From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx156.postini.com [74.125.245.156]) by kanga.kvack.org (Postfix) with SMTP id AF18C6B0044 for ; Tue, 20 Mar 2012 11:46:24 -0400 (EDT) Received: by yhr47 with SMTP id 47so239050yhr.14 for ; Tue, 20 Mar 2012 08:46:23 -0700 (PDT) Date: Tue, 20 Mar 2012 08:46:19 -0700 From: Tejun Heo Subject: Re: [RFC PATCH 6/6] workqueue: use kmalloc_align() instead of hacking Message-ID: <20120320154619.GA5684@google.com> References: <1332238884-6237-1-git-send-email-laijs@cn.fujitsu.com> <1332238884-6237-7-git-send-email-laijs@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1332238884-6237-7-git-send-email-laijs@cn.fujitsu.com> Sender: owner-linux-mm@kvack.org List-ID: To: Lai Jiangshan Cc: Christoph Lameter , Pekka Enberg , Matt Mackall , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Tue, Mar 20, 2012 at 06:21:24PM +0800, Lai Jiangshan wrote: > kmalloc_align() makes the code simpler. > > Signed-off-by: Lai Jiangshan > --- > kernel/workqueue.c | 23 +++++------------------ > 1 files changed, 5 insertions(+), 18 deletions(-) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 5abf42f..beec5fd 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -2897,20 +2897,9 @@ static int alloc_cwqs(struct workqueue_struct *wq) > > if (!(wq->flags & WQ_UNBOUND)) > wq->cpu_wq.pcpu = __alloc_percpu(size, align); > - else { > - void *ptr; > - > - /* > - * Allocate enough room to align cwq and put an extra > - * pointer at the end pointing back to the originally > - * allocated pointer which will be used for free. > - */ > - ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL); > - if (ptr) { > - wq->cpu_wq.single = PTR_ALIGN(ptr, align); > - *(void **)(wq->cpu_wq.single + 1) = ptr; > - } > - } > + else > + wq->cpu_wq.single = kmalloc_align(size, > + GFP_KERNEL | __GFP_ZERO, align); > > /* just in case, make sure it's actually aligned */ > BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align)); > @@ -2921,10 +2910,8 @@ static void free_cwqs(struct workqueue_struct *wq) > { > if (!(wq->flags & WQ_UNBOUND)) > free_percpu(wq->cpu_wq.pcpu); > - else if (wq->cpu_wq.single) { > - /* the pointer to free is stored right after the cwq */ > - kfree(*(void **)(wq->cpu_wq.single + 1)); > - } > + else if (wq->cpu_wq.single) > + kfree(wq->cpu_wq.single); Yes, this is hacky but I don't think building the whole kmalloc_align() for only this is a good idea. If the open coded hack bothers you just write a simplistic wrapper somewhere. We can make that better integrated / more efficient when there are multiple users of the interface, which I kinda doubt would happen. The reason why cwq requiring larger alignment is more historic than anything else after all. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org