From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Date: Sat, 28 Aug 2004 00:36:41 +0000 Subject: Re: page fault scalability patch final : i386 tested, x86_64 Message-Id: <20040827173641.5cfb79f6.akpm@osdl.org> List-Id: References: <20040815165827.0c0c8844.davem@redhat.com> <20040815185644.24ecb247.davem@redhat.com> <20040816143903.GY11200@holomorphy.com> <20040827233602.GB1024@wotan.suse.de> <20040827172337.638275c3.davem@davemloft.net> In-Reply-To: <20040827172337.638275c3.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "David S. Miller" Cc: clameter@sgi.com, ak@suse.de, wli@holomorphy.com, davem@redhat.com, raybry@sgi.com, ak@muc.de, benh@kernel.crashing.org, manfred@colorfullife.com, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, vrajesh@umich.edu, hugh@veritas.com "David S. Miller" wrote: > > On Fri, 27 Aug 2004 17:19:11 -0700 (PDT) > Christoph Lameter wrote: > > > That is still 2^(32+12) = 2^44 = 16TB. > > It's actually: > > 2 ^ (31 + PAGE_SHIFT) > > '31' because atomic_t is 'signed' and PAGE_SHIFT should > be obvious. > > Christoph definitely has a point, this is even more virtual space > than most of the 64-bit platforms even support. (Sparc64 is > 2^43 and I believe ia64 is similar) When can we reasonably expect someone to blow this out of the water? Within the next couple of years, I suspect? 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. > 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?