From mboxrd@z Thu Jan 1 00:00:00 1970 From: "xinhui.pan" Subject: [PATCH] md/dm-ioctl.c: optimize memory allocation in copy_params Date: Fri, 04 Jul 2014 18:22:32 +0800 Message-ID: <53B68068.2060102@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, agk@redhat.com, snitzer@redhat.com, dm-devel@redhat.com Cc: yanmin_zhang@linux.intel.com, "Liu, ShuoX" List-Id: dm-devel.ids KMALLOC_MAX_SIZE is too big, it easily cause memory fragmented and low memory when param_kernel->data_size is also big. That's not nice. So use vmalloc instead of kmalloc when size is larger than (PAGE_SIZE << 2). There are other drivers using kmalloc to gain a big size memory. And that cause our devices to hit hang and many worse issues. We don't benefit much when using kmalloc in such scenario. Signed-off-by: xinhui.pan Signed-off-by: yanmin.zhang --- drivers/md/dm-ioctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 5152142..31c3af9 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1709,7 +1709,7 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern * Use kmalloc() rather than vmalloc() when we can. */ dmi = NULL; - if (param_kernel->data_size <= KMALLOC_MAX_SIZE) { + if (param_kernel->data_size <= (PAGE_SIZE << 2)) { dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); if (dmi) *param_flags |= DM_PARAMS_KMALLOC; -- 1.7.9.5