On Thu, 11 Nov 2010 around 21:45:46 -0800, Andres Salomon wrote:
> diff --git a/arch/x86/platform/olpc/olpc_dt.c
> b/arch/x86/platform/olpc/olpc_dt.c
> index b8c8ff9..0ab824d 100644
> --- a/arch/x86/platform/olpc/olpc_dt.c
> +++ b/arch/x86/platform/olpc/olpc_dt.c
> @@ -126,14 +126,31 @@ static unsigned int prom_early_allocated __initdata;
>
> void * __init prom_early_alloc(unsigned long size)
> {
> + static u8 *mem = NULL;
> + static size_t free_mem = 0;
Static variables are implicitly 0 and NULL
> void *res;
>
> - res = alloc_bootmem(size);
> - if (res)
> - memset(res, 0, size);
> -
> - prom_early_allocated += size;
> + if (free_mem < size) {
> + const size_t chunk_size = max(PAGE_SIZE, size);
> +
> + /*
> + * To mimimize the number of allocations, grab at least 4k of
> + * memory (that's an arbitrary choice that matches PAGE_SIZE on
> + * the platforms we care about, and minimizes wasted bootmem)
> + * and hand off chunks of it to callers.
> + */
> + res = mem = alloc_bootmem(chunk_size);
> + if (!res)
> + return NULL;
Oops. If alloc_bootmem fails, we loose mem but don't reset free_mem, so a
later call (possibly for a smaller chunk) may return memory starting
at NULL.
I suggest just assinging res above and then add mem = res inside this if.
Oh, this is alloc_bootmem not alloc_bootmem_nopainc ... should it be?
> + prom_early_allocated += chunk_size;
> + memset(res, 0, chunk_size);
> + free_mem = chunk_size;
> + }
>
> + /* allocate from the local cache */
> + free_mem -= size;
> + res = mem;
> + mem += size;
> return res;
> }
>
milton
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