From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from wpaz21.hot.corp.google.com (wpaz21.hot.corp.google.com [172.24.198.85]) by smtp-out.google.com with ESMTP id mB2JUSpO004361 for ; Tue, 2 Dec 2008 11:30:29 -0800 Received: from gxk11 (gxk11.prod.google.com [10.202.11.11]) by wpaz21.hot.corp.google.com with ESMTP id mB2JT4p6019022 for ; Tue, 2 Dec 2008 11:30:27 -0800 Received: by gxk11 with SMTP id 11so618213gxk.13 for ; Tue, 02 Dec 2008 11:30:26 -0800 (PST) MIME-Version: 1.0 Date: Tue, 2 Dec 2008 11:30:25 -0800 Message-ID: <604427e00812021130t1aad58a8j7474258ae33e15a4@mail.gmail.com> Subject: [PATCH][V6]make get_user_pages interruptible From: Ying Han Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org, Andrew Morton , Lee Schermerhorn , Oleg Nesterov , Pekka Enberg , Paul Menage , Rohit Seth List-ID: changelog [v6] replace the sigkill_pending() with fatal_signal_pending() add the check for cases current != tsk From: Ying Han make get_user_pages interruptible The initial implementation of checking TIF_MEMDIE covers the cases of OOM killing. If the process has been OOM killed, the TIF_MEMDIE is set and it return immediately. This patch includes: 1. add the case that the SIGKILL is sent by user processes. The process can try to get_user_pages() unlimited memory even if a user process has sent a SIGKILL to it(maybe a monitor find the process exceed its memory limit and try to kill it). In the old implementation, the SIGKILL won't be handled until the get_user_pages() returns. 2. change the return value to be ERESTARTSYS. It makes no sense to return ENOMEM if the get_user_pages returned by getting a SIGKILL signal. Considering the general convention for a system call interrupted by a signal is ERESTARTNOSYS, so the current return value is consistant to that. Signed-off-by: Paul Menage Signed-off-by: Ying Han mm/memory.c | 13 ++- diff --git a/mm/memory.c b/mm/memory.c index 164951c..049a4f1 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1218,12 +1218,15 @@ int __get_user_pages(struct task_struct *tsk, struct m struct page *page; /* - * If tsk is ooming, cut off its access to large memory - * allocations. It has a pending SIGKILL, but it can't - * be processed until returning to user space. + * If we have a pending SIGKILL, don't keep + * allocating memory. We check both current + * and tsk to cover the cases where current + * is allocating pages on behalf of tsk. */ - if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE))) - return i ? i : -ENOMEM; + if (unlikely(fatal_signal_pending(current) || + ((current != tsk) && + fatal_signal_pending(tsk)))) + return i ? i : -ERESTARTSYS; if (write) foll_flags |= FOLL_WRITE; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org