On 03/30/2017 04:48 PM, Andrey Ryabinin wrote: > On 03/30/2017 03:00 PM, Thomas Hellstrom wrote: > >>> >>> if (unlikely(nr_lazy > lazy_max_pages())) >>> - try_purge_vmap_area_lazy(); >> >> Perhaps a slight optimization would be to schedule work iff >> !mutex_locked(&vmap_purge_lock) below? >> > > Makes sense, we don't need to spawn workers if we already purging. > > > > From: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> > Subject: mm/vmalloc: allow to call vfree() in atomic context fix > > Don't spawn worker if we already purging. > > Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> > --- > mm/vmalloc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index ea1b4ab..88168b8 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -737,7 +737,8 @@ static void free_vmap_area_noflush(struct vmap_area *va) > /* After this point, we may free va at any time */ > llist_add(&va->purge_list, &vmap_purge_list); > > - if (unlikely(nr_lazy > lazy_max_pages())) > + if (unlikely(nr_lazy > lazy_max_pages()) && > + !mutex_is_locked(&vmap_purge_lock)) So, isn't this racy? (and do we care?) Vlastimil > schedule_work(&purge_vmap_work); > } > >