Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756335AbXI1Mzm (ORCPT ); Fri, 28 Sep 2007 08:55:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753378AbXI1Mze (ORCPT ); Fri, 28 Sep 2007 08:55:34 -0400 Received: from nf-out-0910.google.com ([64.233.182.185]:65340 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752910AbXI1Mze (ORCPT ); Fri, 28 Sep 2007 08:55:34 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=nk518aFySy+IYD7SZRMyz0dxPT9h8gVgNkqYmWAK+bE3+aWI1eSV3TRy+ZI3uFrzHc7cOAkUmAjz0Rv8ecXve2FPHLy57t57wZJyYmtlcAIFMFHnqwYZh9FeYovKVw09WuL+qxM0lBwz4IvnFeFxB/zvhqIAnB2CZgb0ZFOYHwk= Message-ID: Date: Fri, 28 Sep 2007 14:55:30 +0200 From: "=?ISO-8859-1?Q?Daniel_Sp=E5ng?=" To: linux-kernel@vger.kernel.org Subject: Out of memory management in embedded systems MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1491 Lines: 35 Applications with dynamic input and dynamic memory usage have some issues with the current overcommitting kernel. A high memory usage situation eventually results in that a process is killed by the OOM killer. This is especially evident in swapless embedded systems with limited memory and no swap available. Some kind of notification to the application that the available memory is scarce and let the application free up some memory (e.g., by flushing caches), could be used to improve the situation and avoid the OOM killer. I am currently not aware of any general solution to this problem, but I have found some approaches that might (or might not) work: o Turn off overcommit. Results in a waste of memory. o Nokia uses a lowmem security module to signal on predetermined thresholds. Currently available in the -omap tree. But this requires manual tuning of the thresholds. http://www.linuxjournal.com/article/8502 o Using madvise() with MADV_FREE to get the kernel to free mmaped memory, typically application caches, when the kernel needs the memory. o A OOM handler that the application registers with the kernel, and that the kernel executes before the OOM-killer steps in. Does it exist any other solutions to this problem? Daniel - 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/