From: Russell King Date: Sat, 21 Apr 2007 09:16:48 +0000 (+0100) Subject: [ARM] mm 3: separate out supersection mappings, avoid for <4GB X-Git-Tag: v2.6.22-rc1~1009^2~9 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4a56c1e41f19393577bdd5c774c289c199b7269d;p=pandora-kernel.git [ARM] mm 3: separate out supersection mappings, avoid for <4GB Catalin Marinas at ARM Ltd says: > The CPU architects in ARM intended supersections only as a way to map > addresses >= 4GB. Supersections are not mandated by the architecture > and there is no easy way to detect their hardware support at run-time > (other than checking for a specific core). From the analysis done in > ARM, there wasn't a clear performance gain by using supersections > rather than sections (no significant improvement in the TLB misses). Therefore, we should avoid using supersections unless there's a real need (iow, we're mapping addresses >= 4GB). This means that we can simplify create_mapping() a bit since we will only use supersection mappings for addresses >= 4GB, which means that the physical, virtual and length must be multiples of the supersection mapping size. Signed-off-by: Russell King --- Reading git-diff-tree failed