On Mar 23, 2010, at 6:45 PM, Linus Torvalds wrote: > > > On Tue, 23 Mar 2010, Ingo Molnar wrote: >> >> It shows a very brutal amount of page fault invoked mmap_sem spinning >> overhead. > > Isn't this already fixed? It's the same old "x86-64 rwsemaphores are using > the shit-for-brains generic version" thing, and it's fixed by > > 1838ef1 x86-64, rwsem: 64-bit xadd rwsem implementation > 5d0b723 x86: clean up rwsem type system > 59c33fa x86-32: clean up rwsem inline asm statements > > NOTE! None of those are in 2.6.33 - they were merged afterwards. But they > are in 2.6.34-rc1 (and obviously current -git). So Anton would have to > compile his own kernel to test his load. Thanks for info, I will try it now. > We could mark them as stable material if the load in question is a real > load rather than just a test-case. On one of the random page-fault > benchmarks the rwsem fix was something like a 400% performance > improvement, and it was apparently visible in real life on some crazy SGI > "initialize huge heap concurrently on lots of threads" load. It is not just a test-case, it is real-life code. With real-life problems on 2.6.32 and later :) Anton. -- 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