ARM: Update page fault handling for new OOM techniques

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 14 insertions, 33 deletions

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 1bb38712c86b..501304f7e30c 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -223,37 +223,18 @@ good_area:
                 goto out;
 
         /*
-         * If for any reason at all we couldn't handle
-         * the fault, make sure we exit gracefully rather
-         * than endlessly redo the fault.
+         * If for any reason at all we couldn't handle the fault, make
+         * sure we exit gracefully rather than endlessly redo the fault.
          */
-survive:
         fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, (fsr & FSR_WRITE) ? FAULT_FLAG_WRITE : 0);
-        if (unlikely(fault & VM_FAULT_ERROR)) {
-                if (fault & VM_FAULT_OOM)
-                        goto out_of_memory;
-                else if (fault & VM_FAULT_SIGBUS)
-                        return fault;
-                BUG();
-        }
+        if (unlikely(fault & VM_FAULT_ERROR))
+                return fault;
         if (fault & VM_FAULT_MAJOR)
                 tsk->maj_flt++;
         else
                 tsk->min_flt++;
         return fault;
 
-out_of_memory:
-        if (!is_global_init(tsk))
-                goto out;
-
-        /*
-         * If we are out of memory for pid1, sleep for a while and retry
-         */
-        up_read(&mm->mmap_sem);
-        yield();
-        down_read(&mm->mmap_sem);
-        goto survive;
-
 check_stack:
         if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
                 goto good_area;
@@ -301,6 +282,16 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
         if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
                 return 0;
 
+        if (fault & VM_FAULT_OOM) {
+                /*
+                 * We ran out of memory, call the OOM killer, and return to
+                 * userspace (which will retry the fault, or kill us if we
+                 * got oom-killed)
+                 */
+                pagefault_out_of_memory();
+                return 0;
+        }
+
         /*
          * If we are in kernel mode at this point, we
          * have no context to handle this fault with.
@@ -308,16 +299,6 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
         if (!user_mode(regs))
                 goto no_context;
 
-        if (fault & VM_FAULT_OOM) {
-                /*
-                 * We ran out of memory, or some other thing
-                 * happened to us that made us unable to handle
-                 * the page fault gracefully.
-                 */
-                printk("VM: killing process %s\n", tsk->comm);
-                do_group_exit(SIGKILL);
-                return 0;
-        }
         if (fault & VM_FAULT_SIGBUS) {
                 /*
                  * We had some memory, but were unable to