Re: [PATCH 07/10] bootmem: add free_bootmem_late

Pekka Enberg
2009-11-10T08:06:00Z

FUJITA Tomonori wrote:
> On Mon, 9 Nov 2009 22:21:48 +0200
> Pekka Enberg <penberg@cs.helsinki.fi> wrote:
>
>> On Mon, Nov 9, 2009 at 10:13 PM, Pekka Enberg <penberg@cs.helsinki.fi> wrote:
>>>> for (cursor = start; cursor < end; cursor += BITS_PER_LONG) {
>>>> - unsigned long idx, vec;
>>>> + unsigned long vec;
>>>>
>>>> - idx = cursor - start;
>>>> - vec = ~map[idx / BITS_PER_LONG];
>>>> + if (map) {
>>>> + unsigned long idx = cursor - start;
>>>> + vec = ~map[idx / BITS_PER_LONG];
>>>> + } else {
>>>> + if (end - cursor >= BITS_PER_LONG)
>>>> + vec = ~0UL;
>>> Why do we need the above?
>> OK, I figured that out. I'm not sure why you want to play tricks with
>> "vec" when you could just add a new helper that calls
>> __free_pages_bootmem() for the full contiguous page range.
>
> I'm not sure why Chris did that, but yeah, I think that it's cleaner
> to leave free_all_bootmem_core alone.
>
> There is just one user of free_bootmem_late to free some memory so how
> about the following simple patch instead 7/10?

Looks good to me!

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>

> diff --git a/include/linux/bootmem.h b/include/linux/bootmem.h
> index dd97fb8..b10ec49 100644
> --- a/include/linux/bootmem.h
> +++ b/include/linux/bootmem.h
> @@ -53,6 +53,7 @@ extern void free_bootmem_node(pg_data_t *pgdat,
> unsigned long addr,
> unsigned long size);
> extern void free_bootmem(unsigned long addr, unsigned long size);
> +extern void free_bootmem_late(unsigned long addr, unsigned long size);
>
> /*
> * Flags for reserve_bootmem (also if CONFIG_HAVE_ARCH_BOOTMEM_NODE,
> diff --git a/mm/bootmem.c b/mm/bootmem.c
> index 94ef2e7..b0b393b 100644
> --- a/mm/bootmem.c
> +++ b/mm/bootmem.c
> @@ -196,6 +196,30 @@ static unsigned long __init free_bootmem_pages(unsigned long start,
> return count;
> }
>
> +/*
> + * free_bootmem_late - free bootmem pages directly to page allocator
> + * @addr: starting address of the range
> + * @size: size of the range in bytes
> + *
> + * This is only useful when the bootmem allocator has already been torn
> + * down, but we are still initializing the system. Pages are given directly
> + * to the page allocator, no bootmem metadata is updated because it is gone.
> + */
> +void __init free_bootmem_late(unsigned long addr, unsigned long size)
> +{
> + unsigned long cursor, end;
> +
> + kmemleak_free_part(__va(addr), size);
> +
> + cursor = PFN_UP(addr);
> + end = PFN_DOWN(addr + size);
> +
> + for (; cursor < end; cursor++) {
> + __free_pages_bootmem(pfn_to_page(cursor), 0);
> + totalram_pages++;
> + }
> +}
> +
> static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
> {
> struct page *page;
>
>