On Fri, Dec 14, 2018 at 10:07:18AM -0800, Roman Gushchin wrote:
> alloc_vmap_area() is allocating memory for the vmap_area, and
> performing the actual lookup of the vm area and vmap_area
> initialization.
>
> This prevents us from using a pre-allocated memory for the map_area
> structure, which can be used in some cases to minimize the number
> of required memory allocations.
>
> Let's keep the memory allocation part in alloc_vmap_area() and
> separate everything else into init_vmap_area().
Oh good, I was considering doing something like this eventually.
> +++ b/mm/vmalloc.c
> @@ -395,16 +395,11 @@ static void purge_vmap_area_lazy(void);
>
> static BLOCKING_NOTIFIER_HEAD(vmap_notify_list);
>
> -/*
> - * Allocate a region of KVA of the specified size and alignment, within the
> - * vstart and vend.
> - */
> -static struct vmap_area *alloc_vmap_area(unsigned long size,
> - unsigned long align,
> - unsigned long vstart, unsigned long vend,
> - int node, gfp_t gfp_mask)
> +static int init_vmap_area(struct vmap_area *va, unsigned long size,
> + unsigned long align, unsigned long vstart,
> + unsigned long vend, int node, gfp_t gfp_mask)
> {
> - struct vmap_area *va;
> +
Why the blank line?
> struct rb_node *n;
> unsigned long addr;
> int purged = 0;
> @@ -416,11 +411,6 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
>
> might_sleep();
>
> - va = kmalloc_node(sizeof(struct vmap_area),
> - gfp_mask & GFP_RECLAIM_MASK, node);
> - if (unlikely(!va))
> - return ERR_PTR(-ENOMEM);
> -
> /*
> * Only scan the relevant parts containing pointers to other objects
> * to avoid false negatives.
> @@ -512,7 +502,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
> BUG_ON(va->va_start < vstart);
> BUG_ON(va->va_end > vend);
>
> - return va;
> + return 0;
>
> overflow:
> spin_unlock(&vmap_area_lock);
> @@ -534,10 +524,38 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
> if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
> pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n",
> size);
> - kfree(va);
> - return ERR_PTR(-EBUSY);
> +
> + return -EBUSY;
> +}
> +
> +/*
> + * Allocate a region of KVA of the specified size and alignment, within the
> + * vstart and vend.
> + */
> +static struct vmap_area *alloc_vmap_area(unsigned long size,
> + unsigned long align,
> + unsigned long vstart,
> + unsigned long vend,
> + int node, gfp_t gfp_mask)
> +{
> + struct vmap_area *va;
> + int ret;
> +
> + va = kmalloc_node(sizeof(struct vmap_area),
> + gfp_mask & GFP_RECLAIM_MASK, node);
> + if (unlikely(!va))
> + return ERR_PTR(-ENOMEM);
> +
> + ret = init_vmap_area(va, size, align, vstart, vend, node, gfp_mask);
> + if (ret) {
> + kfree(va);
> + return ERR_PTR(ret);
> + }
> +
> + return va;
> }
>
> +
Another spurious blank line?
With these two fixed,
Reviewed-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
