured, it breaks the strict hugetlb page
+ * reservation as the accounting is done on a global variable. Such
+ * reservation is completely rubbish in the presence of cpuset because
+ * the reservation is not checked against page availability for the
+ * current cpuset. Application can still potentially OOM'ed by kernel
+ * with lack of free htlb page in cpuset that the task is in.
+ * Attempt to enforce strict accounting with cpuset is almost
+ * impossible (or too ugly) because cpuset is too fluid that
+ * task or memory node can be dynamically moved between cpusets.
+ *
+ * The change of semantics for shared hugetlb mapping with cpuset is
+ * undesirable. However, in order to preserve some of the semantics,
+ * we fall back to check against current free page availability as
+ * a best attempt and hopefully to minimize the impact of changing
+ * semantics that cpuset has.
+ */
+ if (delta > 0) {
+ if (gather_surplus_pages(delta) < 0)
+ goto out;
+
+ if (delta > cpuset_mems_nr(free_huge_pages_node)) {
+ return_unused_surplus_pages(delta);
+ goto out;
+ }
+ }
+
+ ret = 0;
+ if (delta < 0)
+ return_unused_surplus_pages((unsigned long) -delta);
+
+out:
+ spin_unlock(&hugetlb_lock);
+ return ret;
+}
+
+int hugetlb_reserve_pages(struct inode *inode, long from, long to)
+{
+ long ret, chg;
+
+ chg = region_chg(&inode->i_mapping->private_list, from, to);
+ if (chg < 0)
+ return chg;
+
+ if (hugetlb_get_quota(inode->i_mapping, chg))
+ return -ENOSPC;
+ ret = hugetlb_acct_memory(chg);
+ if (ret < 0) {
+ hugetlb_put_quota(inode->i_mapping, chg);
+ return ret;
+ }
+ region_add(&inode->i_mapping->private_list, from, to);
+ return 0;
+}
+
+void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
+{
+ long chg = region_truncate(&inode->i_mapping->private_list, offset);
+
+ spin_lock(&inode->i_lock);
+ inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed;
+ spin_unlock(&inode->i_lock);
+
+ hugetlb_put_quota(inode->i_mapping, (chg - freed));
+ hugetlb_acct_memory(-(chg - freed));
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff