From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Date: Wed, 12 Jan 2005 05:59:26 +0000 Subject: Re: page table lock patch V15 [0/7]: overview Message-Id: <41E4BCBE.2010001@yahoo.com.au> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Lameter Cc: torvalds@osdl.org, Andi Kleen , Hugh Dickins , akpm@osdl.org, linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, Benjamin Herrenschmidt Christoph Lameter wrote: > Changes from V14->V15 of this patch: Hi, I wonder what everyone thinks about moving forward with these patches? Has it been decided that they'll be merged soon? Christoph has been working fairly hard on them, but there hasn't been a lot of feedback. And for those few people who have looked at my patches for page table lock removal, is there is any preference to one implementation or the other? It is probably fair to say that my patches are more comprehensive (in terms of ptl removal, ie. the complete removal**), and can allow architectures to be more flexible in their page table synchronisation methods. However, Christoph's are simpler and probably more widely tested and reviewed at this stage, and more polished. Christoph's implementation probably also covers the most pressing performance cases. On the other hand, my patches *do* allow for the use of a spin-locked synchronisation implementation, which is probably closer to the current code than Christoph's spin-locked pte_cmpxchg fallback in terms of changes to locking semantics. [** Aside, I didn't see a very significant improvement in mm/rmap.c functions from ptl removal. Mostly I think due to contention on mapping->i_mmap_lock (I didn't test anonymous pages, they may have a better yield)]