[v7] move per-vma lock into vm_area_struct

[PATCH v7 05/17] mm: mark vmas detached upon exit

Posted by Suren Baghdasaryan 1 year, 1 month ago

When exit_mmap() removes vmas belonging to an exiting task, it does not
mark them as detached since they can't be reached by other tasks and they
will be freed shortly. Once we introduce vma reuse, all vmas will have to
be in detached state before they are freed to ensure vma when reused is
in a consistent state. Add missing vma_mark_detached() before freeing the
vma.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 mm/vma.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/vma.c b/mm/vma.c
index ce113dd8c471..4a3deb6f9662 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -413,9 +413,10 @@ void remove_vma(struct vm_area_struct *vma, bool unreachable)
 	if (vma->vm_file)
 		fput(vma->vm_file);
 	mpol_put(vma_policy(vma));
-	if (unreachable)
+	if (unreachable) {
+		vma_mark_detached(vma);
 		__vm_area_free(vma);
-	else
+	} else
 		vm_area_free(vma);
 }
 
-- 
2.47.1.613.gc27f4b7a9f-goog

Re: [PATCH v7 05/17] mm: mark vmas detached upon exit

Posted by Vlastimil Babka 1 year, 1 month ago

On 12/26/24 18:06, Suren Baghdasaryan wrote:
> When exit_mmap() removes vmas belonging to an exiting task, it does not
> mark them as detached since they can't be reached by other tasks and they
> will be freed shortly. Once we introduce vma reuse, all vmas will have to
> be in detached state before they are freed to ensure vma when reused is
> in a consistent state. Add missing vma_mark_detached() before freeing the
> vma.
> 
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

> ---
>  mm/vma.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/vma.c b/mm/vma.c
> index ce113dd8c471..4a3deb6f9662 100644
> --- a/mm/vma.c
> +++ b/mm/vma.c
> @@ -413,9 +413,10 @@ void remove_vma(struct vm_area_struct *vma, bool unreachable)
>  	if (vma->vm_file)
>  		fput(vma->vm_file);
>  	mpol_put(vma_policy(vma));
> -	if (unreachable)
> +	if (unreachable) {
> +		vma_mark_detached(vma);
>  		__vm_area_free(vma);
> -	else
> +	} else
>  		vm_area_free(vma);

Nit: per style this should be { } too now.

>  }
>

Re: [PATCH v7 05/17] mm: mark vmas detached upon exit

Posted by Suren Baghdasaryan 1 year, 1 month ago

On Tue, Jan 7, 2025 at 9:08 AM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> On 12/26/24 18:06, Suren Baghdasaryan wrote:
> > When exit_mmap() removes vmas belonging to an exiting task, it does not
> > mark them as detached since they can't be reached by other tasks and they
> > will be freed shortly. Once we introduce vma reuse, all vmas will have to
> > be in detached state before they are freed to ensure vma when reused is
> > in a consistent state. Add missing vma_mark_detached() before freeing the
> > vma.
> >
> > Signed-off-by: Suren Baghdasaryan <surenb@google.com>
>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
>
> > ---
> >  mm/vma.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/mm/vma.c b/mm/vma.c
> > index ce113dd8c471..4a3deb6f9662 100644
> > --- a/mm/vma.c
> > +++ b/mm/vma.c
> > @@ -413,9 +413,10 @@ void remove_vma(struct vm_area_struct *vma, bool unreachable)
> >       if (vma->vm_file)
> >               fput(vma->vm_file);
> >       mpol_put(vma_policy(vma));
> > -     if (unreachable)
> > +     if (unreachable) {
> > +             vma_mark_detached(vma);
> >               __vm_area_free(vma);
> > -     else
> > +     } else
> >               vm_area_free(vma);
>
> Nit: per style this should be { } too now.

Thanks. Will fix it in the next version since I have to respin the
series anyway.

>
> >  }
> >
>