On Thu, Mar 21, 2019 at 05:45:12PM -0400, Waiman Long wrote: > If the freeing queue has many objects, freeing all of them consecutively > may cause soft lockup especially on a debug kernel. So kmem_free_up_q() > is modified to call cond_resched() if running in the process context. > > Signed-off-by: Waiman Long <[email protected]> > --- > mm/slab_common.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index dba20b4208f1..633a1d0f6d20 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -1622,11 +1622,14 @@ EXPORT_SYMBOL_GPL(kmem_free_q_add); > * kmem_free_up_q - free all the objects in the freeing queue > * @head: freeing queue head > * > - * Free all the objects in the freeing queue. > + * Free all the objects in the freeing queue. The caller cannot hold any > + * non-sleeping locks. > */ > void kmem_free_up_q(struct kmem_free_q_head *head) > { > struct kmem_free_q_node *node, *next; > + bool do_resched = !in_irq(); > + int cnt = 0; > > for (node = head->first; node; node = next) { > next = node->next; > @@ -1634,6 +1637,12 @@ void kmem_free_up_q(struct kmem_free_q_head *head) > kmem_cache_free(node->cachep, node); > else > kfree(node); > + /* > + * Call cond_resched() every 256 objects freed when in > + * process context. > + */ > + if (do_resched && !(++cnt & 0xff)) > + cond_resched();
Why not just: cond_resched() ? > } > } > EXPORT_SYMBOL_GPL(kmem_free_up_q); > -- > 2.18.1 >
