Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754489AbZDNGUg (ORCPT ); Tue, 14 Apr 2009 02:20:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752260AbZDNGU0 (ORCPT ); Tue, 14 Apr 2009 02:20:26 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:43223 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751300AbZDNGUY (ORCPT ); Tue, 14 Apr 2009 02:20:24 -0400 From: KOSAKI Motohiro To: LKML , Zach Brown , Jens Axboe , linux-api@vger.kernel.org Subject: [RFC][PATCH v3 4/6] aio: Don't inherit aio ring memory at fork Cc: kosaki.motohiro@jp.fujitsu.com, Linus Torvalds , Andrew Morton , Nick Piggin , Andrea Arcangeli , Jeff Moyer , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org In-Reply-To: <20090414151204.C647.A69D9226@jp.fujitsu.com> References: <20090414151204.C647.A69D9226@jp.fujitsu.com> Message-Id: <20090414151924.C653.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50 [ja] Date: Tue, 14 Apr 2009 15:20:20 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2128 Lines: 62 AIO folks, Am I missing anything? =============== Subject: [RFC][PATCH] aio: Don't inherit aio ring memory at fork Currently, mm_struct::ioctx_list member isn't copyed at fork. IOW aio context don't inherit at fork. but only ring memory inherited. that's strange. This patch mark DONTFORK to ring-memory too. In addition, This patch has good side effect. it also fix "get_user_pages() vs fork" problem. I think "man fork" also sould be changed. it only say * The child does not inherit outstanding asynchronous I/O operations from its parent (aio_read(3), aio_write(3)). but aio_context_t (return value of io_setup(2)) also don't inherit in current implementaion. Cc: Jeff Moyer Cc: Zach Brown Cc: Jens Axboe Cc: linux-fsdevel@vger.kernel.org Cc: linux-api@vger.kernel.org, Signed-off-by: KOSAKI Motohiro --- fs/aio.c | 8 ++++++++ 1 file changed, 8 insertions(+) Index: b/fs/aio.c =================================================================== --- a/fs/aio.c 2009-04-12 23:33:59.000000000 +0900 +++ b/fs/aio.c 2009-04-13 02:56:05.000000000 +0900 @@ -106,6 +106,7 @@ static int aio_setup_ring(struct kioctx unsigned nr_events = ctx->max_reqs; unsigned long size; int nr_pages; + int ret; /* Compensate for the ring buffer's head/tail overlap entry */ nr_events += 2; /* 1 is required, 2 for good luck */ @@ -140,6 +141,13 @@ static int aio_setup_ring(struct kioctx return -EAGAIN; } + /* + * aio context doesn't inherit while fork. (see mm_init()) + * Then, aio ring also mark DONTFORK. + */ + ret = sys_madvise(info->mmap_base, info->mmap_size, MADV_DONTFORK); + BUG_ON(ret); + dprintk("mmap address: 0x%08lx\n", info->mmap_base); info->nr_pages = get_user_pages(current, ctx->mm, info->mmap_base, nr_pages, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/