#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
-#include <linux/hugetlb.h>
#include <linux/sysctl.h>
#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 <linux/vs_memory.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;
unsigned long max_huge_pages;
static struct list_head hugepage_freelists[MAX_NUMNODES];
-static spinlock_t hugetlb_lock = SPIN_LOCK_UNLOCKED;
+static unsigned int nr_huge_pages_node[MAX_NUMNODES];
+static unsigned int free_huge_pages_node[MAX_NUMNODES];
+/*
+ * 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);
+ }
+}
+
+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)
{
- list_add(&page->lru,
- &hugepage_freelists[page_zone(page)->zone_pgdat->node_id]);
+ int nid = page_to_nid(page);
+ list_add(&page->lru, &hugepage_freelists[nid]);
+ free_huge_pages++;
+ free_huge_pages_node[nid]++;
}
-static struct page *dequeue_huge_page(void)
+static struct page *dequeue_huge_page(struct vm_area_struct *vma,
+ unsigned long address)
{
int nid = numa_node_id();
struct page *page = NULL;
+ struct zonelist *zonelist = huge_zonelist(vma, address);
+ struct zone **z;
- if (list_empty(&hugepage_freelists[nid])) {
- for (nid = 0; nid < MAX_NUMNODES; ++nid)
- if (!list_empty(&hugepage_freelists[nid]))
- break;
+ for (z = zonelist->zones; *z; z++) {
+ nid = zone_to_nid(*z);
+ if (cpuset_zone_allowed_softwall(*z, GFP_HIGHUSER) &&
+ !list_empty(&hugepage_freelists[nid]))
+ break;
}
- if (nid >= 0 && nid < MAX_NUMNODES &&
- !list_empty(&hugepage_freelists[nid])) {
+
+ if (*z) {
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 *alloc_fresh_huge_page(void)
-{
- static int nid = 0;
- struct page *page;
- page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP,
- HUGETLB_PAGE_ORDER);
- nid = (nid + 1) % numnodes;
- return page;
-}
-
-void free_huge_page(struct page *page)
+static void free_huge_page(struct page *page)
{
BUG_ON(page_count(page));
INIT_LIST_HEAD(&page->lru);
- page[1].mapping = NULL;
spin_lock(&hugetlb_lock);
enqueue_huge_page(page);
- free_huge_pages++;
spin_unlock(&hugetlb_lock);
}
-struct page *alloc_huge_page(void)
+static int alloc_fresh_huge_page(void)
{
+ static int nid = 0;
struct page *page;
- int i;
-
- spin_lock(&hugetlb_lock);
- page = dequeue_huge_page();
- if (!page) {
+ page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
+ HUGETLB_PAGE_ORDER);
+ nid = next_node(nid, node_online_map);
+ if (nid == MAX_NUMNODES)
+ nid = first_node(node_online_map);
+ 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)]++;
spin_unlock(&hugetlb_lock);
- return NULL;
+ put_page(page); /* free it into the hugepage allocator */
+ return 1;
}
- free_huge_pages--;
+ return 0;
+}
+
+static struct page *alloc_huge_page(struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ struct page *page;
+
+ spin_lock(&hugetlb_lock);
+ 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)
+ goto fail;
+
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]);
+ set_page_refcounted(page);
return page;
+
+fail:
+ spin_unlock(&hugetlb_lock);
+ return NULL;
}
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]);
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)
{
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_page_count(&page[i], 0);
}
- set_page_count(page, 1);
+ page[1].lru.next = NULL;
+ set_page_refcounted(page);
__free_pages(page, HUGETLB_PAGE_ORDER);
}
#ifdef CONFIG_HIGHMEM
-static int try_to_free_low(unsigned long count)
+static void try_to_free_low(unsigned long count)
{
int i;
+
for (i = 0; i < MAX_NUMNODES; ++i) {
- struct page *page;
- list_for_each_entry(page, &hugepage_freelists[i], lru) {
+ struct page *page, *next;
+ list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
if (PageHighMem(page))
continue;
list_del(&page->lru);
update_and_free_page(page);
- --free_huge_pages;
- if (!--count)
- return 0;
+ free_huge_pages--;
+ free_huge_pages_node[page_to_nid(page)]--;
+ if (count >= nr_huge_pages)
+ return;
}
}
- return count;
}
#else
-static inline int try_to_free_low(unsigned long count)
+static inline void try_to_free_low(unsigned long count)
{
- return count;
}
#endif
static unsigned long set_max_huge_pages(unsigned long count)
{
while (count > nr_huge_pages) {
- struct page *page = alloc_fresh_huge_page();
- if (!page)
+ if (!alloc_fresh_huge_page())
return nr_huge_pages;
- spin_lock(&hugetlb_lock);
- enqueue_huge_page(page);
- free_huge_pages++;
- nr_huge_pages++;
- spin_unlock(&hugetlb_lock);
}
if (count >= nr_huge_pages)
return nr_huge_pages;
spin_lock(&hugetlb_lock);
- for (count = try_to_free_low(count); count < nr_huge_pages; --free_huge_pages) {
- struct page *page = dequeue_huge_page();
+ count = max(count, resv_huge_pages);
+ try_to_free_low(count);
+ while (count < nr_huge_pages) {
+ struct page *page = dequeue_huge_page(NULL, 0);
if (!page)
break;
update_and_free_page(page);
return nr_huge_pages;
}
-#ifdef CONFIG_SYSCTL
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
struct file *file, void __user *buffer,
- size_t *length)
+ size_t *length, loff_t *ppos)
{
- proc_doulongvec_minmax(table, write, file, buffer, length);
+ proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
max_huge_pages = set_max_huge_pages(max_huge_pages);
return 0;
}
return sprintf(buf,
"HugePages_Total: %5lu\n"
"HugePages_Free: %5lu\n"
+ "HugePages_Rsvd: %5lu\n"
"Hugepagesize: %5lu kB\n",
nr_huge_pages,
free_huge_pages,
+ resv_huge_pages,
HPAGE_SIZE/1024);
}
-int is_hugepage_mem_enough(size_t size)
+int hugetlb_report_node_meminfo(int nid, char *buf)
{
- return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages;
+ return sprintf(buf,
+ "Node %d HugePages_Total: %5u\n"
+ "Node %d HugePages_Free: %5u\n",
+ nid, nr_huge_pages_node[nid],
+ nid, free_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
.nopage = hugetlb_nopage,
};
-void zap_hugepage_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long length)
+static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
+ int writable)
+{
+ pte_t entry;
+
+ if (writable) {
+ entry =
+ pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
+ } else {
+ entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
+ }
+ entry = pte_mkyoung(entry);
+ entry = pte_mkhuge(entry);
+
+ 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));
+ ptep_set_access_flags(vma, address, ptep, entry, 1);
+ update_mmu_cache(vma, address, entry);
+ lazy_mmu_prot_update(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);
+ if (!src_pte)
+ continue;
+ dst_pte = huge_pte_alloc(dst, addr);
+ if (!dst_pte)
+ goto nomem;
+ 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);
+ set_huge_pte_at(dst, addr, dst_pte, entry);
+ }
+ spin_unlock(&src->page_table_lock);
+ spin_unlock(&dst->page_table_lock);
+ }
+ return 0;
+
+nomem:
+ return -ENOMEM;
+}
+
+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);
- unmap_hugepage_range(vma, start, start + length);
+ 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);
+ 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);
+ }
+}
+
+void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end)
+{
+ /*
+ * 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);
+ }
+}
+
+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;
+
+ old_page = pte_page(pte);
+
+ /* 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 VM_FAULT_MINOR;
+ }
+
+ page_cache_get(old_page);
+ new_page = alloc_huge_page(vma, address);
+
+ if (!new_page) {
+ page_cache_release(old_page);
+ return VM_FAULT_OOM;
+ }
+
spin_unlock(&mm->page_table_lock);
+ copy_huge_page(new_page, old_page, address, vma);
+ 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 VM_FAULT_MINOR;
+}
+
+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;
+ struct page *page;
+ struct address_space *mapping;
+ pte_t new_pte;
+
+ mapping = vma->vm_file->f_mapping;
+ idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
+ + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
+
+ /*
+ * Use page lock to guard against racing truncation
+ * before we get page_table_lock.
+ */
+retry:
+ page = find_lock_page(mapping, idx);
+ if (!page) {
+ size = i_size_read(mapping->host) >> HPAGE_SHIFT;
+ if (idx >= size)
+ goto out;
+ if (hugetlb_get_quota(mapping))
+ goto out;
+ page = alloc_huge_page(vma, address);
+ if (!page) {
+ hugetlb_put_quota(mapping);
+ ret = VM_FAULT_OOM;
+ goto out;
+ }
+ clear_huge_page(page, address);
+
+ if (vma->vm_flags & VM_SHARED) {
+ int err;
+
+ err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
+ if (err) {
+ put_page(page);
+ hugetlb_put_quota(mapping);
+ if (err == -EEXIST)
+ goto retry;
+ goto out;
+ }
+ } 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(*ptep))
+ goto backout;
+
+ 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:
+ return ret;
+
+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 = VM_FAULT_MINOR;
+
+ 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 pfn_offset;
+ unsigned long vaddr = *position;
+ int remainder = *length;
+
+ spin_lock(&mm->page_table_lock);
+ while (vaddr < vma->vm_end && remainder) {
+ pte_t *pte;
+ struct page *page;
+
+ /*
+ * Some archs (sparc64, sh*) have multiple pte_ts to
+ * each hugepage. We have to make * sure we get the
+ * first, for the page indexing below to work.
+ */
+ pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
+
+ if (!pte || pte_none(*pte)) {
+ int ret;
+
+ spin_unlock(&mm->page_table_lock);
+ ret = hugetlb_fault(mm, vma, vaddr, 0);
+ spin_lock(&mm->page_table_lock);
+ if (ret == VM_FAULT_MINOR)
+ continue;
+
+ remainder = 0;
+ if (!i)
+ i = -EFAULT;
+ break;
+ }
+
+ pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT;
+ page = pte_page(*pte);
+same_page:
+ if (pages) {
+ get_page(page);
+ pages[i] = page + pfn_offset;
+ }
+
+ if (vmas)
+ vmas[i] = vma;
+
+ vaddr += PAGE_SIZE;
+ ++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;
+ *position = vaddr;
+
+ 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);
+ lazy_mmu_prot_update(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 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