Messages in this thread | | | From | Milton Miller <> | Subject | Re: [PATCH 3/3] x86: OLPC: speed up device tree creation during boot (v2) | Date | Fri, 12 Nov 2010 01:48:30 -0600 |
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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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