Re: [RFC v2 1/3] mm/vmalloc: fix possible exhaustion of vmalloc space caused by vm_map_ram allocator

From: Gioh Kim
Date: Tue Mar 24 2015 - 21:01:54 EST


>
> In current patch I simply put newly allocated block to the tail of a free list,
> thus reduce fragmentation, giving a chance to resolve allocation request using
> older blocks with possible holes left.

It's great.
I think this might be helpful for fragmentation by mix of long-time, short-time mappings.
I do thank you for your work.

>
> Signed-off-by: Roman Pen <r.peniaev@xxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> Acked-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>
> Cc: WANG Chao <chaowang@xxxxxxxxxx>
> Cc: Fabian Frederick <fabf@xxxxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxx>
> Cc: Gioh Kim <gioh.kim@xxxxxxx>
> Cc: Rob Jones <rob.jones@xxxxxxxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> mm/vmalloc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 39c3388..db6bffb 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -837,7 +837,7 @@ static struct vmap_block *new_vmap_block(gfp_t gfp_mask)
>
> vbq = &get_cpu_var(vmap_block_queue);
> spin_lock(&vbq->lock);
> - list_add_rcu(&vb->free_list, &vbq->free);
> + list_add_tail_rcu(&vb->free_list, &vbq->free);
> spin_unlock(&vbq->lock);
> put_cpu_var(vmap_block_queue);
>
>
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