![KAMEZAWA Hiroyuki](/assets/img/avatar_default.png)
While using memory control cgroup, page-migration under it works as following. == 1. uncharge all refs at try to unmap. 2. charge regs again remove_migration_ptes() == This is simple but has following problems. == The page is uncharged and charged back again if *mapped*. - This means that cgroup before migration can be different from one after migration - If page is not mapped but charged as page cache, charge is just ignored (because not mapped, it will not be uncharged before migration) This is memory leak. == This patch tries to keep memory cgroup at page migration by increasing one refcnt during it. 3 functions are added. mem_cgroup_prepare_migration() --- increase refcnt of page->page_cgroup mem_cgroup_end_migration() --- decrease refcnt of page->page_cgroup mem_cgroup_page_migration() --- copy page->page_cgroup from old page to new page. During migration - old page is under PG_locked. - new page is under PG_locked, too. - both old page and new page is not on LRU. These 3 facts guarantee that page_cgroup() migration has no race. Tested and worked well in x86_64/fake-NUMA box. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Kirill Korotaev <dev@sw.ru> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: David Rientjes <rientjes@google.com> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1069 lines
24 KiB
C
1069 lines
24 KiB
C
/*
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* Memory Migration functionality - linux/mm/migration.c
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*
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* Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter
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*
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* Page migration was first developed in the context of the memory hotplug
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* project. The main authors of the migration code are:
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*
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* IWAMOTO Toshihiro <iwamoto@valinux.co.jp>
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* Hirokazu Takahashi <taka@valinux.co.jp>
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* Dave Hansen <haveblue@us.ibm.com>
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* Christoph Lameter <clameter@sgi.com>
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*/
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#include <linux/migrate.h>
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#include <linux/module.h>
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#include <linux/swap.h>
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#include <linux/swapops.h>
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#include <linux/pagemap.h>
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#include <linux/buffer_head.h>
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#include <linux/mm_inline.h>
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#include <linux/nsproxy.h>
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#include <linux/pagevec.h>
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#include <linux/rmap.h>
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#include <linux/topology.h>
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#include <linux/cpu.h>
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#include <linux/cpuset.h>
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#include <linux/writeback.h>
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#include <linux/mempolicy.h>
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#include <linux/vmalloc.h>
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#include <linux/security.h>
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#include <linux/memcontrol.h>
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#include "internal.h"
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#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
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/*
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* Isolate one page from the LRU lists. If successful put it onto
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* the indicated list with elevated page count.
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*
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* Result:
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* -EBUSY: page not on LRU list
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* 0: page removed from LRU list and added to the specified list.
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*/
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int isolate_lru_page(struct page *page, struct list_head *pagelist)
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{
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int ret = -EBUSY;
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if (PageLRU(page)) {
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struct zone *zone = page_zone(page);
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spin_lock_irq(&zone->lru_lock);
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if (PageLRU(page) && get_page_unless_zero(page)) {
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ret = 0;
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ClearPageLRU(page);
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if (PageActive(page))
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del_page_from_active_list(zone, page);
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else
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del_page_from_inactive_list(zone, page);
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list_add_tail(&page->lru, pagelist);
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}
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spin_unlock_irq(&zone->lru_lock);
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}
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return ret;
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}
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/*
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* migrate_prep() needs to be called before we start compiling a list of pages
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* to be migrated using isolate_lru_page().
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*/
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int migrate_prep(void)
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{
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/*
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* Clear the LRU lists so pages can be isolated.
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* Note that pages may be moved off the LRU after we have
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* drained them. Those pages will fail to migrate like other
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* pages that may be busy.
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*/
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lru_add_drain_all();
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return 0;
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}
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static inline void move_to_lru(struct page *page)
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{
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if (PageActive(page)) {
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/*
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* lru_cache_add_active checks that
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* the PG_active bit is off.
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*/
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ClearPageActive(page);
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lru_cache_add_active(page);
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} else {
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lru_cache_add(page);
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}
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put_page(page);
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}
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/*
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* Add isolated pages on the list back to the LRU.
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*
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* returns the number of pages put back.
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*/
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int putback_lru_pages(struct list_head *l)
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{
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struct page *page;
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struct page *page2;
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int count = 0;
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list_for_each_entry_safe(page, page2, l, lru) {
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list_del(&page->lru);
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move_to_lru(page);
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count++;
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}
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return count;
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}
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/*
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* Restore a potential migration pte to a working pte entry
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*/
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static void remove_migration_pte(struct vm_area_struct *vma,
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struct page *old, struct page *new)
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{
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struct mm_struct *mm = vma->vm_mm;
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swp_entry_t entry;
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *ptep, pte;
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spinlock_t *ptl;
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unsigned long addr = page_address_in_vma(new, vma);
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if (addr == -EFAULT)
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return;
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pgd = pgd_offset(mm, addr);
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if (!pgd_present(*pgd))
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return;
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pud = pud_offset(pgd, addr);
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if (!pud_present(*pud))
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return;
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pmd = pmd_offset(pud, addr);
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if (!pmd_present(*pmd))
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return;
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ptep = pte_offset_map(pmd, addr);
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if (!is_swap_pte(*ptep)) {
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pte_unmap(ptep);
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return;
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}
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if (mem_cgroup_charge(new, mm, GFP_KERNEL)) {
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pte_unmap(ptep);
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return;
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}
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ptl = pte_lockptr(mm, pmd);
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spin_lock(ptl);
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pte = *ptep;
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if (!is_swap_pte(pte))
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goto out;
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entry = pte_to_swp_entry(pte);
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if (!is_migration_entry(entry) || migration_entry_to_page(entry) != old)
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goto out;
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get_page(new);
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pte = pte_mkold(mk_pte(new, vma->vm_page_prot));
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if (is_write_migration_entry(entry))
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pte = pte_mkwrite(pte);
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flush_cache_page(vma, addr, pte_pfn(pte));
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set_pte_at(mm, addr, ptep, pte);
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if (PageAnon(new))
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page_add_anon_rmap(new, vma, addr);
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else
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page_add_file_rmap(new);
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/* No need to invalidate - it was non-present before */
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update_mmu_cache(vma, addr, pte);
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out:
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pte_unmap_unlock(ptep, ptl);
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}
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/*
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* Note that remove_file_migration_ptes will only work on regular mappings,
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* Nonlinear mappings do not use migration entries.
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*/
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static void remove_file_migration_ptes(struct page *old, struct page *new)
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{
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struct vm_area_struct *vma;
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struct address_space *mapping = page_mapping(new);
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struct prio_tree_iter iter;
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pgoff_t pgoff = new->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
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if (!mapping)
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return;
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spin_lock(&mapping->i_mmap_lock);
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vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff)
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remove_migration_pte(vma, old, new);
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spin_unlock(&mapping->i_mmap_lock);
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}
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/*
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* Must hold mmap_sem lock on at least one of the vmas containing
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* the page so that the anon_vma cannot vanish.
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*/
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static void remove_anon_migration_ptes(struct page *old, struct page *new)
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{
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struct anon_vma *anon_vma;
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struct vm_area_struct *vma;
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unsigned long mapping;
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mapping = (unsigned long)new->mapping;
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if (!mapping || (mapping & PAGE_MAPPING_ANON) == 0)
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return;
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/*
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* We hold the mmap_sem lock. So no need to call page_lock_anon_vma.
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*/
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anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON);
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spin_lock(&anon_vma->lock);
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list_for_each_entry(vma, &anon_vma->head, anon_vma_node)
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remove_migration_pte(vma, old, new);
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spin_unlock(&anon_vma->lock);
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}
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/*
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* Get rid of all migration entries and replace them by
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* references to the indicated page.
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*/
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static void remove_migration_ptes(struct page *old, struct page *new)
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{
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if (PageAnon(new))
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remove_anon_migration_ptes(old, new);
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else
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remove_file_migration_ptes(old, new);
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}
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/*
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* Something used the pte of a page under migration. We need to
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* get to the page and wait until migration is finished.
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* When we return from this function the fault will be retried.
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*
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* This function is called from do_swap_page().
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*/
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void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
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unsigned long address)
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{
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pte_t *ptep, pte;
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spinlock_t *ptl;
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swp_entry_t entry;
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struct page *page;
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ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
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pte = *ptep;
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if (!is_swap_pte(pte))
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goto out;
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entry = pte_to_swp_entry(pte);
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if (!is_migration_entry(entry))
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goto out;
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page = migration_entry_to_page(entry);
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get_page(page);
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pte_unmap_unlock(ptep, ptl);
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wait_on_page_locked(page);
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put_page(page);
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return;
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out:
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pte_unmap_unlock(ptep, ptl);
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}
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/*
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* Replace the page in the mapping.
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*
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* The number of remaining references must be:
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* 1 for anonymous pages without a mapping
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* 2 for pages with a mapping
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* 3 for pages with a mapping and PagePrivate set.
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*/
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static int migrate_page_move_mapping(struct address_space *mapping,
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struct page *newpage, struct page *page)
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{
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void **pslot;
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if (!mapping) {
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/* Anonymous page without mapping */
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if (page_count(page) != 1)
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return -EAGAIN;
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return 0;
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}
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write_lock_irq(&mapping->tree_lock);
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pslot = radix_tree_lookup_slot(&mapping->page_tree,
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page_index(page));
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if (page_count(page) != 2 + !!PagePrivate(page) ||
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(struct page *)radix_tree_deref_slot(pslot) != page) {
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write_unlock_irq(&mapping->tree_lock);
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return -EAGAIN;
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}
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/*
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* Now we know that no one else is looking at the page.
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*/
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get_page(newpage); /* add cache reference */
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#ifdef CONFIG_SWAP
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if (PageSwapCache(page)) {
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SetPageSwapCache(newpage);
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set_page_private(newpage, page_private(page));
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}
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#endif
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radix_tree_replace_slot(pslot, newpage);
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/*
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* Drop cache reference from old page.
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* We know this isn't the last reference.
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*/
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__put_page(page);
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/*
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* If moved to a different zone then also account
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* the page for that zone. Other VM counters will be
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* taken care of when we establish references to the
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* new page and drop references to the old page.
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*
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* Note that anonymous pages are accounted for
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* via NR_FILE_PAGES and NR_ANON_PAGES if they
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* are mapped to swap space.
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*/
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__dec_zone_page_state(page, NR_FILE_PAGES);
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__inc_zone_page_state(newpage, NR_FILE_PAGES);
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write_unlock_irq(&mapping->tree_lock);
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return 0;
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}
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/*
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* Copy the page to its new location
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*/
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static void migrate_page_copy(struct page *newpage, struct page *page)
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{
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copy_highpage(newpage, page);
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if (PageError(page))
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SetPageError(newpage);
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if (PageReferenced(page))
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SetPageReferenced(newpage);
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if (PageUptodate(page))
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SetPageUptodate(newpage);
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if (PageActive(page))
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SetPageActive(newpage);
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if (PageChecked(page))
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SetPageChecked(newpage);
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if (PageMappedToDisk(page))
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SetPageMappedToDisk(newpage);
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if (PageDirty(page)) {
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clear_page_dirty_for_io(page);
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set_page_dirty(newpage);
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}
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#ifdef CONFIG_SWAP
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ClearPageSwapCache(page);
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#endif
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ClearPageActive(page);
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ClearPagePrivate(page);
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set_page_private(page, 0);
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page->mapping = NULL;
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/*
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* If any waiters have accumulated on the new page then
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* wake them up.
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*/
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if (PageWriteback(newpage))
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end_page_writeback(newpage);
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}
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/************************************************************
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* Migration functions
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***********************************************************/
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/* Always fail migration. Used for mappings that are not movable */
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int fail_migrate_page(struct address_space *mapping,
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struct page *newpage, struct page *page)
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{
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return -EIO;
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}
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EXPORT_SYMBOL(fail_migrate_page);
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/*
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* Common logic to directly migrate a single page suitable for
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* pages that do not use PagePrivate.
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*
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* Pages are locked upon entry and exit.
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*/
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int migrate_page(struct address_space *mapping,
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struct page *newpage, struct page *page)
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{
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int rc;
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BUG_ON(PageWriteback(page)); /* Writeback must be complete */
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rc = migrate_page_move_mapping(mapping, newpage, page);
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if (rc)
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return rc;
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migrate_page_copy(newpage, page);
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return 0;
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}
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EXPORT_SYMBOL(migrate_page);
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#ifdef CONFIG_BLOCK
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/*
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* Migration function for pages with buffers. This function can only be used
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* if the underlying filesystem guarantees that no other references to "page"
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* exist.
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*/
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int buffer_migrate_page(struct address_space *mapping,
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struct page *newpage, struct page *page)
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{
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struct buffer_head *bh, *head;
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int rc;
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if (!page_has_buffers(page))
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return migrate_page(mapping, newpage, page);
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head = page_buffers(page);
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rc = migrate_page_move_mapping(mapping, newpage, page);
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if (rc)
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return rc;
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bh = head;
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do {
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get_bh(bh);
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lock_buffer(bh);
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bh = bh->b_this_page;
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} while (bh != head);
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ClearPagePrivate(page);
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set_page_private(newpage, page_private(page));
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set_page_private(page, 0);
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put_page(page);
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get_page(newpage);
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bh = head;
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do {
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set_bh_page(bh, newpage, bh_offset(bh));
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bh = bh->b_this_page;
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} while (bh != head);
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SetPagePrivate(newpage);
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migrate_page_copy(newpage, page);
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bh = head;
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do {
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unlock_buffer(bh);
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put_bh(bh);
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bh = bh->b_this_page;
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} while (bh != head);
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return 0;
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}
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EXPORT_SYMBOL(buffer_migrate_page);
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#endif
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/*
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* Writeback a page to clean the dirty state
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*/
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static int writeout(struct address_space *mapping, struct page *page)
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{
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struct writeback_control wbc = {
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.sync_mode = WB_SYNC_NONE,
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.nr_to_write = 1,
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.range_start = 0,
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.range_end = LLONG_MAX,
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.nonblocking = 1,
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.for_reclaim = 1
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};
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int rc;
|
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|
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if (!mapping->a_ops->writepage)
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/* No write method for the address space */
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return -EINVAL;
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|
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if (!clear_page_dirty_for_io(page))
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/* Someone else already triggered a write */
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return -EAGAIN;
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|
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/*
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* A dirty page may imply that the underlying filesystem has
|
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* the page on some queue. So the page must be clean for
|
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* migration. Writeout may mean we loose the lock and the
|
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* page state is no longer what we checked for earlier.
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* At this point we know that the migration attempt cannot
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* be successful.
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*/
|
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remove_migration_ptes(page, page);
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|
|
rc = mapping->a_ops->writepage(page, &wbc);
|
|
if (rc < 0)
|
|
/* I/O Error writing */
|
|
return -EIO;
|
|
|
|
if (rc != AOP_WRITEPAGE_ACTIVATE)
|
|
/* unlocked. Relock */
|
|
lock_page(page);
|
|
|
|
return -EAGAIN;
|
|
}
|
|
|
|
/*
|
|
* Default handling if a filesystem does not provide a migration function.
|
|
*/
|
|
static int fallback_migrate_page(struct address_space *mapping,
|
|
struct page *newpage, struct page *page)
|
|
{
|
|
if (PageDirty(page))
|
|
return writeout(mapping, page);
|
|
|
|
/*
|
|
* Buffers may be managed in a filesystem specific way.
|
|
* We must have no buffers or drop them.
|
|
*/
|
|
if (PagePrivate(page) &&
|
|
!try_to_release_page(page, GFP_KERNEL))
|
|
return -EAGAIN;
|
|
|
|
return migrate_page(mapping, newpage, page);
|
|
}
|
|
|
|
/*
|
|
* Move a page to a newly allocated page
|
|
* The page is locked and all ptes have been successfully removed.
|
|
*
|
|
* The new page will have replaced the old page if this function
|
|
* is successful.
|
|
*/
|
|
static int move_to_new_page(struct page *newpage, struct page *page)
|
|
{
|
|
struct address_space *mapping;
|
|
int rc;
|
|
|
|
/*
|
|
* Block others from accessing the page when we get around to
|
|
* establishing additional references. We are the only one
|
|
* holding a reference to the new page at this point.
|
|
*/
|
|
if (TestSetPageLocked(newpage))
|
|
BUG();
|
|
|
|
/* Prepare mapping for the new page.*/
|
|
newpage->index = page->index;
|
|
newpage->mapping = page->mapping;
|
|
|
|
mapping = page_mapping(page);
|
|
if (!mapping)
|
|
rc = migrate_page(mapping, newpage, page);
|
|
else if (mapping->a_ops->migratepage)
|
|
/*
|
|
* Most pages have a mapping and most filesystems
|
|
* should provide a migration function. Anonymous
|
|
* pages are part of swap space which also has its
|
|
* own migration function. This is the most common
|
|
* path for page migration.
|
|
*/
|
|
rc = mapping->a_ops->migratepage(mapping,
|
|
newpage, page);
|
|
else
|
|
rc = fallback_migrate_page(mapping, newpage, page);
|
|
|
|
if (!rc) {
|
|
mem_cgroup_page_migration(page, newpage);
|
|
remove_migration_ptes(page, newpage);
|
|
} else
|
|
newpage->mapping = NULL;
|
|
|
|
unlock_page(newpage);
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* Obtain the lock on page, remove all ptes and migrate the page
|
|
* to the newly allocated page in newpage.
|
|
*/
|
|
static int unmap_and_move(new_page_t get_new_page, unsigned long private,
|
|
struct page *page, int force)
|
|
{
|
|
int rc = 0;
|
|
int *result = NULL;
|
|
struct page *newpage = get_new_page(page, private, &result);
|
|
int rcu_locked = 0;
|
|
int charge = 0;
|
|
|
|
if (!newpage)
|
|
return -ENOMEM;
|
|
|
|
if (page_count(page) == 1)
|
|
/* page was freed from under us. So we are done. */
|
|
goto move_newpage;
|
|
|
|
rc = -EAGAIN;
|
|
if (TestSetPageLocked(page)) {
|
|
if (!force)
|
|
goto move_newpage;
|
|
lock_page(page);
|
|
}
|
|
|
|
if (PageWriteback(page)) {
|
|
if (!force)
|
|
goto unlock;
|
|
wait_on_page_writeback(page);
|
|
}
|
|
/*
|
|
* By try_to_unmap(), page->mapcount goes down to 0 here. In this case,
|
|
* we cannot notice that anon_vma is freed while we migrates a page.
|
|
* This rcu_read_lock() delays freeing anon_vma pointer until the end
|
|
* of migration. File cache pages are no problem because of page_lock()
|
|
* File Caches may use write_page() or lock_page() in migration, then,
|
|
* just care Anon page here.
|
|
*/
|
|
if (PageAnon(page)) {
|
|
rcu_read_lock();
|
|
rcu_locked = 1;
|
|
}
|
|
|
|
/*
|
|
* Corner case handling:
|
|
* 1. When a new swap-cache page is read into, it is added to the LRU
|
|
* and treated as swapcache but it has no rmap yet.
|
|
* Calling try_to_unmap() against a page->mapping==NULL page will
|
|
* trigger a BUG. So handle it here.
|
|
* 2. An orphaned page (see truncate_complete_page) might have
|
|
* fs-private metadata. The page can be picked up due to memory
|
|
* offlining. Everywhere else except page reclaim, the page is
|
|
* invisible to the vm, so the page can not be migrated. So try to
|
|
* free the metadata, so the page can be freed.
|
|
*/
|
|
if (!page->mapping) {
|
|
if (!PageAnon(page) && PagePrivate(page)) {
|
|
/*
|
|
* Go direct to try_to_free_buffers() here because
|
|
* a) that's what try_to_release_page() would do anyway
|
|
* b) we may be under rcu_read_lock() here, so we can't
|
|
* use GFP_KERNEL which is what try_to_release_page()
|
|
* needs to be effective.
|
|
*/
|
|
try_to_free_buffers(page);
|
|
}
|
|
goto rcu_unlock;
|
|
}
|
|
|
|
charge = mem_cgroup_prepare_migration(page);
|
|
/* Establish migration ptes or remove ptes */
|
|
try_to_unmap(page, 1);
|
|
|
|
if (!page_mapped(page))
|
|
rc = move_to_new_page(newpage, page);
|
|
|
|
if (rc) {
|
|
remove_migration_ptes(page, page);
|
|
if (charge)
|
|
mem_cgroup_end_migration(page);
|
|
} else if (charge)
|
|
mem_cgroup_end_migration(newpage);
|
|
rcu_unlock:
|
|
if (rcu_locked)
|
|
rcu_read_unlock();
|
|
|
|
unlock:
|
|
|
|
unlock_page(page);
|
|
|
|
if (rc != -EAGAIN) {
|
|
/*
|
|
* A page that has been migrated has all references
|
|
* removed and will be freed. A page that has not been
|
|
* migrated will have kepts its references and be
|
|
* restored.
|
|
*/
|
|
list_del(&page->lru);
|
|
move_to_lru(page);
|
|
}
|
|
|
|
move_newpage:
|
|
/*
|
|
* Move the new page to the LRU. If migration was not successful
|
|
* then this will free the page.
|
|
*/
|
|
move_to_lru(newpage);
|
|
if (result) {
|
|
if (rc)
|
|
*result = rc;
|
|
else
|
|
*result = page_to_nid(newpage);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* migrate_pages
|
|
*
|
|
* The function takes one list of pages to migrate and a function
|
|
* that determines from the page to be migrated and the private data
|
|
* the target of the move and allocates the page.
|
|
*
|
|
* The function returns after 10 attempts or if no pages
|
|
* are movable anymore because to has become empty
|
|
* or no retryable pages exist anymore. All pages will be
|
|
* returned to the LRU or freed.
|
|
*
|
|
* Return: Number of pages not migrated or error code.
|
|
*/
|
|
int migrate_pages(struct list_head *from,
|
|
new_page_t get_new_page, unsigned long private)
|
|
{
|
|
int retry = 1;
|
|
int nr_failed = 0;
|
|
int pass = 0;
|
|
struct page *page;
|
|
struct page *page2;
|
|
int swapwrite = current->flags & PF_SWAPWRITE;
|
|
int rc;
|
|
|
|
if (!swapwrite)
|
|
current->flags |= PF_SWAPWRITE;
|
|
|
|
for(pass = 0; pass < 10 && retry; pass++) {
|
|
retry = 0;
|
|
|
|
list_for_each_entry_safe(page, page2, from, lru) {
|
|
cond_resched();
|
|
|
|
rc = unmap_and_move(get_new_page, private,
|
|
page, pass > 2);
|
|
|
|
switch(rc) {
|
|
case -ENOMEM:
|
|
goto out;
|
|
case -EAGAIN:
|
|
retry++;
|
|
break;
|
|
case 0:
|
|
break;
|
|
default:
|
|
/* Permanent failure */
|
|
nr_failed++;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
rc = 0;
|
|
out:
|
|
if (!swapwrite)
|
|
current->flags &= ~PF_SWAPWRITE;
|
|
|
|
putback_lru_pages(from);
|
|
|
|
if (rc)
|
|
return rc;
|
|
|
|
return nr_failed + retry;
|
|
}
|
|
|
|
#ifdef CONFIG_NUMA
|
|
/*
|
|
* Move a list of individual pages
|
|
*/
|
|
struct page_to_node {
|
|
unsigned long addr;
|
|
struct page *page;
|
|
int node;
|
|
int status;
|
|
};
|
|
|
|
static struct page *new_page_node(struct page *p, unsigned long private,
|
|
int **result)
|
|
{
|
|
struct page_to_node *pm = (struct page_to_node *)private;
|
|
|
|
while (pm->node != MAX_NUMNODES && pm->page != p)
|
|
pm++;
|
|
|
|
if (pm->node == MAX_NUMNODES)
|
|
return NULL;
|
|
|
|
*result = &pm->status;
|
|
|
|
return alloc_pages_node(pm->node,
|
|
GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0);
|
|
}
|
|
|
|
/*
|
|
* Move a set of pages as indicated in the pm array. The addr
|
|
* field must be set to the virtual address of the page to be moved
|
|
* and the node number must contain a valid target node.
|
|
*/
|
|
static int do_move_pages(struct mm_struct *mm, struct page_to_node *pm,
|
|
int migrate_all)
|
|
{
|
|
int err;
|
|
struct page_to_node *pp;
|
|
LIST_HEAD(pagelist);
|
|
|
|
down_read(&mm->mmap_sem);
|
|
|
|
/*
|
|
* Build a list of pages to migrate
|
|
*/
|
|
migrate_prep();
|
|
for (pp = pm; pp->node != MAX_NUMNODES; pp++) {
|
|
struct vm_area_struct *vma;
|
|
struct page *page;
|
|
|
|
/*
|
|
* A valid page pointer that will not match any of the
|
|
* pages that will be moved.
|
|
*/
|
|
pp->page = ZERO_PAGE(0);
|
|
|
|
err = -EFAULT;
|
|
vma = find_vma(mm, pp->addr);
|
|
if (!vma || !vma_migratable(vma))
|
|
goto set_status;
|
|
|
|
page = follow_page(vma, pp->addr, FOLL_GET);
|
|
err = -ENOENT;
|
|
if (!page)
|
|
goto set_status;
|
|
|
|
if (PageReserved(page)) /* Check for zero page */
|
|
goto put_and_set;
|
|
|
|
pp->page = page;
|
|
err = page_to_nid(page);
|
|
|
|
if (err == pp->node)
|
|
/*
|
|
* Node already in the right place
|
|
*/
|
|
goto put_and_set;
|
|
|
|
err = -EACCES;
|
|
if (page_mapcount(page) > 1 &&
|
|
!migrate_all)
|
|
goto put_and_set;
|
|
|
|
err = isolate_lru_page(page, &pagelist);
|
|
put_and_set:
|
|
/*
|
|
* Either remove the duplicate refcount from
|
|
* isolate_lru_page() or drop the page ref if it was
|
|
* not isolated.
|
|
*/
|
|
put_page(page);
|
|
set_status:
|
|
pp->status = err;
|
|
}
|
|
|
|
if (!list_empty(&pagelist))
|
|
err = migrate_pages(&pagelist, new_page_node,
|
|
(unsigned long)pm);
|
|
else
|
|
err = -ENOENT;
|
|
|
|
up_read(&mm->mmap_sem);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Determine the nodes of a list of pages. The addr in the pm array
|
|
* must have been set to the virtual address of which we want to determine
|
|
* the node number.
|
|
*/
|
|
static int do_pages_stat(struct mm_struct *mm, struct page_to_node *pm)
|
|
{
|
|
down_read(&mm->mmap_sem);
|
|
|
|
for ( ; pm->node != MAX_NUMNODES; pm++) {
|
|
struct vm_area_struct *vma;
|
|
struct page *page;
|
|
int err;
|
|
|
|
err = -EFAULT;
|
|
vma = find_vma(mm, pm->addr);
|
|
if (!vma)
|
|
goto set_status;
|
|
|
|
page = follow_page(vma, pm->addr, 0);
|
|
err = -ENOENT;
|
|
/* Use PageReserved to check for zero page */
|
|
if (!page || PageReserved(page))
|
|
goto set_status;
|
|
|
|
err = page_to_nid(page);
|
|
set_status:
|
|
pm->status = err;
|
|
}
|
|
|
|
up_read(&mm->mmap_sem);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Move a list of pages in the address space of the currently executing
|
|
* process.
|
|
*/
|
|
asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
|
|
const void __user * __user *pages,
|
|
const int __user *nodes,
|
|
int __user *status, int flags)
|
|
{
|
|
int err = 0;
|
|
int i;
|
|
struct task_struct *task;
|
|
nodemask_t task_nodes;
|
|
struct mm_struct *mm;
|
|
struct page_to_node *pm = NULL;
|
|
|
|
/* Check flags */
|
|
if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
|
|
return -EINVAL;
|
|
|
|
if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
|
|
return -EPERM;
|
|
|
|
/* Find the mm_struct */
|
|
read_lock(&tasklist_lock);
|
|
task = pid ? find_task_by_vpid(pid) : current;
|
|
if (!task) {
|
|
read_unlock(&tasklist_lock);
|
|
return -ESRCH;
|
|
}
|
|
mm = get_task_mm(task);
|
|
read_unlock(&tasklist_lock);
|
|
|
|
if (!mm)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Check if this process has the right to modify the specified
|
|
* process. The right exists if the process has administrative
|
|
* capabilities, superuser privileges or the same
|
|
* userid as the target process.
|
|
*/
|
|
if ((current->euid != task->suid) && (current->euid != task->uid) &&
|
|
(current->uid != task->suid) && (current->uid != task->uid) &&
|
|
!capable(CAP_SYS_NICE)) {
|
|
err = -EPERM;
|
|
goto out2;
|
|
}
|
|
|
|
err = security_task_movememory(task);
|
|
if (err)
|
|
goto out2;
|
|
|
|
|
|
task_nodes = cpuset_mems_allowed(task);
|
|
|
|
/* Limit nr_pages so that the multiplication may not overflow */
|
|
if (nr_pages >= ULONG_MAX / sizeof(struct page_to_node) - 1) {
|
|
err = -E2BIG;
|
|
goto out2;
|
|
}
|
|
|
|
pm = vmalloc((nr_pages + 1) * sizeof(struct page_to_node));
|
|
if (!pm) {
|
|
err = -ENOMEM;
|
|
goto out2;
|
|
}
|
|
|
|
/*
|
|
* Get parameters from user space and initialize the pm
|
|
* array. Return various errors if the user did something wrong.
|
|
*/
|
|
for (i = 0; i < nr_pages; i++) {
|
|
const void __user *p;
|
|
|
|
err = -EFAULT;
|
|
if (get_user(p, pages + i))
|
|
goto out;
|
|
|
|
pm[i].addr = (unsigned long)p;
|
|
if (nodes) {
|
|
int node;
|
|
|
|
if (get_user(node, nodes + i))
|
|
goto out;
|
|
|
|
err = -ENODEV;
|
|
if (!node_state(node, N_HIGH_MEMORY))
|
|
goto out;
|
|
|
|
err = -EACCES;
|
|
if (!node_isset(node, task_nodes))
|
|
goto out;
|
|
|
|
pm[i].node = node;
|
|
} else
|
|
pm[i].node = 0; /* anything to not match MAX_NUMNODES */
|
|
}
|
|
/* End marker */
|
|
pm[nr_pages].node = MAX_NUMNODES;
|
|
|
|
if (nodes)
|
|
err = do_move_pages(mm, pm, flags & MPOL_MF_MOVE_ALL);
|
|
else
|
|
err = do_pages_stat(mm, pm);
|
|
|
|
if (err >= 0)
|
|
/* Return status information */
|
|
for (i = 0; i < nr_pages; i++)
|
|
if (put_user(pm[i].status, status + i))
|
|
err = -EFAULT;
|
|
|
|
out:
|
|
vfree(pm);
|
|
out2:
|
|
mmput(mm);
|
|
return err;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Call migration functions in the vma_ops that may prepare
|
|
* memory in a vm for migration. migration functions may perform
|
|
* the migration for vmas that do not have an underlying page struct.
|
|
*/
|
|
int migrate_vmas(struct mm_struct *mm, const nodemask_t *to,
|
|
const nodemask_t *from, unsigned long flags)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
int err = 0;
|
|
|
|
for(vma = mm->mmap; vma->vm_next && !err; vma = vma->vm_next) {
|
|
if (vma->vm_ops && vma->vm_ops->migrate) {
|
|
err = vma->vm_ops->migrate(vma, to, from, flags);
|
|
if (err)
|
|
break;
|
|
}
|
|
}
|
|
return err;
|
|
}
|