From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754980AbdK1Lci (ORCPT ); Tue, 28 Nov 2017 06:32:38 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:60990 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932182AbdK1Kom (ORCPT ); Tue, 28 Nov 2017 05:44:42 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikulas Patocka , Mike Snitzer Subject: [PATCH 4.14 043/193] dm: allocate struct mapped_device with kvzalloc Date: Tue, 28 Nov 2017 11:24:50 +0100 Message-Id: <20171128100615.408163676@linuxfoundation.org> X-Mailer: git-send-email 2.15.0 In-Reply-To: <20171128100613.638270407@linuxfoundation.org> References: <20171128100613.638270407@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mikulas Patocka commit 856eb0916d181da6d043cc33e03f54d5c5bbe54a upstream. The structure srcu_struct can be very big, its size is proportional to the value CONFIG_NR_CPUS. The Fedora kernel has CONFIG_NR_CPUS 8192, the field io_barrier in the struct mapped_device has 84kB in the debugging kernel and 50kB in the non-debugging kernel. The large size may result in failure of the function kzalloc_node. In order to avoid the allocation failure, we use the function kvzalloc_node, this function falls back to vmalloc if a large contiguous chunk of memory is not available. This patch also moves the field io_barrier to the last position of struct mapped_device - the reason is that on many processor architectures, short memory offsets result in smaller code than long memory offsets - on x86-64 it reduces code size by 320 bytes. Note to stable kernel maintainers - the kernels 4.11 and older don't have the function kvzalloc_node, you can use the function vzalloc_node instead. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-core.h | 3 ++- drivers/md/dm.c | 6 +++--- 2 files changed, 5 insertions(+), 4 deletions(-) --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -29,7 +29,6 @@ struct dm_kobject_holder { * DM targets must _not_ deference a mapped_device to directly access its members! */ struct mapped_device { - struct srcu_struct io_barrier; struct mutex suspend_lock; /* @@ -127,6 +126,8 @@ struct mapped_device { struct blk_mq_tag_set *tag_set; bool use_blk_mq:1; bool init_tio_pdu:1; + + struct srcu_struct io_barrier; }; void dm_init_md_queue(struct mapped_device *md); --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1695,7 +1695,7 @@ static struct mapped_device *alloc_dev(i struct mapped_device *md; void *old_md; - md = kzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id); + md = kvzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id); if (!md) { DMWARN("unable to allocate device, out of memory."); return NULL; @@ -1795,7 +1795,7 @@ bad_io_barrier: bad_minor: module_put(THIS_MODULE); bad_module_get: - kfree(md); + kvfree(md); return NULL; } @@ -1814,7 +1814,7 @@ static void free_dev(struct mapped_devic free_minor(minor); module_put(THIS_MODULE); - kfree(md); + kvfree(md); } static void __bind_mempools(struct mapped_device *md, struct dm_table *t)