From 1c0fe6e3bda0464728c23c8d84aa47567e8b716c Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Tue, 6 Jan 2009 14:38:59 -0800 Subject: mm: invoke oom-killer from page fault Rather than have the pagefault handler kill a process directly if it gets a VM_FAULT_OOM, have it call into the OOM killer. With increasingly sophisticated oom behaviour (cpusets, memory cgroups, oom killing throttling, oom priority adjustment or selective disabling, panic on oom, etc), it's silly to unconditionally kill the faulting process at page fault time. Create a hook for pagefault oom path to call into instead. Only converted x86 and uml so far. [akpm@linux-foundation.org: make __out_of_memory() static] [akpm@linux-foundation.org: fix comment] Signed-off-by: Nick Piggin Cc: Jeff Dike Acked-by: Ingo Molnar Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/kernel/trap.c | 24 ++++++++---------------- 1 file changed, 8 insertions(+), 16 deletions(-) (limited to 'arch/um/kernel') diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index 44e4904..7384d8a 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -64,11 +64,10 @@ good_area: do { int fault; -survive: + fault = handle_mm_fault(mm, vma, address, is_write); if (unlikely(fault & VM_FAULT_ERROR)) { if (fault & VM_FAULT_OOM) { - err = -ENOMEM; goto out_of_memory; } else if (fault & VM_FAULT_SIGBUS) { err = -EACCES; @@ -104,18 +103,14 @@ out: out_nosemaphore: return err; -/* - * We ran out of memory, or some other thing happened to us that made - * us unable to handle the page fault gracefully. - */ out_of_memory: - if (is_global_init(current)) { - up_read(&mm->mmap_sem); - yield(); - down_read(&mm->mmap_sem); - goto survive; - } - goto out; + /* + * We ran out of memory, call the OOM killer, and return the userspace + * (which will retry the fault, or kill us if we got oom-killed). + */ + up_read(&mm->mmap_sem); + pagefault_out_of_memory(); + return 0; } static void bad_segv(struct faultinfo fi, unsigned long ip) @@ -214,9 +209,6 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, si.si_addr = (void __user *)address; current->thread.arch.faultinfo = fi; force_sig_info(SIGBUS, &si, current); - } else if (err == -ENOMEM) { - printk(KERN_INFO "VM: killing process %s\n", current->comm); - do_exit(SIGKILL); } else { BUG_ON(err != -EFAULT); si.si_signo = SIGSEGV; -- cgit v1.1