![Nishanth Aravamudan](/assets/img/avatar_default.png)
When I replaced hugetlb_dynamic_pool with nr_overcommit_hugepages I used proc_doulongvec_minmax() directly. However, hugetlb.c's locking rules require that all counter modifications occur under the hugetlb_lock. Add a callback into the hugetlb code similar to the one for nr_hugepages. Grab the lock around the manipulation of nr_overcommit_hugepages in proc_doulongvec_minmax(). Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Acked-by: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1250 lines
31 KiB
C
1250 lines
31 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 <linux/cpuset.h>
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#include <linux/mutex.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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#include "internal.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, resv_huge_pages;
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static unsigned long surplus_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 unsigned int surplus_huge_pages_node[MAX_NUMNODES];
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static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
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unsigned long hugepages_treat_as_movable;
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unsigned long nr_overcommit_huge_pages;
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static int hugetlb_next_nid;
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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 clear_huge_page(struct page *page, unsigned long addr)
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{
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int i;
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might_sleep();
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for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) {
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cond_resched();
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clear_user_highpage(page + i, addr + i * PAGE_SIZE);
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}
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}
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static void copy_huge_page(struct page *dst, struct page *src,
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unsigned long addr, struct vm_area_struct *vma)
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{
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int i;
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might_sleep();
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for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) {
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cond_resched();
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copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
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}
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}
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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;
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struct page *page = NULL;
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struct mempolicy *mpol;
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struct zonelist *zonelist = huge_zonelist(vma, address,
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htlb_alloc_mask, &mpol);
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struct zone **z;
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for (z = zonelist->zones; *z; z++) {
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nid = zone_to_nid(*z);
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if (cpuset_zone_allowed_softwall(*z, htlb_alloc_mask) &&
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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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if (vma && vma->vm_flags & VM_MAYSHARE)
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resv_huge_pages--;
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break;
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}
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}
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mpol_free(mpol); /* unref if mpol !NULL */
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return page;
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}
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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_to_nid(page)]--;
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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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}
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set_compound_page_dtor(page, NULL);
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set_page_refcounted(page);
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__free_pages(page, HUGETLB_PAGE_ORDER);
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}
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static void free_huge_page(struct page *page)
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{
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int nid = page_to_nid(page);
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struct address_space *mapping;
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mapping = (struct address_space *) page_private(page);
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BUG_ON(page_count(page));
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INIT_LIST_HEAD(&page->lru);
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spin_lock(&hugetlb_lock);
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if (surplus_huge_pages_node[nid]) {
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update_and_free_page(page);
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surplus_huge_pages--;
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surplus_huge_pages_node[nid]--;
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} else {
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enqueue_huge_page(page);
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}
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spin_unlock(&hugetlb_lock);
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if (mapping)
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hugetlb_put_quota(mapping, 1);
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set_page_private(page, 0);
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}
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/*
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* Increment or decrement surplus_huge_pages. Keep node-specific counters
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* balanced by operating on them in a round-robin fashion.
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* Returns 1 if an adjustment was made.
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*/
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static int adjust_pool_surplus(int delta)
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{
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static int prev_nid;
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int nid = prev_nid;
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int ret = 0;
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VM_BUG_ON(delta != -1 && delta != 1);
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do {
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nid = next_node(nid, node_online_map);
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if (nid == MAX_NUMNODES)
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nid = first_node(node_online_map);
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/* To shrink on this node, there must be a surplus page */
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if (delta < 0 && !surplus_huge_pages_node[nid])
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continue;
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/* Surplus cannot exceed the total number of pages */
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if (delta > 0 && surplus_huge_pages_node[nid] >=
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nr_huge_pages_node[nid])
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continue;
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surplus_huge_pages += delta;
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surplus_huge_pages_node[nid] += delta;
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ret = 1;
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break;
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} while (nid != prev_nid);
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prev_nid = nid;
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return ret;
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}
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static struct page *alloc_fresh_huge_page_node(int nid)
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{
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struct page *page;
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page = alloc_pages_node(nid,
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htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN,
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HUGETLB_PAGE_ORDER);
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if (page) {
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set_compound_page_dtor(page, free_huge_page);
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spin_lock(&hugetlb_lock);
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nr_huge_pages++;
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nr_huge_pages_node[nid]++;
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spin_unlock(&hugetlb_lock);
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put_page(page); /* free it into the hugepage allocator */
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}
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return page;
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}
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static int alloc_fresh_huge_page(void)
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{
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struct page *page;
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int start_nid;
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int next_nid;
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int ret = 0;
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start_nid = hugetlb_next_nid;
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do {
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page = alloc_fresh_huge_page_node(hugetlb_next_nid);
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if (page)
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ret = 1;
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/*
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* Use a helper variable to find the next node and then
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* copy it back to hugetlb_next_nid afterwards:
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* otherwise there's a window in which a racer might
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* pass invalid nid MAX_NUMNODES to alloc_pages_node.
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* But we don't need to use a spin_lock here: it really
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* doesn't matter if occasionally a racer chooses the
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* same nid as we do. Move nid forward in the mask even
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* if we just successfully allocated a hugepage so that
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* the next caller gets hugepages on the next node.
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*/
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next_nid = next_node(hugetlb_next_nid, node_online_map);
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if (next_nid == MAX_NUMNODES)
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next_nid = first_node(node_online_map);
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hugetlb_next_nid = next_nid;
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} while (!page && hugetlb_next_nid != start_nid);
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return ret;
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}
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static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma,
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unsigned long address)
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{
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struct page *page;
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unsigned int nid;
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/*
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* Assume we will successfully allocate the surplus page to
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* prevent racing processes from causing the surplus to exceed
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* overcommit
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*
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* This however introduces a different race, where a process B
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* tries to grow the static hugepage pool while alloc_pages() is
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* called by process A. B will only examine the per-node
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* counters in determining if surplus huge pages can be
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* converted to normal huge pages in adjust_pool_surplus(). A
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* won't be able to increment the per-node counter, until the
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* lock is dropped by B, but B doesn't drop hugetlb_lock until
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* no more huge pages can be converted from surplus to normal
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* state (and doesn't try to convert again). Thus, we have a
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* case where a surplus huge page exists, the pool is grown, and
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* the surplus huge page still exists after, even though it
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* should just have been converted to a normal huge page. This
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* does not leak memory, though, as the hugepage will be freed
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* once it is out of use. It also does not allow the counters to
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* go out of whack in adjust_pool_surplus() as we don't modify
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* the node values until we've gotten the hugepage and only the
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* per-node value is checked there.
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*/
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spin_lock(&hugetlb_lock);
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if (surplus_huge_pages >= nr_overcommit_huge_pages) {
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spin_unlock(&hugetlb_lock);
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return NULL;
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} else {
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nr_huge_pages++;
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surplus_huge_pages++;
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}
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spin_unlock(&hugetlb_lock);
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page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN,
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HUGETLB_PAGE_ORDER);
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spin_lock(&hugetlb_lock);
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if (page) {
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nid = page_to_nid(page);
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set_compound_page_dtor(page, free_huge_page);
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/*
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* We incremented the global counters already
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*/
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nr_huge_pages_node[nid]++;
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surplus_huge_pages_node[nid]++;
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} else {
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nr_huge_pages--;
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surplus_huge_pages--;
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}
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spin_unlock(&hugetlb_lock);
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return page;
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}
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/*
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* Increase the hugetlb pool such that it can accomodate a reservation
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* of size 'delta'.
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*/
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static int gather_surplus_pages(int delta)
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{
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struct list_head surplus_list;
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struct page *page, *tmp;
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int ret, i;
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int needed, allocated;
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needed = (resv_huge_pages + delta) - free_huge_pages;
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if (needed <= 0)
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return 0;
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allocated = 0;
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INIT_LIST_HEAD(&surplus_list);
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ret = -ENOMEM;
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retry:
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spin_unlock(&hugetlb_lock);
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for (i = 0; i < needed; i++) {
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page = alloc_buddy_huge_page(NULL, 0);
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if (!page) {
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/*
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* We were not able to allocate enough pages to
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* satisfy the entire reservation so we free what
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* we've allocated so far.
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*/
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spin_lock(&hugetlb_lock);
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needed = 0;
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goto free;
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}
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list_add(&page->lru, &surplus_list);
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}
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allocated += needed;
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/*
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* After retaking hugetlb_lock, we need to recalculate 'needed'
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* because either resv_huge_pages or free_huge_pages may have changed.
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*/
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spin_lock(&hugetlb_lock);
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needed = (resv_huge_pages + delta) - (free_huge_pages + allocated);
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if (needed > 0)
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goto retry;
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/*
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* The surplus_list now contains _at_least_ the number of extra pages
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* needed to accomodate the reservation. Add the appropriate number
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* of pages to the hugetlb pool and free the extras back to the buddy
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* allocator.
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*/
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needed += allocated;
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ret = 0;
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free:
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list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
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list_del(&page->lru);
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if ((--needed) >= 0)
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enqueue_huge_page(page);
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else {
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/*
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* Decrement the refcount and free the page using its
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* destructor. This must be done with hugetlb_lock
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* unlocked which is safe because free_huge_page takes
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* hugetlb_lock before deciding how to free the page.
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*/
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spin_unlock(&hugetlb_lock);
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put_page(page);
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spin_lock(&hugetlb_lock);
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}
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}
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return ret;
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}
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/*
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* When releasing a hugetlb pool reservation, any surplus pages that were
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* allocated to satisfy the reservation must be explicitly freed if they were
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* never used.
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*/
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static void return_unused_surplus_pages(unsigned long unused_resv_pages)
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{
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static int nid = -1;
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struct page *page;
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unsigned long nr_pages;
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nr_pages = min(unused_resv_pages, surplus_huge_pages);
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while (nr_pages) {
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nid = next_node(nid, node_online_map);
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if (nid == MAX_NUMNODES)
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nid = first_node(node_online_map);
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if (!surplus_huge_pages_node[nid])
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continue;
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if (!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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update_and_free_page(page);
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free_huge_pages--;
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free_huge_pages_node[nid]--;
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surplus_huge_pages--;
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surplus_huge_pages_node[nid]--;
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nr_pages--;
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}
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}
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}
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static struct page *alloc_huge_page_shared(struct vm_area_struct *vma,
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unsigned long addr)
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{
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struct page *page;
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spin_lock(&hugetlb_lock);
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page = dequeue_huge_page(vma, addr);
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spin_unlock(&hugetlb_lock);
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return page ? page : ERR_PTR(-VM_FAULT_OOM);
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}
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static struct page *alloc_huge_page_private(struct vm_area_struct *vma,
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unsigned long addr)
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{
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struct page *page = NULL;
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if (hugetlb_get_quota(vma->vm_file->f_mapping, 1))
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return ERR_PTR(-VM_FAULT_SIGBUS);
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spin_lock(&hugetlb_lock);
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if (free_huge_pages > resv_huge_pages)
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page = dequeue_huge_page(vma, addr);
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spin_unlock(&hugetlb_lock);
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if (!page) {
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page = alloc_buddy_huge_page(vma, addr);
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if (!page) {
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hugetlb_put_quota(vma->vm_file->f_mapping, 1);
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return ERR_PTR(-VM_FAULT_OOM);
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}
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}
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return page;
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}
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static struct page *alloc_huge_page(struct vm_area_struct *vma,
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unsigned long addr)
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{
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struct page *page;
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struct address_space *mapping = vma->vm_file->f_mapping;
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if (vma->vm_flags & VM_MAYSHARE)
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page = alloc_huge_page_shared(vma, addr);
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else
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page = alloc_huge_page_private(vma, addr);
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if (!IS_ERR(page)) {
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set_page_refcounted(page);
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set_page_private(page, (unsigned long) mapping);
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}
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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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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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hugetlb_next_nid = first_node(node_online_map);
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for (i = 0; i < max_huge_pages; ++i) {
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if (!alloc_fresh_huge_page())
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break;
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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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static unsigned int cpuset_mems_nr(unsigned int *array)
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{
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int node;
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unsigned int nr = 0;
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for_each_node_mask(node, cpuset_current_mems_allowed)
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nr += array[node];
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return nr;
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}
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|
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#ifdef CONFIG_SYSCTL
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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;
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|
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for (i = 0; i < MAX_NUMNODES; ++i) {
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struct page *page, *next;
|
|
list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
|
|
if (count >= nr_huge_pages)
|
|
return;
|
|
if (PageHighMem(page))
|
|
continue;
|
|
list_del(&page->lru);
|
|
update_and_free_page(page);
|
|
free_huge_pages--;
|
|
free_huge_pages_node[page_to_nid(page)]--;
|
|
}
|
|
}
|
|
}
|
|
#else
|
|
static inline void try_to_free_low(unsigned long count)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
#define persistent_huge_pages (nr_huge_pages - surplus_huge_pages)
|
|
static unsigned long set_max_huge_pages(unsigned long count)
|
|
{
|
|
unsigned long min_count, ret;
|
|
|
|
/*
|
|
* Increase the pool size
|
|
* First take pages out of surplus state. Then make up the
|
|
* remaining difference by allocating fresh huge pages.
|
|
*
|
|
* We might race with alloc_buddy_huge_page() here and be unable
|
|
* to convert a surplus huge page to a normal huge page. That is
|
|
* not critical, though, it just means the overall size of the
|
|
* pool might be one hugepage larger than it needs to be, but
|
|
* within all the constraints specified by the sysctls.
|
|
*/
|
|
spin_lock(&hugetlb_lock);
|
|
while (surplus_huge_pages && count > persistent_huge_pages) {
|
|
if (!adjust_pool_surplus(-1))
|
|
break;
|
|
}
|
|
|
|
while (count > persistent_huge_pages) {
|
|
int ret;
|
|
/*
|
|
* If this allocation races such that we no longer need the
|
|
* page, free_huge_page will handle it by freeing the page
|
|
* and reducing the surplus.
|
|
*/
|
|
spin_unlock(&hugetlb_lock);
|
|
ret = alloc_fresh_huge_page();
|
|
spin_lock(&hugetlb_lock);
|
|
if (!ret)
|
|
goto out;
|
|
|
|
}
|
|
|
|
/*
|
|
* Decrease the pool size
|
|
* First return free pages to the buddy allocator (being careful
|
|
* to keep enough around to satisfy reservations). Then place
|
|
* pages into surplus state as needed so the pool will shrink
|
|
* to the desired size as pages become free.
|
|
*
|
|
* By placing pages into the surplus state independent of the
|
|
* overcommit value, we are allowing the surplus pool size to
|
|
* exceed overcommit. There are few sane options here. Since
|
|
* alloc_buddy_huge_page() is checking the global counter,
|
|
* though, we'll note that we're not allowed to exceed surplus
|
|
* and won't grow the pool anywhere else. Not until one of the
|
|
* sysctls are changed, or the surplus pages go out of use.
|
|
*/
|
|
min_count = resv_huge_pages + nr_huge_pages - free_huge_pages;
|
|
min_count = max(count, min_count);
|
|
try_to_free_low(min_count);
|
|
while (min_count < persistent_huge_pages) {
|
|
struct page *page = dequeue_huge_page(NULL, 0);
|
|
if (!page)
|
|
break;
|
|
update_and_free_page(page);
|
|
}
|
|
while (count < persistent_huge_pages) {
|
|
if (!adjust_pool_surplus(1))
|
|
break;
|
|
}
|
|
out:
|
|
ret = persistent_huge_pages;
|
|
spin_unlock(&hugetlb_lock);
|
|
return ret;
|
|
}
|
|
|
|
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
|
|
struct file *file, void __user *buffer,
|
|
size_t *length, loff_t *ppos)
|
|
{
|
|
proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
|
|
max_huge_pages = set_max_huge_pages(max_huge_pages);
|
|
return 0;
|
|
}
|
|
|
|
int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
|
|
struct file *file, void __user *buffer,
|
|
size_t *length, loff_t *ppos)
|
|
{
|
|
proc_dointvec(table, write, file, buffer, length, ppos);
|
|
if (hugepages_treat_as_movable)
|
|
htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
|
|
else
|
|
htlb_alloc_mask = GFP_HIGHUSER;
|
|
return 0;
|
|
}
|
|
|
|
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
|
|
struct file *file, void __user *buffer,
|
|
size_t *length, loff_t *ppos)
|
|
{
|
|
spin_lock(&hugetlb_lock);
|
|
proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
|
|
spin_unlock(&hugetlb_lock);
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_SYSCTL */
|
|
|
|
int hugetlb_report_meminfo(char *buf)
|
|
{
|
|
return sprintf(buf,
|
|
"HugePages_Total: %5lu\n"
|
|
"HugePages_Free: %5lu\n"
|
|
"HugePages_Rsvd: %5lu\n"
|
|
"HugePages_Surp: %5lu\n"
|
|
"Hugepagesize: %5lu kB\n",
|
|
nr_huge_pages,
|
|
free_huge_pages,
|
|
resv_huge_pages,
|
|
surplus_huge_pages,
|
|
HPAGE_SIZE/1024);
|
|
}
|
|
|
|
int hugetlb_report_node_meminfo(int nid, char *buf)
|
|
{
|
|
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. */
|
|
unsigned long hugetlb_total_pages(void)
|
|
{
|
|
return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
|
|
}
|
|
|
|
/*
|
|
* We cannot handle pagefaults against hugetlb pages at all. They cause
|
|
* handle_mm_fault() to try to instantiate regular-sized pages in the
|
|
* hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
|
|
* this far.
|
|
*/
|
|
static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
{
|
|
BUG();
|
|
return 0;
|
|
}
|
|
|
|
struct vm_operations_struct hugetlb_vm_ops = {
|
|
.fault = hugetlb_vm_op_fault,
|
|
};
|
|
|
|
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));
|
|
if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {
|
|
update_mmu_cache(vma, address, 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;
|
|
|
|
/* If the pagetables are shared don't copy or take references */
|
|
if (dst_pte == src_pte)
|
|
continue;
|
|
|
|
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);
|
|
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 0;
|
|
}
|
|
|
|
page_cache_get(old_page);
|
|
new_page = alloc_huge_page(vma, address);
|
|
|
|
if (IS_ERR(new_page)) {
|
|
page_cache_release(old_page);
|
|
return -PTR_ERR(new_page);
|
|
}
|
|
|
|
spin_unlock(&mm->page_table_lock);
|
|
copy_huge_page(new_page, old_page, address, vma);
|
|
__SetPageUptodate(new_page);
|
|
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 0;
|
|
}
|
|
|
|
static 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;
|
|
page = alloc_huge_page(vma, address);
|
|
if (IS_ERR(page)) {
|
|
ret = -PTR_ERR(page);
|
|
goto out;
|
|
}
|
|
clear_huge_page(page, address);
|
|
__SetPageUptodate(page);
|
|
|
|
if (vma->vm_flags & VM_SHARED) {
|
|
int err;
|
|
struct inode *inode = mapping->host;
|
|
|
|
err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
|
|
if (err) {
|
|
put_page(page);
|
|
if (err == -EEXIST)
|
|
goto retry;
|
|
goto out;
|
|
}
|
|
|
|
spin_lock(&inode->i_lock);
|
|
inode->i_blocks += BLOCKS_PER_HUGEPAGE;
|
|
spin_unlock(&inode->i_lock);
|
|
} else
|
|
lock_page(page);
|
|
}
|
|
|
|
spin_lock(&mm->page_table_lock);
|
|
size = i_size_read(mapping->host) >> HPAGE_SHIFT;
|
|
if (idx >= size)
|
|
goto backout;
|
|
|
|
ret = 0;
|
|
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);
|
|
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 = 0;
|
|
|
|
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,
|
|
int write)
|
|
{
|
|
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) || (write && !pte_write(*pte))) {
|
|
int ret;
|
|
|
|
spin_unlock(&mm->page_table_lock);
|
|
ret = hugetlb_fault(mm, vma, vaddr, write);
|
|
spin_lock(&mm->page_table_lock);
|
|
if (!(ret & VM_FAULT_ERROR))
|
|
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);
|
|
}
|
|
}
|
|
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 guarantee to record the reservation. */
|
|
if (&rg->link == head || t < rg->from) {
|
|
nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
|
|
if (!nrg)
|
|
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);
|
|
/*
|
|
* When cpuset is configured, it breaks the strict hugetlb page
|
|
* reservation as the accounting is done on a global variable. Such
|
|
* reservation is completely rubbish in the presence of cpuset because
|
|
* the reservation is not checked against page availability for the
|
|
* current cpuset. Application can still potentially OOM'ed by kernel
|
|
* with lack of free htlb page in cpuset that the task is in.
|
|
* Attempt to enforce strict accounting with cpuset is almost
|
|
* impossible (or too ugly) because cpuset is too fluid that
|
|
* task or memory node can be dynamically moved between cpusets.
|
|
*
|
|
* The change of semantics for shared hugetlb mapping with cpuset is
|
|
* undesirable. However, in order to preserve some of the semantics,
|
|
* we fall back to check against current free page availability as
|
|
* a best attempt and hopefully to minimize the impact of changing
|
|
* semantics that cpuset has.
|
|
*/
|
|
if (delta > 0) {
|
|
if (gather_surplus_pages(delta) < 0)
|
|
goto out;
|
|
|
|
if (delta > cpuset_mems_nr(free_huge_pages_node))
|
|
goto out;
|
|
}
|
|
|
|
ret = 0;
|
|
resv_huge_pages += delta;
|
|
if (delta < 0)
|
|
return_unused_surplus_pages((unsigned long) -delta);
|
|
|
|
out:
|
|
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;
|
|
|
|
if (hugetlb_get_quota(inode->i_mapping, chg))
|
|
return -ENOSPC;
|
|
ret = hugetlb_acct_memory(chg);
|
|
if (ret < 0) {
|
|
hugetlb_put_quota(inode->i_mapping, chg);
|
|
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);
|
|
|
|
spin_lock(&inode->i_lock);
|
|
inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed;
|
|
spin_unlock(&inode->i_lock);
|
|
|
|
hugetlb_put_quota(inode->i_mapping, (chg - freed));
|
|
hugetlb_acct_memory(-(chg - freed));
|
|
}
|