RE: [Xen-merge] arch/i386/mach-xen/mm/highmem.c indentical

["Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>]

> arch/i386/mach-xen/mm/highmem.c is another one to remove it seems?

I've actually got a patch sitting in my tree that touches this file, and
is important for making kmap (>900MB) work well on Xen. I haven't
checked it in because I don't totally like the approach of introducing
"kset_pte_at", though we clearly need something checked in because it's
a huge win on some benchmarks.

The extra optimization in highmem.c is to fold the flush into the
update_va_mapping (which is quite a bit faster than set_pte).

Ian

diff -r e9b950192ba6 linux-2.6-xen-sparse/arch/xen/i386/mm/highmem.c
--- a/linux-2.6-xen-sparse/arch/xen/i386/mm/highmem.c   Wed Aug  3
21:17:17 2005
+++ b/linux-2.6-xen-sparse/arch/xen/i386/mm/highmem.c   Thu Aug  4
19:07:42 2005
@@ -41,8 +41,17 @@
        if (!pte_none(*(kmap_pte-idx)))
                BUG();
 #endif
-       set_pte(kmap_pte-idx, mk_pte(page, prot));
-       __flush_tlb_one(vaddr);
+
+       /* Optimize by using linear mapping */
+       if (HYPERVISOR_update_va_mapping(
+               vaddr,
+               mk_pte(page, prot),
+               UVMF_TLB_FLUSH ) )
+       {
+               /* just in case this isn't mapped in to the PGD */
+               set_pte( kmap_pte-idx, mk_pte(page, prot));     
+               __flush_tlb_one(vaddr);
+       }
 
        return (void*) vaddr;
 }
diff -r e9b950192ba6
linux-2.6-xen-sparse/include/asm-xen/asm-i386/pgtable-2level.h
--- a/linux-2.6-xen-sparse/include/asm-xen/asm-i386/pgtable-2level.h
Wed Aug  3 21:17:17 2005
+++ b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/pgtable-2level.h
Thu Aug  4 19:07:42 2005
@@ -16,6 +16,18 @@
 #define set_pte(pteptr, pteval) (*(pteptr) = pteval)
 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
 #define set_pte_atomic(pteptr, pteval) set_pte(pteptr,pteval)
+
+#define kset_pte_at(addr,ptep,pteval) ({
\
+       if (HYPERVISOR_update_va_mapping(
\
+                (addr),
\
+                (pteval), 0 ) )
\
+        {
\
+                /* just in case this isn't mapped in to the PGD */
\
+                set_pte( (ptep), (pteval));
\
+       }
\
+})
+
+
 
 #ifndef CONFIG_XEN_SHADOW_MODE
 #define set_pmd(pmdptr, pmdval) xen_l2_entry_update((pmdptr), (pmdval))
diff -r e9b950192ba6 linux-2.6-xen-sparse/mm/highmem.c
--- a/linux-2.6-xen-sparse/mm/highmem.c Wed Aug  3 21:17:17 2005
+++ b/linux-2.6-xen-sparse/mm/highmem.c Thu Aug  4 19:07:42 2005
@@ -139,7 +139,7 @@
                }
        }
        vaddr = PKMAP_ADDR(last_pkmap_nr);
-       set_pte_at(&init_mm, vaddr,
+       kset_pte_at(vaddr,
                   &(pkmap_page_table[last_pkmap_nr]), mk_pte(page,
kmap_prot));
 
        pkmap_count[last_pkmap_nr] = 1;

diff -u mm/vmalloc.c mm/vmalloc.c.orig
--- mm/vmalloc.c        2005-06-17 20:48:29.000000000 +0100
+++ mm/vmalloc.c.orig   2005-08-09 11:11:56.120999000 +0100
@@ -96,7 +96,7 @@
                WARN_ON(!pte_none(*pte));
                if (!page)
                        return -ENOMEM;
-               set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
+               kset_pte_at(addr, pte, mk_pte(page, prot));
                (*pages)++;
        } while (pte++, addr += PAGE_SIZE, addr != end);
        return 0;

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