![Hugh Dickins](/assets/img/avatar_default.png)
This reverts commit 3359b54c8c
and
replaces it with a cleaner version that is purely based on page table
operations, so that the synchronization between inode size and hugetlb
mappings becomes moot.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
472 lines
11 KiB
C
472 lines
11 KiB
C
/*
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* Generic hugetlb support.
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* (C) William Irwin, April 2004
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*/
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#include <linux/gfp.h>
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#include <linux/list.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/sysctl.h>
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#include <linux/highmem.h>
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#include <linux/nodemask.h>
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#include <linux/pagemap.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <linux/hugetlb.h>
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const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
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static unsigned long nr_huge_pages, free_huge_pages;
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unsigned long max_huge_pages;
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static struct list_head hugepage_freelists[MAX_NUMNODES];
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static unsigned int nr_huge_pages_node[MAX_NUMNODES];
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static unsigned int free_huge_pages_node[MAX_NUMNODES];
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static DEFINE_SPINLOCK(hugetlb_lock);
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static void enqueue_huge_page(struct page *page)
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{
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int nid = page_to_nid(page);
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list_add(&page->lru, &hugepage_freelists[nid]);
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free_huge_pages++;
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free_huge_pages_node[nid]++;
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}
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static struct page *dequeue_huge_page(void)
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{
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int nid = numa_node_id();
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struct page *page = NULL;
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if (list_empty(&hugepage_freelists[nid])) {
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for (nid = 0; nid < MAX_NUMNODES; ++nid)
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if (!list_empty(&hugepage_freelists[nid]))
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break;
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}
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if (nid >= 0 && nid < MAX_NUMNODES &&
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!list_empty(&hugepage_freelists[nid])) {
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page = list_entry(hugepage_freelists[nid].next,
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struct page, lru);
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list_del(&page->lru);
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free_huge_pages--;
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free_huge_pages_node[nid]--;
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}
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return page;
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}
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static struct page *alloc_fresh_huge_page(void)
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{
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static int nid = 0;
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struct page *page;
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page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
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HUGETLB_PAGE_ORDER);
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nid = (nid + 1) % num_online_nodes();
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if (page) {
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nr_huge_pages++;
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nr_huge_pages_node[page_to_nid(page)]++;
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}
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return page;
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}
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void free_huge_page(struct page *page)
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{
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BUG_ON(page_count(page));
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INIT_LIST_HEAD(&page->lru);
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page[1].mapping = NULL;
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spin_lock(&hugetlb_lock);
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enqueue_huge_page(page);
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spin_unlock(&hugetlb_lock);
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}
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struct page *alloc_huge_page(void)
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{
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struct page *page;
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int i;
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spin_lock(&hugetlb_lock);
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page = dequeue_huge_page();
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if (!page) {
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spin_unlock(&hugetlb_lock);
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return NULL;
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}
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spin_unlock(&hugetlb_lock);
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set_page_count(page, 1);
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page[1].mapping = (void *)free_huge_page;
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for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i)
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clear_highpage(&page[i]);
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return page;
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}
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static int __init hugetlb_init(void)
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{
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unsigned long i;
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struct page *page;
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for (i = 0; i < MAX_NUMNODES; ++i)
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INIT_LIST_HEAD(&hugepage_freelists[i]);
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for (i = 0; i < max_huge_pages; ++i) {
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page = alloc_fresh_huge_page();
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if (!page)
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break;
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spin_lock(&hugetlb_lock);
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enqueue_huge_page(page);
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spin_unlock(&hugetlb_lock);
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}
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max_huge_pages = free_huge_pages = nr_huge_pages = i;
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printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
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return 0;
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}
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module_init(hugetlb_init);
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static int __init hugetlb_setup(char *s)
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{
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if (sscanf(s, "%lu", &max_huge_pages) <= 0)
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max_huge_pages = 0;
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return 1;
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}
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__setup("hugepages=", hugetlb_setup);
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#ifdef CONFIG_SYSCTL
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static void update_and_free_page(struct page *page)
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{
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int i;
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nr_huge_pages--;
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nr_huge_pages_node[page_zone(page)->zone_pgdat->node_id]--;
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for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
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page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
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1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
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1 << PG_private | 1<< PG_writeback);
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set_page_count(&page[i], 0);
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}
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set_page_count(page, 1);
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__free_pages(page, HUGETLB_PAGE_ORDER);
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}
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#ifdef CONFIG_HIGHMEM
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static void try_to_free_low(unsigned long count)
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{
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int i, nid;
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for (i = 0; i < MAX_NUMNODES; ++i) {
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struct page *page, *next;
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list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
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if (PageHighMem(page))
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continue;
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list_del(&page->lru);
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update_and_free_page(page);
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nid = page_zone(page)->zone_pgdat->node_id;
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free_huge_pages--;
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free_huge_pages_node[nid]--;
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if (count >= nr_huge_pages)
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return;
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}
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}
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}
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#else
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static inline void try_to_free_low(unsigned long count)
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{
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}
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#endif
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static unsigned long set_max_huge_pages(unsigned long count)
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{
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while (count > nr_huge_pages) {
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struct page *page = alloc_fresh_huge_page();
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if (!page)
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return nr_huge_pages;
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spin_lock(&hugetlb_lock);
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enqueue_huge_page(page);
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spin_unlock(&hugetlb_lock);
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}
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if (count >= nr_huge_pages)
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return nr_huge_pages;
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spin_lock(&hugetlb_lock);
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try_to_free_low(count);
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while (count < nr_huge_pages) {
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struct page *page = dequeue_huge_page();
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if (!page)
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break;
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update_and_free_page(page);
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}
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spin_unlock(&hugetlb_lock);
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return nr_huge_pages;
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}
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int hugetlb_sysctl_handler(struct ctl_table *table, int write,
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struct file *file, void __user *buffer,
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size_t *length, loff_t *ppos)
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{
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proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
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max_huge_pages = set_max_huge_pages(max_huge_pages);
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return 0;
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}
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#endif /* CONFIG_SYSCTL */
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int hugetlb_report_meminfo(char *buf)
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{
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return sprintf(buf,
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"HugePages_Total: %5lu\n"
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"HugePages_Free: %5lu\n"
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"Hugepagesize: %5lu kB\n",
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nr_huge_pages,
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free_huge_pages,
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HPAGE_SIZE/1024);
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}
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int hugetlb_report_node_meminfo(int nid, char *buf)
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{
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return sprintf(buf,
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"Node %d HugePages_Total: %5u\n"
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"Node %d HugePages_Free: %5u\n",
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nid, nr_huge_pages_node[nid],
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nid, free_huge_pages_node[nid]);
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}
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int is_hugepage_mem_enough(size_t size)
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{
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return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages;
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}
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/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
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unsigned long hugetlb_total_pages(void)
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{
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return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
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}
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EXPORT_SYMBOL(hugetlb_total_pages);
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/*
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* We cannot handle pagefaults against hugetlb pages at all. They cause
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* handle_mm_fault() to try to instantiate regular-sized pages in the
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* hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
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* this far.
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*/
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static struct page *hugetlb_nopage(struct vm_area_struct *vma,
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unsigned long address, int *unused)
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{
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BUG();
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return NULL;
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}
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struct vm_operations_struct hugetlb_vm_ops = {
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.nopage = hugetlb_nopage,
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};
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static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page)
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{
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pte_t entry;
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if (vma->vm_flags & VM_WRITE) {
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entry =
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pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
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} else {
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entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
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}
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entry = pte_mkyoung(entry);
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entry = pte_mkhuge(entry);
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return entry;
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}
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int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
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struct vm_area_struct *vma)
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{
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pte_t *src_pte, *dst_pte, entry;
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struct page *ptepage;
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unsigned long addr;
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for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
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dst_pte = huge_pte_alloc(dst, addr);
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if (!dst_pte)
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goto nomem;
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spin_lock(&src->page_table_lock);
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src_pte = huge_pte_offset(src, addr);
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if (src_pte && !pte_none(*src_pte)) {
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entry = *src_pte;
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ptepage = pte_page(entry);
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get_page(ptepage);
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add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
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set_huge_pte_at(dst, addr, dst_pte, entry);
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}
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spin_unlock(&src->page_table_lock);
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}
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return 0;
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nomem:
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return -ENOMEM;
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}
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void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
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unsigned long end)
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{
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struct mm_struct *mm = vma->vm_mm;
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unsigned long address;
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pte_t *ptep;
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pte_t pte;
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struct page *page;
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WARN_ON(!is_vm_hugetlb_page(vma));
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BUG_ON(start & ~HPAGE_MASK);
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BUG_ON(end & ~HPAGE_MASK);
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for (address = start; address < end; address += HPAGE_SIZE) {
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ptep = huge_pte_offset(mm, address);
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if (! ptep)
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/* This can happen on truncate, or if an
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* mmap() is aborted due to an error before
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* the prefault */
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continue;
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pte = huge_ptep_get_and_clear(mm, address, ptep);
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if (pte_none(pte))
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continue;
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page = pte_page(pte);
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put_page(page);
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add_mm_counter(mm, rss, - (HPAGE_SIZE / PAGE_SIZE));
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}
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flush_tlb_range(vma, start, end);
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}
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void zap_hugepage_range(struct vm_area_struct *vma,
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unsigned long start, unsigned long length)
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{
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struct mm_struct *mm = vma->vm_mm;
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spin_lock(&mm->page_table_lock);
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unmap_hugepage_range(vma, start, start + length);
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spin_unlock(&mm->page_table_lock);
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}
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int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
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{
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struct mm_struct *mm = current->mm;
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unsigned long addr;
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int ret = 0;
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WARN_ON(!is_vm_hugetlb_page(vma));
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BUG_ON(vma->vm_start & ~HPAGE_MASK);
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BUG_ON(vma->vm_end & ~HPAGE_MASK);
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hugetlb_prefault_arch_hook(mm);
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spin_lock(&mm->page_table_lock);
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for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
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unsigned long idx;
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pte_t *pte = huge_pte_alloc(mm, addr);
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struct page *page;
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if (!pte) {
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ret = -ENOMEM;
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goto out;
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}
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idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
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+ (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
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page = find_get_page(mapping, idx);
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if (!page) {
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/* charge the fs quota first */
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if (hugetlb_get_quota(mapping)) {
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ret = -ENOMEM;
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goto out;
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}
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page = alloc_huge_page();
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if (!page) {
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hugetlb_put_quota(mapping);
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ret = -ENOMEM;
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goto out;
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}
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ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
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if (! ret) {
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unlock_page(page);
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} else {
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hugetlb_put_quota(mapping);
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free_huge_page(page);
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goto out;
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}
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}
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add_mm_counter(mm, rss, HPAGE_SIZE / PAGE_SIZE);
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set_huge_pte_at(mm, addr, pte, make_huge_pte(vma, page));
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}
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out:
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spin_unlock(&mm->page_table_lock);
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return ret;
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}
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/*
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* On ia64 at least, it is possible to receive a hugetlb fault from a
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* stale zero entry left in the TLB from earlier hardware prefetching.
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* Low-level arch code should already have flushed the stale entry as
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* part of its fault handling, but we do need to accept this minor fault
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* and return successfully. Whereas the "normal" case is that this is
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* an access to a hugetlb page which has been truncated off since mmap.
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*/
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int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
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unsigned long address, int write_access)
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{
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int ret = VM_FAULT_SIGBUS;
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pte_t *pte;
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spin_lock(&mm->page_table_lock);
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pte = huge_pte_offset(mm, address);
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if (pte && !pte_none(*pte))
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ret = VM_FAULT_MINOR;
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spin_unlock(&mm->page_table_lock);
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return ret;
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}
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int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
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struct page **pages, struct vm_area_struct **vmas,
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unsigned long *position, int *length, int i)
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{
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unsigned long vpfn, vaddr = *position;
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int remainder = *length;
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BUG_ON(!is_vm_hugetlb_page(vma));
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vpfn = vaddr/PAGE_SIZE;
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spin_lock(&mm->page_table_lock);
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while (vaddr < vma->vm_end && remainder) {
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if (pages) {
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pte_t *pte;
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struct page *page;
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/* Some archs (sparc64, sh*) have multiple
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* pte_ts to each hugepage. We have to make
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* sure we get the first, for the page
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* indexing below to work. */
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pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
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/* the hugetlb file might have been truncated */
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if (!pte || pte_none(*pte)) {
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remainder = 0;
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if (!i)
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i = -EFAULT;
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break;
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}
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page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
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WARN_ON(!PageCompound(page));
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get_page(page);
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pages[i] = page;
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}
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if (vmas)
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vmas[i] = vma;
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vaddr += PAGE_SIZE;
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++vpfn;
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--remainder;
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++i;
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}
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spin_unlock(&mm->page_table_lock);
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*length = remainder;
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*position = vaddr;
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return i;
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}
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