Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935698Ab3DHTH4 (ORCPT ); Mon, 8 Apr 2013 15:07:56 -0400 Received: from mail-pd0-f176.google.com ([209.85.192.176]:63739 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762951Ab3DHTHy (ORCPT ); Mon, 8 Apr 2013 15:07:54 -0400 Date: Mon, 8 Apr 2013 15:07:38 -0400 From: Andrew Shewmaker To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, alan@lxorguk.ukuu.org.uk, simon.jeons@gmail.com, ric.masonn@gmail.com Subject: [PATCH v8 3/3] mm: reinititalise user and admin reserves if memory is added or removed Message-ID: <20130408190738.GC2321@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3198 Lines: 111 This patch alters the admin and user reserves of the previous patches in this series when memory is added or removed. If memory is added and the reserves have been eliminated or increased above the default max, then we'll trust the admin. If memory is removed and there isn't enough free memory, then we need to reset the reserves. Otherwise keep the reserve set by the admin. The reserve reset code is the same as the reserve initialization code. Does this sound reasonable to other people? I figured that hot removal with too large of memory in the reserves was the most important case to get right. I tested hot addition and removal by triggering it via sysfs. The reserves shrunk when they were set high and memory was removed. They were reset higher when memory was added again. --- mm/mmap.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index 8fb9d99..321348b 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -33,6 +33,8 @@ #include #include #include +#include +#include #include #include @@ -3111,3 +3113,64 @@ int __meminit init_admin_reserve(void) return 0; } module_init(init_admin_reserve) + +/* + * Reinititalise user and admin reserves if memory is added or removed. + * + * If memory is added and the reserves have been eliminated or increased above + * the default max, then we'll trust the admin. + * + * If memory is removed and there isn't enough free memory, then we + * need to reset the reserves. + * + * Otherwise keep the reserve set by the admin. + */ +static int reserve_mem_notifier(struct notifier_block *nb, + unsigned long action, void *data) +{ + unsigned long tmp, free_kbytes; + + switch (action) { + case MEM_ONLINE: + tmp = sysctl_user_reserve_kbytes; + if (0 < tmp && tmp < (1UL << 17)) + init_user_reserve(); + + tmp = sysctl_admin_reserve_kbytes; + if (0 < tmp && tmp < (1UL << 13)) + init_admin_reserve(); + + break; + case MEM_OFFLINE: + free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); + + if (sysctl_user_reserve_kbytes > free_kbytes) { + init_user_reserve(); + pr_info("vm.user_reserve_kbytes reset to %lu\n", + sysctl_user_reserve_kbytes); + } + + if (sysctl_admin_reserve_kbytes > free_kbytes) { + init_admin_reserve(); + pr_info("vm.admin_reserve_kbytes reset to %lu\n", + sysctl_admin_reserve_kbytes); + } + break; + default: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block reserve_mem_nb = { + .notifier_call = reserve_mem_notifier, +}; + +int __meminit init_reserve_notifier(void) +{ + if (register_memory_notifier(&reserve_mem_nb)) + printk("Failed registering memory add/remove notifier for admin reserve"); + + return 0; +} +module_init(init_reserve_notifier) -- 1.8.0.1 -- 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/