nagai/kernel
3
0
Fork 0
forked from mirrors/linux
Code Pull requests Activity

mm: wrap calls to set_pte_at_notify with invalidate_range_start and invalidate_range_end

Browse source 
In order to allow sleeping during invalidate_page mmu notifier calls, we
need to avoid calling when holding the PT lock.  In addition to its direct
calls, invalidate_page can also be called as a substitute for a change_pte
call, in case the notifier client hasn't implemented change_pte.

This patch drops the invalidate_page call from change_pte, and instead
wraps all calls to change_pte with invalidate_range_start and
invalidate_range_end calls.

Note that change_pte still cannot sleep after this patch, and that clients
implementing change_pte should not take action on it in case the number of
outstanding invalidate_range_start calls is larger than one, otherwise
they might miss a later invalidation.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Cc: Andrea Arcangeli <andrea@qumranet.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Haggai Eran <haggaie@mellanox.com>
Cc: Shachar Raindel <raindel@mellanox.com>
Cc: Liran Liss <liranl@mellanox.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Haggai Eran 2012-10-08 16:33:35 -07:00 committed by Linus Torvalds
parent 2ec74c3ef2
commit 6bdb913f0a
4 changed files with 36 additions and 14 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

5
kernel/events/uprobes.c
View file

@ -141,10 +141,14 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
spinlock_t *ptl;
pte_t *ptep;
int err;
/* For mmu_notifiers */
const unsigned long mmun_start = addr;
const unsigned long mmun_end = addr + PAGE_SIZE;
/* For try_to_free_swap() and munlock_vma_page() below */
lock_page(page);
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
err = -EAGAIN;
ptep = page_check_address(page, mm, addr, &ptl, 0);
if (!ptep)
@ -173,6 +177,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
err = 0;
unlock:
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
unlock_page(page);
return err;
}

21
mm/ksm.c
View file

@ -709,15 +709,22 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
spinlock_t *ptl;
int swapped;
int err = -EFAULT;
unsigned long mmun_start; /* For mmu_notifiers */
unsigned long mmun_end; /* For mmu_notifiers */
addr = page_address_in_vma(page, vma);
if (addr == -EFAULT)
goto out;
BUG_ON(PageTransCompound(page));
mmun_start = addr;
mmun_end = addr + PAGE_SIZE;
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
ptep = page_check_address(page, mm, addr, &ptl, 0);
if (!ptep)
goto out;
goto out_mn;
if (pte_write(*ptep) || pte_dirty(*ptep)) {
pte_t entry;
@ -752,6 +759,8 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
out_unlock:
pte_unmap_unlock(ptep, ptl);
out_mn:
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
out:
return err;
}
@ -776,6 +785,8 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
spinlock_t *ptl;
unsigned long addr;
int err = -EFAULT;
unsigned long mmun_start; /* For mmu_notifiers */
unsigned long mmun_end; /* For mmu_notifiers */
addr = page_address_in_vma(page, vma);
if (addr == -EFAULT)
@ -794,10 +805,14 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
if (!pmd_present(*pmd))
goto out;
mmun_start = addr;
mmun_end = addr + PAGE_SIZE;
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
ptep = pte_offset_map_lock(mm, pmd, addr, &ptl);
if (!pte_same(*ptep, orig_pte)) {
pte_unmap_unlock(ptep, ptl);
goto out;
goto out_mn;
}
get_page(kpage);
@ -814,6 +829,8 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
pte_unmap_unlock(ptep, ptl);
err = 0;
out_mn:
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
out:
return err;
}

18
mm/memory.c
View file

@ -2527,6 +2527,9 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
int ret = 0;
int page_mkwrite = 0;
struct page *dirty_page = NULL;
unsigned long mmun_start; /* For mmu_notifiers */
unsigned long mmun_end; /* For mmu_notifiers */
bool mmun_called = false; /* For mmu_notifiers */
old_page = vm_normal_page(vma, address, orig_pte);
if (!old_page) {
@ -2704,6 +2707,11 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
goto oom_free_new;
mmun_start = address & PAGE_MASK;
mmun_end = (address & PAGE_MASK) + PAGE_SIZE;
mmun_called = true;
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
/*
* Re-check the pte - we dropped the lock
*/
@ -2766,14 +2774,12 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
} else
mem_cgroup_uncharge_page(new_page);
if (new_page)
page_cache_release(new_page);
unlock:
pte_unmap_unlock(page_table, ptl);
if (new_page) {
if (new_page == old_page)
/* cow happened, notify before releasing old_page */
mmu_notifier_invalidate_page(mm, address);
page_cache_release(new_page);
}
if (mmun_called)
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
if (old_page) {
/*
* Don't let another task, with possibly unlocked vma,

6
mm/mmu_notifier.c
View file

@ -137,12 +137,6 @@ void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address,
hlist_for_each_entry_rcu(mn, n, &mm->mmu_notifier_mm->list, hlist) {
if (mn->ops->change_pte)
mn->ops->change_pte(mn, mm, address, pte);
/*
* Some drivers don't have change_pte,
* so we must call invalidate_page in that case.
*/
else if (mn->ops->invalidate_page)
mn->ops->invalidate_page(mn, mm, address);
}
srcu_read_unlock(&srcu, id);
}