[Xen-devel] [PATCH 05 of 12] blktap2: reduce TLB flush scope

[Daniel Stodden <daniel.stodden@xxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1244107977 -3600
# Node ID 908662be11ba4e0b92f43097caf7625ef84bf6d9
# Parent  e6bffb2fc52314d542721c60c65cbb2a7779b4c9
blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

To linux-2.6-pvops:
 * Stripped arch/i386/mm/hypervisor.c exports
 * Stripped xen_invlpg_all(kvaddr) use on CONFIG_X86

Signed-off-by: Daniel Stodden <daniel.stodden@xxxxxxxxxx>

diff -r e6bffb2fc523 -r 908662be11ba drivers/xen/blktap/device.c
--- a/drivers/xen/blktap/device.c       Thu Jun 04 10:32:34 2009 +0100
+++ b/drivers/xen/blktap/device.c       Thu Jun 04 10:32:57 2009 +0100
@@ -197,6 +197,12 @@
                                   PAGE_SIZE, blktap_umap_uaddr_fn, mm);
 }
 
+static inline void
+flush_tlb_kernel_page(unsigned long kvaddr)
+{
+       flush_tlb_kernel_range(kvaddr, kvaddr + PAGE_SIZE);
+}
+
 static void
 blktap_device_end_dequeued_request(struct blktap_device *dev,
                                   struct request *req, int error)
@@ -326,7 +332,7 @@
                if (request->handles[i].kernel == INVALID_GRANT_HANDLE) {
                        kvaddr = request_to_kaddr(request, i);
                        blktap_umap_uaddr(&init_mm, kvaddr);
-                       flush_tlb_kernel_range(kvaddr, kvaddr + PAGE_SIZE);
+                       flush_tlb_kernel_page(kvaddr);
                        set_phys_to_machine(__pa(kvaddr) >> PAGE_SHIFT,
                                            INVALID_P2M_ENTRY);
                }
@@ -561,9 +567,9 @@
 
        pte = mk_pte(page, ring->vma->vm_page_prot);
        blktap_map_uaddr(ring->vma->vm_mm, uvaddr, pte_mkwrite(pte));
-       flush_tlb_mm(ring->vma->vm_mm);
+       flush_tlb_page(ring->vma, uvaddr);
        blktap_map_uaddr(&init_mm, kvaddr, mk_pte(page, PAGE_KERNEL));
-       flush_tlb_kernel_range(kvaddr, kvaddr + PAGE_SIZE);
+       flush_tlb_kernel_page(kvaddr);
 
        set_phys_to_machine(__pa(kvaddr) >> PAGE_SHIFT, pte_mfn(pte));
        request->handles[seg].kernel = INVALID_GRANT_HANDLE;

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