From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Date: Sat, 28 Aug 2004 01:39:40 +0000 Subject: Re: page fault scalability patch final : i386 tested, x86_64 Message-Id: <20040827183940.33b38bc2.akpm@osdl.org> List-Id: References: <20040816143903.GY11200@holomorphy.com> <20040827233602.GB1024@wotan.suse.de> <20040827172337.638275c3.davem@davemloft.net> <20040827173641.5cfb79f6.akpm@osdl.org> <20040828010253.GA50329@muc.de> In-Reply-To: <20040828010253.GA50329@muc.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andi Kleen Cc: davem@davemloft.net, clameter@sgi.com, ak@suse.de, wli@holomorphy.com, davem@redhat.com, raybry@sgi.com, benh@kernel.crashing.org, manfred@colorfullife.com, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, vrajesh@umich.edu, hugh@veritas.com Andi Kleen wrote: > > > When can we reasonably expect someone to blow this out of the water? > > Within the next couple of years, I suspect? > > With 4 level page tables x86-64 will support 47 bits virtual theoretical. > They cannot be used right now because the current x86-64 CPUs have > 40 bits physical max and it is currently even hardcoded to 40bits, > but I planned to drop that in the 4 level patch (in fact I already did) > so that the kernel will in theory support CPUs will more physical memory. > hm. What's the maximum virtual size on power5? > > It does look like we need a new type which is atomic64 on 64-bit and > > atomic32 on 32-bit. That could be used to fix the > > mmaping-the-same-page-4G-times-kills-the-kernel bug too. > > Yep. Good plan. atomic_long_t ? Sounds good. Converting page->_count should be fairly straightforward now too, as it's all done via wrappers. > > > > > and this limit actually > > > mostly comes from the 3-level page table limits. > > > > This reminds me - where's that 4-level pagetable patch got to? > > It exists on my HD, but is not really finished yet. > > I was on vacation and travelling and had some other things to do, so it got > delayed a bit, but I hope to work on it soon again. OK, thanks. There's no rush on this one.