On Tue, Sep 24, 2013 at 06:05:03PM +0800, Zhang Yanfei wrote:
> +/* Allocation direction */
> +enum {
> + MEMBLOCK_DIRECTION_TOP_DOWN,
> + MEMBLOCK_DIRECTION_BOTTOM_UP,
> + NR_MEMLBOCK_DIRECTIONS
> +};
> +
> struct memblock_region {
> phys_addr_t base;
> phys_addr_t size;
> @@ -35,6 +42,7 @@ struct memblock_type {
> };
>
> struct memblock {
> + int current_direction; /* current allocation direction */
Just use boolean bottom_up here too? No need for the constants.
> @@ -20,6 +20,8 @@
> #include <linux/seq_file.h>
> #include <linux/memblock.h>
>
> +#include <asm-generic/sections.h>
> +
Why is the above added by this patch?
> /**
> + * __memblock_find_range - find free area utility
> + * @start: start of candidate range
> + * @end: end of candidate range, can be %MEMBLOCK_ALLOC_{ANYWHERE|ACCESSIBLE}
> + * @size: size of free area to find
> + * @align: alignment of free area to find
> + * @nid: nid of the free area to find, %MAX_NUMNODES for any node
> + *
> + * Utility called from memblock_find_in_range_node(), find free area
> bottom-up.
> + *
> + * RETURNS:
> + * Found address on success, %0 on failure.
I don't think we prefix numeric literals with %.
...
> @@ -127,6 +162,10 @@ __memblock_find_range_rev(phys_addr_t start, phys_addr_t
> end,
> *
> * Find @size free area aligned to @align in the specified range and node.
> *
> + * When allocation direction is bottom-up, the @start should be greater
> + * than the end of the kernel image. Otherwise, it will be trimmed. And also,
> + * if bottom-up allocation failed, will try to allocate memory top-down.
It'd be nice to explain that bottom-up allocation is limited to above
kernel image and what it's used for here.
> + *
> * RETURNS:
> * Found address on success, %0 on failure.
> */
> @@ -134,6 +173,8 @@ phys_addr_t __init_memblock
> memblock_find_in_range_node(phys_addr_t start,
> phys_addr_t end, phys_addr_t size,
> phys_addr_t align, int nid)
> {
> + int ret;
> +
> /* pump up @end */
> if (end == MEMBLOCK_ALLOC_ACCESSIBLE)
> end = memblock.current_limit;
> @@ -142,6 +183,28 @@ phys_addr_t __init_memblock
> memblock_find_in_range_node(phys_addr_t start,
> start = max_t(phys_addr_t, start, PAGE_SIZE);
> end = max(start, end);
>
> + if (memblock_bottom_up()) {
> + phys_addr_t bottom_up_start;
> +
> + /* make sure we will allocate above the kernel */
> + bottom_up_start = max_t(phys_addr_t, start, __pa_symbol(_end));
> +
> + /* ok, try bottom-up allocation first */
> + ret = __memblock_find_range(bottom_up_start, end,
> + size, align, nid);
> + if (ret)
> + return ret;
> +
> + /*
> + * we always limit bottom-up allocation above the kernel,
> + * but top-down allocation doesn't have the limit, so
> + * retrying top-down allocation may succeed when bottom-up
> + * allocation failed.
> + */
> + pr_warn("memblock: Failed to allocate memory in bottom up "
> + "direction. Now try top down direction.\n");
Maybe just print warning only on the first failure?
Otherwise, looks good to me.
Thanks.
--
tejun
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