x86: defer cr3 reload when doing pud_clear()

[safe/jmp/linux-2.6] / include / asm-x86 / pgalloc_32.h

diff --git a/include/asm-x86/pgalloc_32.h b/include/asm-x86/pgalloc_32.h
index 0caa37a..10c2b45 100644 (file)
--- a/include/asm-x86/pgalloc_32.h
+++ b/include/asm-x86/pgalloc_32.h
@@ -74,6 +74,13 @@ static inline void pmd_free(pmd_t *pmd)
 
 static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
 {
+       /* This is called just after the pmd has been detached from
+          the pgd, which requires a full tlb flush to be recognized
+          by the CPU.  Rather than incurring multiple tlb flushes
+          while the address space is being pulled down, make the tlb
+          gathering machinery do a full flush when we're done. */
+       tlb->fullmm = 1;
+
        paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
        tlb_remove_page(tlb, virt_to_page(pmd));
 }