Re: [PATCH 20/40] autonuma: alloc/free/init mm_autonuma

From: Rik van Riel
Date: Sun Jul 01 2012 - 11:34:04 EST


On 06/28/2012 08:56 AM, Andrea Arcangeli wrote:

diff --git a/kernel/fork.c b/kernel/fork.c
index 0adbe09..3e5a0d9 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -527,6 +527,8 @@ static void mm_init_aio(struct mm_struct *mm)

static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p)
{
+ if (unlikely(alloc_mm_autonuma(mm)))
+ goto out_free_mm;
atomic_set(&mm->mm_users, 1);
atomic_set(&mm->mm_count, 1);
init_rwsem(&mm->mmap_sem);

I wonder if it would be possible to defer the allocation
of the mm_autonuma struct to knuma_scand, so short lived
processes never have to allocate and free the mm_autonuma
structure.

That way we only have a function call at exit time, and
the branch inside kfree that checks for a null pointer.

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