From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <20070306013815.951032000@taijtu.programming.kicks-ass.net> Date: Tue, 06 Mar 2007 02:38:15 +0100 From: Peter Zijlstra Subject: [RFC][PATCH 0/5] Lockless vma lookups Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org Cc: Christoph Lameter , "Paul E. McKenney" , Nick Piggin , Ingo Molnar , Peter Zijlstra List-ID: mmap_sem is a scalability problem on LargeSMP due to cacheline bouncing and -rt due to is RW nature. The following (rough) patches implement an alternative approach to handling vmas. The RB-tree is discarted in favour of an B+tree like structure because RB-tree rotations are RCU unfriendly and the in-place nodes as used don't help. This allows for RCU lookups of vmas, furthermore they are pinned using a reference count. Modifiers of the vma structure will have to wait till it drops. The code as presented is nowhere near done; but it boots to a full KDE desktop on my i386-up laptop and reached user-space and compiles a kernel on x86_64-smp (its having trouble starting a fancy X desktop though). I'm posting this as a request for comments on the general direction. Post early, avoid isolation, blabla ;-) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org