Messages in this thread | | | Date | Thu, 26 Jul 2012 10:48:39 +0530 | From | Srikar Dronamraju <> | Subject | Re: [PATCH 4/4] uprobes: __replace_page() needs munlock_vma_page() |
| |
* Oleg Nesterov <oleg@redhat.com> [2012-07-12 19:10:25]:
> Like do_wp_page(), __replace_page() should do munlock_vma_page() > for the case when the old page still has other !VM_LOCKED mappings. > Unfortunately this needs mm/internal.h. > > Also, move put_page() outside of ptl lock. This doesn't really > matter but looks a bit better. > > Signed-off-by: Oleg Nesterov <oleg@redhat.com>
One thing I wanted to check is, should we mlock the new page, i.e the replacing page. It may not a good idea to mlock the new page because then we can end up adding too many pages to the unevictable list.
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> --- > kernel/events/uprobes.c | 8 ++++++-- > 1 files changed, 6 insertions(+), 2 deletions(-) > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index fc1df43..aeea41b 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -32,6 +32,7 @@ > #include <linux/swap.h> /* try_to_free_swap */ > #include <linux/ptrace.h> /* user_enable_single_step */ > #include <linux/kdebug.h> /* notifier mechanism */ > +#include "../../mm/internal.h" /* munlock_vma_page */ > > #include <linux/uprobes.h> > > @@ -141,7 +142,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr, > pte_t *ptep; > int err; > > - /* freeze PageSwapCache() for try_to_free_swap() below */ > + /* For try_to_free_swap() and munlock_vma_page() below */ > lock_page(page); > > err = -EAGAIN; > @@ -164,9 +165,12 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr, > page_remove_rmap(page); > if (!page_mapped(page)) > try_to_free_swap(page); > - put_page(page); > pte_unmap_unlock(ptep, ptl); > > + if (vma->vm_flags & VM_LOCKED) > + munlock_vma_page(page); > + put_page(page); > + > err = 0; > unlock: > unlock_page(page); > -- > 1.5.5.1 >
| |