On Thu, 12 Jul 2018 16:37:26 -0400 Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> wrote:
> When struct pages are allocated for sparse-vmemmap VA layout, we first
> try to allocate one large buffer, and than if that fails allocate struct
> pages for each section as we go.
>
> The code that allocates buffer is uses global variables and is spread
> across several call sites.
>
> Cleanup the code by introducing three functions to handle the global
> buffer:
>
> sparse_buffer_init() initialize the buffer
> sparse_buffer_fini() free the remaining part of the buffer
> sparse_buffer_alloc() alloc from the buffer, and if buffer is empty
> return NULL
>
> Define these functions in sparse.c instead of sparse-vmemmap.c because
> later we will use them for non-vmemmap sparse allocations as well.
>
> ...
>
> +void * __meminit sparse_buffer_alloc(unsigned long size)
> +{
> + void *ptr = NULL;
> +
> + if (sparsemap_buf) {
> + ptr = (void *)ALIGN((unsigned long)sparsemap_buf, size);
> + if (ptr + size > sparsemap_buf_end)
> + ptr = NULL;
> + else
> + sparsemap_buf = ptr + size;
> + }
> + return ptr;
> +}
tweak...
diff -puN mm/sparse.c~mm-sparse-abstract-sparse-buffer-allocations-fix mm/sparse.c
--- a/mm/sparse.c~mm-sparse-abstract-sparse-buffer-allocations-fix
+++ a/mm/sparse.c
@@ -491,7 +491,7 @@ void * __meminit sparse_buffer_alloc(uns
void *ptr = NULL;
if (sparsemap_buf) {
- ptr = (void *)ALIGN((unsigned long)sparsemap_buf, size);
+ ptr = PTR_ALIGN(sparsemap_buf, size);
if (ptr + size > sparsemap_buf_end)
ptr = NULL;
else
