Messages in this thread | | | Date | Mon, 22 Sep 2003 18:31:22 +0200 | From | Manfred Spraul <> | Subject | Re: [PATCH] Move slab objects to the end of the real allocation |
| |
Arnd Bergmann wrote:
>Manfred Spraul wrote: > > >> - Do not page-pad allocations that are <= SMP_CACHE_LINE_SIZE. This >> crashes. Right now the limit is hardcoded to 128 bytes, but sooner or >> later an arch will appear with 256 byte cache lines. >> >> > >What made you think that 128 is the current maximum? All s390 machines >have 256 byte cache lines. > > When I wrote "128" I was not aware that this is linked to the cache line size. Initially it was ">128", just as an arbitrary number. I replaced that with "> 116" due to an unrelated change, and that crashed, because the cache line size was set to 128 bytes.
My patch fixes this bug: It replaces the limits with >=116 [avoid wasting too much memory, guarantee that there is a cache for the off-slab control structures] and > SMP_CACHE_LINE_SIZE [guarantee that there is a cache for the off-slab control structures].
Right now there are too many patches in Andrew's tree, I'll wait until everything settled down a bit, then I'll resent the cache line size as a one-line patch. Do you want to implement CONFIG_DEBUG_PAGEALLOC immediately? If yes, then I can send you the oneliner immediately. Nothing except CONFIG_DEBUG_PAGEALLOC is affected by the bug.
-- Manfred
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |