summaryrefslogtreecommitdiff
path: root/include/asm-x86/pgtable.h
diff options
context:
space:
mode:
authorJeremy Fitzhardinge <jeremy@goop.org>2008-01-30 15:34:11 +0300
committerIngo Molnar <mingo@elte.hu>2008-01-30 15:34:11 +0300
commitfa28ba21cec24d3fa1279bcae7e5d5ff6224635a (patch)
treedda47a7faa85428753691a50f49b0404f78ea0ec /include/asm-x86/pgtable.h
parentf212ec4b7b4d84290f12c9c0416cdea283bf5f40 (diff)
downloadlinux-fa28ba21cec24d3fa1279bcae7e5d5ff6224635a.tar.xz
x86: defer cr3 reload when doing pud_clear()
PAE mode requires that we reload cr3 in order to guarantee that changes to the pgd will be noticed by the processor. This means that in principle pud_clear needs to reload cr3 every time. However, because reloading cr3 implies a tlb flush, we want to avoid it where possible. pud_clear() is only used in a couple of places: - in free_pmd_range(), when pulling down a range of process address space, and - huge_pmd_unshare() In both cases, the calling code will do a a tlb flush anyway, so there's no need to do it within pud_clear(). In free_pmd_range(), the pud_clear is immediately followed by pmd_free_tlb(); we can hook that to make the mmu_gather do an unconditional full flush to make sure cr3 gets reloaded. In huge_pmd_unshare, it is followed by flush_tlb_range, which always results in a full cr3-reload tlb flush. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: William Irwin <wli@holomorphy.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/asm-x86/pgtable.h')
0 files changed, 0 insertions, 0 deletions