From: Zachary Amsden Date: Wed, 2 May 2007 17:27:19 +0000 (+0200) Subject: [PATCH] i386: pte clear optimization X-Git-Tag: v2.6.22-rc1~1011^2~38 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c2c1accd4b2f9c82fb89d40611c7f581948db255;p=pandora-kernel.git [PATCH] i386: pte clear optimization When exiting from an address space, no special hypervisor notification of page table updates needs to occur; direct page table hypervisors, such as Xen, switch to another address space first (init_mm) and unprotects the page tables to avoid the cost of trapping to the hypervisor for each pte_clear. Shadow mode hypervisors, such as VMI and lhype don't need to do the extra work of calling through paravirt-ops, and can just directly clear the page table entries without notifiying the hypervisor, since all the page tables are about to be freed. So introduce native_pte_clear functions which bypass any paravirt-ops notification. This results in a significant performance win for VMI and removes some indirect calls from zap_pte_range. Note the 3-level paging already had a native_pte_clear function, thus demanding argument conformance and extra args for the 2-level definition. Signed-off-by: Zachary Amsden Signed-off-by: Andrew Morton Signed-off-by: Andi Kleen --- Reading git-diff-tree failed