On Tue, May 25, 2010 at 10:28:11AM -0500, Christoph Lameter wrote: > On Wed, 26 May 2010, Nick Piggin wrote: > > > You do not understand. There is nothing *preventing* other designs of > > allocators from using higher order allocations. The problem is that > > SLUB is *forced* to use them due to it's limited queueing capabilities. > > SLUBs use of higher order allocation is *optional*. The limited queuing is > advantageous within the framework of SLUB because NUMA locality checks are > simplified and locking is localized to a single page increasing > concurrency. It's not optional if performance sucks without it. People want to have a well performing slab allocator and also not have the downsides of it using higher order allocations. Look at what David said about Google's kernel for a concrete example. > > You keep spinning this as a good thing for SLUB design when it is not. > > It is a good design decision. You have an irrational fear of higher order > allocations. No. > > > The reason that the alien caches made it into SLAB were performance > > > numbers that showed that the design "must" be this way. I prefer a clear > > > maintainable design over some numbers (that invariably show the bias of > > > the tester for certain loads). > > > > I don't really agree. There are a number of other possible ways to > > improve it, including fewer remote freeing queues. > > You disagree with the history of the allocator? I don't agree with you saying that it "must" be that way. There are other ways to improve things there. > > How is it possibly better to instead start from the known suboptimal > > code and make changes to it? What exactly is your concern with > > making incremental changes to SLAB? > > I am not sure why you want me to repeat what I already said. Guess we > should stop this conversation since it is deteriorating. You never answered these questions adequately. These are the 2 most important things because if I can address your concerns with them, then we can go ahead and throw out SLUB and make incremental improvements from there instead. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>