![Christoph Lameter](/assets/img/avatar_default.png)
The number of parameters for find_or_alloc_page increases significantly after policy support is added to huge pages. Simplify the code by folding find_or_alloc_huge_page() into hugetlb_no_page(). Adam Litke objected to this piece in an earlier patch but I think this is a good simplification. Diffstat shows that we can get rid of almost half of the lines of find_or_alloc_page(). If we can find no consensus then lets simply drop this patch. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@muc.de> Acked-by: William Lee Irwin III <wli@holomorphy.com> Cc: Adam Litke <agl@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
577 lines
13 KiB
C
577 lines
13 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 <linux/mempolicy.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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/*
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* Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
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*/
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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(struct vm_area_struct *vma,
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unsigned long address)
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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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struct zonelist *zonelist = huge_zonelist(vma, address);
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struct zone **z;
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for (z = zonelist->zones; *z; z++) {
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nid = (*z)->zone_pgdat->node_id;
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if (!list_empty(&hugepage_freelists[nid]))
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break;
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}
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if (*z) {
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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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spin_lock(&hugetlb_lock);
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nr_huge_pages++;
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nr_huge_pages_node[page_to_nid(page)]++;
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spin_unlock(&hugetlb_lock);
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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(struct vm_area_struct *vma, unsigned long addr)
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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(vma, addr);
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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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if (HPAGE_SHIFT == 0)
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return 0;
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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(NULL, 0);
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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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/*
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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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int writable)
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{
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pte_t entry;
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if (writable) {
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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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static void set_huge_ptep_writable(struct vm_area_struct *vma,
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unsigned long address, pte_t *ptep)
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{
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pte_t entry;
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entry = pte_mkwrite(pte_mkdirty(*ptep));
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ptep_set_access_flags(vma, address, ptep, entry, 1);
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update_mmu_cache(vma, address, entry);
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lazy_mmu_prot_update(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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int cow;
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cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
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for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
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src_pte = huge_pte_offset(src, addr);
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if (!src_pte)
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continue;
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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(&dst->page_table_lock);
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spin_lock(&src->page_table_lock);
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if (!pte_none(*src_pte)) {
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if (cow)
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ptep_set_wrprotect(src, addr, 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, file_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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spin_unlock(&dst->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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spin_lock(&mm->page_table_lock);
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/* Update high watermark before we lower rss */
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update_hiwater_rss(mm);
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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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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, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE));
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}
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spin_unlock(&mm->page_table_lock);
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flush_tlb_range(vma, start, end);
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}
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static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
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unsigned long address, pte_t *ptep, pte_t pte)
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{
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struct page *old_page, *new_page;
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int i, avoidcopy;
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old_page = pte_page(pte);
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/* If no-one else is actually using this page, avoid the copy
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* and just make the page writable */
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avoidcopy = (page_count(old_page) == 1);
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if (avoidcopy) {
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set_huge_ptep_writable(vma, address, ptep);
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return VM_FAULT_MINOR;
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}
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page_cache_get(old_page);
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new_page = alloc_huge_page(vma, address);
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if (!new_page) {
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page_cache_release(old_page);
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/* Logically this is OOM, not a SIGBUS, but an OOM
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* could cause the kernel to go killing other
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* processes which won't help the hugepage situation
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* at all (?) */
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return VM_FAULT_SIGBUS;
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}
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spin_unlock(&mm->page_table_lock);
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for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++)
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copy_user_highpage(new_page + i, old_page + i,
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address + i*PAGE_SIZE);
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spin_lock(&mm->page_table_lock);
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ptep = huge_pte_offset(mm, address & HPAGE_MASK);
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if (likely(pte_same(*ptep, pte))) {
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/* Break COW */
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set_huge_pte_at(mm, address, ptep,
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make_huge_pte(vma, new_page, 1));
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/* Make the old page be freed below */
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new_page = old_page;
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}
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page_cache_release(new_page);
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page_cache_release(old_page);
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return VM_FAULT_MINOR;
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}
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int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
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unsigned long address, pte_t *ptep, int write_access)
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{
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int ret = VM_FAULT_SIGBUS;
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unsigned long idx;
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unsigned long size;
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struct page *page;
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struct address_space *mapping;
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pte_t new_pte;
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mapping = vma->vm_file->f_mapping;
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idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
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+ (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
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/*
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* Use page lock to guard against racing truncation
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* before we get page_table_lock.
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*/
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retry:
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page = find_lock_page(mapping, idx);
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if (!page) {
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if (hugetlb_get_quota(mapping))
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goto out;
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page = alloc_huge_page(vma, address);
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if (!page) {
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hugetlb_put_quota(mapping);
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goto out;
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}
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if (vma->vm_flags & VM_SHARED) {
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int err;
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err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
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if (err) {
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put_page(page);
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hugetlb_put_quota(mapping);
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if (err == -EEXIST)
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goto retry;
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goto out;
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}
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} else
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lock_page(page);
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}
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spin_lock(&mm->page_table_lock);
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size = i_size_read(mapping->host) >> HPAGE_SHIFT;
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if (idx >= size)
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goto backout;
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ret = VM_FAULT_MINOR;
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if (!pte_none(*ptep))
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goto backout;
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add_mm_counter(mm, file_rss, HPAGE_SIZE / PAGE_SIZE);
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new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
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&& (vma->vm_flags & VM_SHARED)));
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set_huge_pte_at(mm, address, ptep, new_pte);
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if (write_access && !(vma->vm_flags & VM_SHARED)) {
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/* Optimization, do the COW without a second fault */
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ret = hugetlb_cow(mm, vma, address, ptep, new_pte);
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}
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spin_unlock(&mm->page_table_lock);
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unlock_page(page);
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out:
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return ret;
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backout:
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spin_unlock(&mm->page_table_lock);
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hugetlb_put_quota(mapping);
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unlock_page(page);
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put_page(page);
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goto out;
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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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{
|
|
pte_t *ptep;
|
|
pte_t entry;
|
|
int ret;
|
|
|
|
ptep = huge_pte_alloc(mm, address);
|
|
if (!ptep)
|
|
return VM_FAULT_OOM;
|
|
|
|
entry = *ptep;
|
|
if (pte_none(entry))
|
|
return hugetlb_no_page(mm, vma, address, ptep, write_access);
|
|
|
|
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);
|
|
|
|
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 vpfn, vaddr = *position;
|
|
int remainder = *length;
|
|
|
|
vpfn = vaddr/PAGE_SIZE;
|
|
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;
|
|
}
|
|
|
|
if (pages) {
|
|
page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
|
|
get_page(page);
|
|
pages[i] = page;
|
|
}
|
|
|
|
if (vmas)
|
|
vmas[i] = vma;
|
|
|
|
vaddr += PAGE_SIZE;
|
|
++vpfn;
|
|
--remainder;
|
|
++i;
|
|
}
|
|
spin_unlock(&mm->page_table_lock);
|
|
*length = remainder;
|
|
*position = vaddr;
|
|
|
|
return i;
|
|
}
|