#include "internal.h"
const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
-static unsigned long nr_huge_pages, free_huge_pages, resv_huge_pages;
+static unsigned long nr_huge_pages, free_huge_pages, reserved_huge_pages;
unsigned long max_huge_pages;
static struct list_head hugepage_freelists[MAX_NUMNODES];
static unsigned int nr_huge_pages_node[MAX_NUMNODES];
static struct page *alloc_huge_page(struct vm_area_struct *vma,
unsigned long addr)
{
+ struct inode *inode = vma->vm_file->f_dentry->d_inode;
struct page *page;
+ int use_reserve = 0;
+ unsigned long idx;
spin_lock(&hugetlb_lock);
- if (vma->vm_flags & VM_MAYSHARE)
- resv_huge_pages--;
- else if (free_huge_pages <= resv_huge_pages)
- goto fail;
+
+ if (vma->vm_flags & VM_MAYSHARE) {
+
+ /* idx = radix tree index, i.e. offset into file in
+ * HPAGE_SIZE units */
+ idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
+ + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
+
+ /* The hugetlbfs specific inode info stores the number
+ * of "guaranteed available" (huge) pages. That is,
+ * the first 'prereserved_hpages' pages of the inode
+ * are either already instantiated, or have been
+ * pre-reserved (by hugetlb_reserve_for_inode()). Here
+ * we're in the process of instantiating the page, so
+ * we use this to determine whether to draw from the
+ * pre-reserved pool or the truly free pool. */
+ if (idx < HUGETLBFS_I(inode)->prereserved_hpages)
+ use_reserve = 1;
+ }
+
+ if (!use_reserve) {
+ if (free_huge_pages <= reserved_huge_pages)
+ goto fail;
+ } else {
+ BUG_ON(reserved_huge_pages == 0);
+ reserved_huge_pages--;
+ }
page = dequeue_huge_page(vma, addr);
if (!page)
set_page_refcounted(page);
return page;
-fail:
+ fail:
+ WARN_ON(use_reserve); /* reserved allocations shouldn't fail */
spin_unlock(&hugetlb_lock);
return NULL;
}
+/* hugetlb_extend_reservation()
+ *
+ * Ensure that at least 'atleast' hugepages are, and will remain,
+ * available to instantiate the first 'atleast' pages of the given
+ * inode. If the inode doesn't already have this many pages reserved
+ * or instantiated, set aside some hugepages in the reserved pool to
+ * satisfy later faults (or fail now if there aren't enough, rather
+ * than getting the SIGBUS later).
+ */
+int hugetlb_extend_reservation(struct hugetlbfs_inode_info *info,
+ unsigned long atleast)
+{
+ struct inode *inode = &info->vfs_inode;
+ unsigned long change_in_reserve = 0;
+ int ret = 0;
+
+ spin_lock(&hugetlb_lock);
+ read_lock_irq(&inode->i_mapping->tree_lock);
+
+ if (info->prereserved_hpages >= atleast)
+ goto out;
+
+ /* Because we always call this on shared mappings, none of the
+ * pages beyond info->prereserved_hpages can have been
+ * instantiated, so we need to reserve all of them now. */
+ change_in_reserve = atleast - info->prereserved_hpages;
+
+ if ((reserved_huge_pages + change_in_reserve) > free_huge_pages) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ reserved_huge_pages += change_in_reserve;
+ info->prereserved_hpages = atleast;
+
+ out:
+ read_unlock_irq(&inode->i_mapping->tree_lock);
+ spin_unlock(&hugetlb_lock);
+
+ return ret;
+}
+
+/* hugetlb_truncate_reservation()
+ *
+ * This returns pages reserved for the given inode to the general free
+ * hugepage pool. If the inode has any pages prereserved, but not
+ * instantiated, beyond offset (atmost << HPAGE_SIZE), then release
+ * them.
+ */
+void hugetlb_truncate_reservation(struct hugetlbfs_inode_info *info,
+ unsigned long atmost)
+{
+ struct inode *inode = &info->vfs_inode;
+ struct address_space *mapping = inode->i_mapping;
+ unsigned long idx;
+ unsigned long change_in_reserve = 0;
+ struct page *page;
+
+ spin_lock(&hugetlb_lock);
+ read_lock_irq(&inode->i_mapping->tree_lock);
+
+ if (info->prereserved_hpages <= atmost)
+ goto out;
+
+ /* Count pages which were reserved, but not instantiated, and
+ * which we can now release. */
+ for (idx = atmost; idx < info->prereserved_hpages; idx++) {
+ page = radix_tree_lookup(&mapping->page_tree, idx);
+ if (!page)
+ /* Pages which are already instantiated can't
+ * be unreserved (and in fact have already
+ * been removed from the reserved pool) */
+ change_in_reserve++;
+ }
+
+ BUG_ON(reserved_huge_pages < change_in_reserve);
+ reserved_huge_pages -= change_in_reserve;
+ info->prereserved_hpages = atmost;
+
+ out:
+ read_unlock_irq(&inode->i_mapping->tree_lock);
+ spin_unlock(&hugetlb_lock);
+}
+
static int __init hugetlb_init(void)
{
unsigned long i;
return nr_huge_pages;
spin_lock(&hugetlb_lock);
- count = max(count, resv_huge_pages);
+ count = max(count, reserved_huge_pages);
try_to_free_low(count);
while (count < nr_huge_pages) {
struct page *page = dequeue_huge_page(NULL, 0);
return sprintf(buf,
"HugePages_Total: %5lu\n"
"HugePages_Free: %5lu\n"
- "HugePages_Rsvd: %5lu\n"
+ "HugePages_Rsvd: %5lu\n"
"Hugepagesize: %5lu kB\n",
nr_huge_pages,
free_huge_pages,
- resv_huge_pages,
+ reserved_huge_pages,
HPAGE_SIZE/1024);
}
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 guarentee to record the reservation. */
- if (&rg->link == head || t < rg->from) {
- nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
- if (nrg == 0)
- 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);
- if ((delta + resv_huge_pages) <= free_huge_pages) {
- resv_huge_pages += delta;
- ret = 0;
- }
- 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;
- ret = hugetlb_acct_memory(chg);
- if (ret < 0)
- 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);
- hugetlb_acct_memory(freed - chg);
-}
git://git.onelab.eu / linux-2.6.git / blobdiff