diff options
author | Haggai Eran <haggaie@mellanox.com> | 2012-10-08 23:33:35 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-09 07:22:58 (GMT) |
commit | 6bdb913f0a70a4dfb7f066fb15e2d6f960701d00 (patch) | |
tree | 9a61960b27bf801794104b8bb8fccee1813f1b4b | |
parent | 2ec74c3ef2d8c58d71e0e00336fb6b891192155a (diff) | |
download | linux-6bdb913f0a70a4dfb7f066fb15e2d6f960701d00.tar.xz |
mm: wrap calls to set_pte_at_notify with invalidate_range_start and invalidate_range_end
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>
-rw-r--r-- | kernel/events/uprobes.c | 5 | ||||
-rw-r--r-- | mm/ksm.c | 21 | ||||
-rw-r--r-- | mm/memory.c | 18 | ||||
-rw-r--r-- | mm/mmu_notifier.c | 6 |
4 files changed, 36 insertions, 14 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 1d9c0a9..98256bc 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -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; } @@ -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; } diff --git a/mm/memory.c b/mm/memory.c index b03a4a2..01ec048 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -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 @@ gotten: 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 @@ gotten: } 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, diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index c297142..479a1e7 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -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); } |