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ksm: remove unswappable max_kernel_pages

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ksm: fix bad user data when swapping
thp: ksm: free swap when swapcache page is replaced
This commit is contained in:
SecureCRT 2012-08-17 01:19:24 +08:00
parent 0c4a37e304
commit cc0db50c33
1 changed files with 18 additions and 38 deletions
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56
mm/ksm.c Normal file → Executable file
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@ -163,9 +163,6 @@ static unsigned long ksm_pages_unshared;
/* The number of rmap_items in use: to calculate pages_volatile */
static unsigned long ksm_rmap_items;
/* Limit on the number of unswappable pages used */
static unsigned long ksm_max_kernel_pages;
/* Number of pages ksmd should scan in one batch */
static unsigned int ksm_thread_pages_to_scan = 100;
@ -628,7 +625,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
if (!ptep)
goto out;
if (pte_write(*ptep)) {
if (pte_write(*ptep) || pte_dirty(*ptep)) {
pte_t entry;
swapped = PageSwapCache(page);
@ -651,7 +648,9 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
set_pte_at_notify(mm, addr, ptep, entry);
goto out_unlock;
}
entry = pte_wrprotect(entry);
if (pte_dirty(entry))
set_page_dirty(page);
entry = pte_mkclean(pte_wrprotect(entry));
set_pte_at_notify(mm, addr, ptep, entry);
}
*orig_pte = *ptep;
@ -717,6 +716,8 @@ static int replace_page(struct vm_area_struct *vma, struct page *oldpage,
set_pte_at_notify(mm, addr, ptep, mk_pte(newpage, prot));
page_remove_rmap(oldpage);
if (!page_mapped(oldpage))
try_to_free_swap(oldpage);
put_page(oldpage);
pte_unmap_unlock(ptep, ptl);
@ -827,13 +828,6 @@ static int try_to_merge_two_pages(struct mm_struct *mm1, unsigned long addr1,
struct page *kpage;
int err = -EFAULT;
/*
* The number of nodes in the stable tree
* is the number of kernel pages that we hold.
*/
if (ksm_max_kernel_pages &&
ksm_max_kernel_pages <= ksm_pages_shared)
return err;
kpage = alloc_page(GFP_HIGHUSER);
if (!kpage)
@ -1209,6 +1203,18 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
slot = ksm_scan.mm_slot;
if (slot == &ksm_mm_head) {
/*
* A number of pages can hang around indefinitely on per-cpu
* pagevecs, raised page count preventing write_protect_page
* from merging them. Though it doesn't really matter much,
* it is puzzling to see some stuck in pages_volatile until
* other activity jostles them out, and they also prevented
* LTP's KSM test from succeeding deterministically; so drain
* them here (here rather than on entry to ksm_do_scan(),
* so we don't IPI too often when pages_to_scan is set low).
*/
lru_add_drain_all();
root_unstable_tree = RB_ROOT;
spin_lock(&ksm_mmlist_lock);
@ -1577,29 +1583,6 @@ static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr,
}
KSM_ATTR(run);
static ssize_t max_kernel_pages_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int err;
unsigned long nr_pages;
err = strict_strtoul(buf, 10, &nr_pages);
if (err)
return -EINVAL;
ksm_max_kernel_pages = nr_pages;
return count;
}
static ssize_t max_kernel_pages_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%lu\n", ksm_max_kernel_pages);
}
KSM_ATTR(max_kernel_pages);
static ssize_t pages_shared_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
@ -1649,7 +1632,6 @@ static struct attribute *ksm_attrs[] = {
&sleep_millisecs_attr.attr,
&pages_to_scan_attr.attr,
&run_attr.attr,
&max_kernel_pages_attr.attr,
&pages_shared_attr.attr,
&pages_sharing_attr.attr,
&pages_unshared_attr.attr,
@ -1669,8 +1651,6 @@ static int __init ksm_init(void)
struct task_struct *ksm_thread;
int err;
ksm_max_kernel_pages = totalram_pages / 4;
err = ksm_slab_init();
if (err)
goto out;