| Re: KVM support on 2.6.18-164.2.1.el5.028stab066.7 (CentOS5.4) [message #38344 is a reply to message #38225] |
Wed, 09 December 2009 11:46  |
jmslkn
Messages: 19
Registered: June 2007
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Junior Member |
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I have the same panic here, when I start the ksm service. It seems there is a page that is allocated on different path without "charging" it, and when the memory manager try to free that page (free_hot_cold_page), it crashes.
The relevant source lines are here:
/kernel/ub/ub_mem.c
/*
* Pages accounting
*/
int ub_page_charge(struct page *page, int order, gfp_t mask)
{
struct user_beancounter *ub;
unsigned long flags;
ub = NULL;
if (!(mask & __GFP_UBC))
goto out;
ub = get_beancounter(get_exec_ub());
if (ub == NULL)
goto out;
local_irq_save(flags);
if (ub_kmemsize_charge(ub, CHARGE_ORDER(order),
(mask & __GFP_SOFT_UBC ? UB_SOFT : UB_HARD)))
goto err;
inc_pages_charged(ub, order);
local_irq_restore(flags);
out:
BUG_ON(page_ub(page) != NULL);
page_ub(page) = ub;
return 0;
err:
local_irq_restore(flags);
BUG_ON(page_ub(page) != NULL);
put_beancounter(ub);
return -ENOMEM;
}
void ub_page_uncharge(struct page *page, int order)
{
struct user_beancounter *ub;
unsigned long flags;
ub = page_ub(page);
if (ub == NULL)
return;
BUG_ON(ub->ub_magic != UB_MAGIC);
dec_pages_charged(ub, order);
local_irq_save(flags);
ub_kmemsize_uncharge(ub, CHARGE_ORDER(order));
local_irq_restore(flags);
put_beancounter(ub);
page_ub(page) = NULL;
}
ksm/ksm_main.c
static int try_to_merge_two_pages_alloc(struct mm_struct *mm1,
struct page *page1,
struct mm_struct *mm2,
struct page *page2,
unsigned long addr1,
unsigned long addr2)
{
struct vm_area_struct *vma;
pgprot_t prot;
int ret = 1;
struct page *kpage;
kpage = alloc_page(GFP_HIGHUSER);
if (!kpage)
return ret;
down_read(&mm1->mmap_sem);
vma = find_vma(mm1, addr1);
if (!vma) {
put_page(kpage);
up_read(&mm1->mmap_sem);
return ret;
}
prot = vma->vm_page_prot;
pgprot_val(prot) &= ~_PAGE_RW;
copy_user_highpage(kpage, page1, addr1);
ret = try_to_merge_one_page(mm1, vma, page1, kpage, prot);
up_read(&mm1->mmap_sem);
[..]
However the alloc_page calls __alloc_page function, that is "charged". Any idea?
-
Attachment: ksm.tar.gz
(Size: 13.25KB, Downloaded 310 times)
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