ARM: Update page fault handling for new OOM techniques (b42c6344) · Commits · e / devices / android_kernel_fairphone_FP4

arch/arm/mm/fault.c

+14 −33

Original line number	Diff line number	Diff line
		@@ -223,37 +223,18 @@ __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
		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)
		if (unlikely(fault & VM_FAULT_ERROR))
		return fault;
		BUG();
		}
		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