Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=64f60841c096594b8073e408cd9b40d7d08dcfdd
Commit:     64f60841c096594b8073e408cd9b40d7d08dcfdd
Parent:     8603ec81487a5fefbc29611ff0d635b33b6da990
Author:     Jeff Dike <[EMAIL PROTECTED]>
AuthorDate: Sun May 6 14:51:45 2007 -0700
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Mon May 7 12:13:04 2007 -0700

    uml: speed page fault path
    
    Give the page fault code a specialized path.  There is only one page to look
    at, so there's no point in going into the general page table walking code.
    There's only going to be one host operation, so there are no opportunities 
for
    merging.  So, we go straight to the pte we want, figure out what needs 
doing,
    and do it.
    
    While I was in here, I fixed the wart where the address passed to unmap was 
a
    void *, but an unsigned long to map and protect.
    
    This gives me just under 10% on a kernel build.
    
    Signed-off-by: Jeff Dike <[EMAIL PROTECTED]>
    Cc: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 arch/um/include/os.h                  |    2 +-
 arch/um/include/skas/mode_kern_skas.h |    2 +
 arch/um/kernel/skas/tlb.c             |   66 ++++++++++++++++++++++++++++++++-
 arch/um/kernel/tlb.c                  |    4 +-
 arch/um/os-Linux/skas/mem.c           |    4 +-
 5 files changed, 72 insertions(+), 6 deletions(-)

diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index d663809..e11bdcd 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -302,7 +302,7 @@ extern long syscall_stub_data(struct mm_id * mm_idp,
 extern int map(struct mm_id * mm_idp, unsigned long virt,
               unsigned long len, int r, int w, int x, int phys_fd,
               unsigned long long offset, int done, void **data);
-extern int unmap(struct mm_id * mm_idp, void *addr, unsigned long len,
+extern int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
                 int done, void **data);
 extern int protect(struct mm_id * mm_idp, unsigned long addr,
                   unsigned long len, int r, int w, int x, int done,
diff --git a/arch/um/include/skas/mode_kern_skas.h 
b/arch/um/include/skas/mode_kern_skas.h
index 9cd9c6e..8ee6285 100644
--- a/arch/um/include/skas/mode_kern_skas.h
+++ b/arch/um/include/skas/mode_kern_skas.h
@@ -33,6 +33,8 @@ extern unsigned long set_task_sizes_skas(unsigned long 
*task_size_out);
 extern int start_uml_skas(void);
 extern int external_pid_skas(struct task_struct *task);
 extern int thread_pid_skas(struct task_struct *task);
+extern void flush_tlb_page_skas(struct vm_area_struct *vma,
+                               unsigned long address);
 
 #define kmem_end_skas (host_task_size - 1024 * 1024)
 
diff --git a/arch/um/kernel/skas/tlb.c b/arch/um/kernel/skas/tlb.c
index 304a5b0..c43901a 100644
--- a/arch/um/kernel/skas/tlb.c
+++ b/arch/um/kernel/skas/tlb.c
@@ -32,8 +32,7 @@ static int do_ops(union mm_context *mmu, struct host_vm_op 
*ops, int last,
                                  op->u.mmap.offset, finished, flush);
                        break;
                case MUNMAP:
-                       ret = unmap(&mmu->skas.id,
-                                   (void *) op->u.munmap.addr,
+                       ret = unmap(&mmu->skas.id, op->u.munmap.addr,
                                    op->u.munmap.len, finished, flush);
                        break;
                case MPROTECT:
@@ -94,3 +93,66 @@ void force_flush_all_skas(void)
        unsigned long end = proc_mm ? task_size : CONFIG_STUB_START;
         fix_range(current->mm, 0, end, 1);
 }
+
+void flush_tlb_page_skas(struct vm_area_struct *vma, unsigned long address)
+{
+       pgd_t *pgd;
+       pud_t *pud;
+       pmd_t *pmd;
+       pte_t *pte;
+       struct mm_struct *mm = vma->vm_mm;
+       void *flush = NULL;
+       int r, w, x, err = 0;
+       struct mm_id *mm_id;
+
+       pgd = pgd_offset(vma->vm_mm, address);
+       if(!pgd_present(*pgd))
+               goto kill;
+
+       pud = pud_offset(pgd, address);
+       if(!pud_present(*pud))
+               goto kill;
+
+       pmd = pmd_offset(pud, address);
+       if(!pmd_present(*pmd))
+               goto kill;
+
+       pte = pte_offset_kernel(pmd, address);
+
+       r = pte_read(*pte);
+       w = pte_write(*pte);
+       x = pte_exec(*pte);
+       if (!pte_young(*pte)) {
+               r = 0;
+               w = 0;
+       } else if (!pte_dirty(*pte)) {
+               w = 0;
+       }
+
+       mm_id = &mm->context.skas.id;
+       if(pte_newpage(*pte)){
+               if(pte_present(*pte)){
+                       unsigned long long offset;
+                       int fd;
+
+                       fd = phys_mapping(pte_val(*pte) & PAGE_MASK, &offset);
+                       err = map(mm_id, address, PAGE_SIZE, r, w, x, fd,
+                                 offset, 1, &flush);
+               }
+               else err = unmap(mm_id, address, PAGE_SIZE, 1, &flush);
+       }
+       else if(pte_newprot(*pte))
+               err = protect(mm_id, address, PAGE_SIZE, r, w, x, 1, &flush);
+
+       if(err)
+               goto kill;
+
+       *pte = pte_mkuptodate(*pte);
+
+       return;
+
+kill:
+       printk("Failed to flush page for address 0x%lx\n", address);
+       force_sig(SIGKILL, current);
+}
+
diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index e201ccf..00de86e 100644
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -381,7 +381,9 @@ pte_t *addr_pte(struct task_struct *task, unsigned long 
addr)
 void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
 {
        address &= PAGE_MASK;
-       flush_tlb_range(vma, address, address + PAGE_SIZE);
+
+       CHOOSE_MODE(flush_tlb_range(vma, address, address + PAGE_SIZE),
+                   flush_tlb_page_skas(vma, address));
 }
 
 void flush_tlb_all(void)
diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index 6cdfda8..af07907 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -219,8 +219,8 @@ int map(struct mm_id * mm_idp, unsigned long virt, unsigned 
long len,
        return ret;
 }
 
-int unmap(struct mm_id * mm_idp, void *addr, unsigned long len, int done,
-         void **data)
+int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
+         int done, void **data)
 {
        int ret;
 
-
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