Merge branches 'perf-urgent-for-linus', 'x86-urgent-for-linus' and 'sched-urgent...

[linux-flexiantxendom0-3.2.10.git] / mm / ksm.c

diff --git a/mm/ksm.c b/mm/ksm.c
index 1bbe785..47c8853 100644 (file)
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -35,6 +35,7 @@
 #include <linux/ksm.h>
 #include <linux/hash.h>
 #include <linux/freezer.h>
+#include <linux/oom.h>
 
 #include <asm/tlbflush.h>
 #include "internal.h"
@@ -373,6 +374,20 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
        return (ret & VM_FAULT_OOM) ? -ENOMEM : 0;
 }
 
+static struct vm_area_struct *find_mergeable_vma(struct mm_struct *mm,
+               unsigned long addr)
+{
+       struct vm_area_struct *vma;
+       if (ksm_test_exit(mm))
+               return NULL;
+       vma = find_vma(mm, addr);
+       if (!vma || vma->vm_start > addr)
+               return NULL;
+       if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
+               return NULL;
+       return vma;
+}
+
 static void break_cow(struct rmap_item *rmap_item)
 {
        struct mm_struct *mm = rmap_item->mm;
@@ -386,15 +401,9 @@ static void break_cow(struct rmap_item *rmap_item)
        put_anon_vma(rmap_item->anon_vma);
 
        down_read(&mm->mmap_sem);
-       if (ksm_test_exit(mm))
-               goto out;
-       vma = find_vma(mm, addr);
-       if (!vma || vma->vm_start > addr)
-               goto out;
-       if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
-               goto out;
-       break_ksm(vma, addr);
-out:
+       vma = find_mergeable_vma(mm, addr);
+       if (vma)
+               break_ksm(vma, addr);
        up_read(&mm->mmap_sem);
 }
 
@@ -420,12 +429,8 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
        struct page *page;
 
        down_read(&mm->mmap_sem);
-       if (ksm_test_exit(mm))
-               goto out;
-       vma = find_vma(mm, addr);
-       if (!vma || vma->vm_start > addr)
-               goto out;
-       if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
+       vma = find_mergeable_vma(mm, addr);
+       if (!vma)
                goto out;
 
        page = follow_page(vma, addr, FOLL_GET);
@@ -671,9 +676,9 @@ error:
 static u32 calc_checksum(struct page *page)
 {
        u32 checksum;
-       void *addr = kmap_atomic(page, KM_USER0);
+       void *addr = kmap_atomic(page);
        checksum = jhash2(addr, PAGE_SIZE / 4, 17);
-       kunmap_atomic(addr, KM_USER0);
+       kunmap_atomic(addr);
        return checksum;
 }
 
@@ -682,11 +687,11 @@ static int memcmp_pages(struct page *page1, struct page *page2)
        char *addr1, *addr2;
        int ret;
 
-       addr1 = kmap_atomic(page1, KM_USER0);
-       addr2 = kmap_atomic(page2, KM_USER1);
+       addr1 = kmap_atomic(page1);
+       addr2 = kmap_atomic(page2);
        ret = memcmp(addr1, addr2, PAGE_SIZE);
-       kunmap_atomic(addr2, KM_USER1);
-       kunmap_atomic(addr1, KM_USER0);
+       kunmap_atomic(addr2);
+       kunmap_atomic(addr1);
        return ret;
 }
 
@@ -720,7 +725,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
                swapped = PageSwapCache(page);
                flush_cache_page(vma, addr, page_to_pfn(page));
                /*
-                * Ok this is tricky, when get_user_pages_fast() run it doesnt
+                * Ok this is tricky, when get_user_pages_fast() run it doesn't
                 * take any lock, therefore the check that we are going to make
                 * with the pagecount against the mapcount is racey and
                 * O_DIRECT can happen right after the check.
@@ -1301,6 +1306,12 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
                slot = list_entry(slot->mm_list.next, struct mm_slot, mm_list);
                ksm_scan.mm_slot = slot;
                spin_unlock(&ksm_mmlist_lock);
+               /*
+                * Although we tested list_empty() above, a racing __ksm_exit
+                * of the last mm on the list may have removed it since then.
+                */
+               if (slot == &ksm_mm_head)
+                       return NULL;
 next_mm:
                ksm_scan.address = 0;
                ksm_scan.rmap_list = &slot->rmap_list;
@@ -1894,9 +1905,12 @@ static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr,
        if (ksm_run != flags) {
                ksm_run = flags;
                if (flags & KSM_RUN_UNMERGE) {
-                       current->flags |= PF_OOM_ORIGIN;
+                       int oom_score_adj;
+
+                       oom_score_adj = test_set_oom_score_adj(OOM_SCORE_ADJ_MAX);
                        err = unmerge_and_remove_all_rmap_items();
-                       current->flags &= ~PF_OOM_ORIGIN;
+                       compare_swap_oom_score_adj(OOM_SCORE_ADJ_MAX,
+                                                               oom_score_adj);
                        if (err) {
                                ksm_run = KSM_RUN_STOP;
                                count = err;