On Fri, 12 Dec 2008 11:48:29 +1100 Paul Mackerras <pau...@samba.org> wrote:
> Andrew Morton writes: > > > > +#if (8 * THREAD_SIZE) > PAGE_SIZE > > > max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); > > > +#else > > > + max_threads = mempages * (PAGE_SIZE / (8 * THREAD_SIZE)); > > > +#endif > > > > The expression you've chosen here can be quite inacccurate, because > > ((PAGE_SIZE / (8 * THREAD_SIZE)) is a small number. The way to > > preserve accuracy is > > The assumption is that THREAD_SIZE is a power of 2, as is PAGE_SIZE. > > I think Yuri should be increasing THREAD_SIZE for the larger page > sizes he's implementing, because we have on-stack arrays whose size > depends on the page size. I suspect that having THREAD_SIZE less than > 1/8 of PAGE_SIZE risks stack overflows, and the better fix is for Yuri > to make sure THREAD_SIZE is at least 1/8 of PAGE_SIZE. (In fact, more > may be needed - someone should work out what fraction is actually > needed.) OK, yes. It's the MAX_BUF_PER_PAGE arrays which will hurt. iirc they nest three-deep on some codepaths. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
