On Mon, 8 Oct 2012 12:42:34 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Mon, 10 Sep 2012 13:55:15 +0200 > Michal Hocko <mhocko@xxxxxxx> wrote: > > > > >OK. Thanks for the clarification. The main question remains, though. Is > > > >this worth for memblock_is_memory? > > > > > > There are many call sites need to call pfn_valid, how can you guarantee all > > > the addrs are between memblock_start_of_DRAM() and memblock_end_of_DRAM(), > > > if not can this reduce possible overhead ? > > > > That was my question. I hoped for an answer in the patch description. I > > am really not familiar with unicore32 which is the only user now. > > > > > I add unlikely which means that this will not happen frequently. :-) > > > > unlikely doesn't help much in this case. You would be doing the test for > > every pfn_valid invocation anyway. So the main question is. Do you want > > to optimize for something that doesn't happen often when it adds a cost > > (not a big one but still) for the more probable cases? > > I would say yes if we clearly see that the exceptional case really pays > > off. Nothing in the changelog convinces me about that. > > I don't believe Michal's questions have been resolved yet, so I'll keep > this patch on hold for now. ETIMEDOUT. I'll drop the patch. Please resend if you think it's still needed and if these questions can be addressed. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>