#include "internal.h"
const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
-static unsigned long nr_huge_pages, free_huge_pages, reserved_huge_pages;
+static unsigned long nr_huge_pages, free_huge_pages, resv_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) {
-
- /* 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--;
- }
+ if (vma->vm_flags & VM_MAYSHARE)
+ resv_huge_pages--;
+ else if (free_huge_pages <= resv_huge_pages)
+ goto fail;
page = dequeue_huge_page(vma, addr);
if (!page)
set_page_refcounted(page);
return page;
- fail:
- WARN_ON(use_reserve); /* reserved allocations shouldn't fail */
+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, reserved_huge_pages);
+ count = max(count, resv_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,
- reserved_huge_pages,
+ resv_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