Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752557AbZLBLTe (ORCPT ); Wed, 2 Dec 2009 06:19:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751340AbZLBLTd (ORCPT ); Wed, 2 Dec 2009 06:19:33 -0500 Received: from fg-out-1718.google.com ([72.14.220.157]:54582 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751192AbZLBLTc (ORCPT ); Wed, 2 Dec 2009 06:19:32 -0500 Message-ID: <4B164D48.1040508@petalogix.com> Date: Wed, 02 Dec 2009 12:19:36 +0100 From: Michal Simek Reply-To: michal.simek@petalogix.com User-Agent: Thunderbird 2.0.0.18 (X11/20081120) MIME-Version: 1.0 To: Tejun Heo CC: Ingo Molnar , Christoph Lameter , Stephen Rothwell , linux-next@vger.kernel.org, LKML , Rusty Russell Subject: Re: problems in linux-next (Was: Re: linux-next: Tree for December 1) References: <20091201190301.0fb7abad.sfr@canb.auug.org.au> <4B14D6E2.2040704@petalogix.com> <20091201210343.f0a1d353.sfr@canb.auug.org.au> <4B152D22.9070001@kernel.org> <20091201160119.GA10826@elte.hu> <4B15A5A6.2090200@kernel.org> <4B161D7A.6040208@kernel.org> In-Reply-To: <4B161D7A.6040208@kernel.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7543 Lines: 214 Hi Tejun, Tejun Heo wrote: > Hello, > > It will look like the following. I have problem to apply your patch against Stephens next tree. Which tree do you use? Thanks, Michal [monstr@notebook linux-next]$ git reset --hard next-20091201 HEAD is now at 16aa569 Add linux-next specific files for 20091201 [monstr@notebook linux-next]$ git-am < problems\ in\ linux-next\ \(Was\:\ Re\:\ linux-next\:\ Tree\ for\ December\ 1\).eml previous dotest directory .dotest still exists but mbox given. [monstr@notebook linux-next]$ rm -rf .dotest/ [monstr@notebook linux-next]$ git-am < problems\ in\ linux-next\ \(Was\:\ Re\:\ linux-next\:\ Tree\ for\ December\ 1\).eml Applying problems in linux-next (Was: Re: linux-next: Tree for December 1) error: patch failed: include/linux/workqueue.h:29 error: include/linux/workqueue.h: patch does not apply error: patch failed: kernel/workqueue.c:46 error: kernel/workqueue.c: patch does not apply Patch failed at 0001. When you have resolved this problem run "git-am --resolved". If you would prefer to skip this patch, instead run "git-am --skip". [monstr@notebook linux-next]$ git-am < problems\ in\ linux-next\ \(Was\:\ Re\:\ linux-next\:\ Tree\ for\ December\ 1\).eml Applying problems in linux-next (Was: Re: linux-next: Tree for December 1) error: patch failed: include/linux/workqueue.h:29 error: include/linux/workqueue.h: patch does not apply error: patch failed: kernel/workqueue.c:46 error: kernel/workqueue.c: patch does not apply Patch failed at 0001. When you have resolved this problem run "git-am --resolved". If you would prefer to skip this patch, instead run "git-am --skip". > > Thanks. > > ========================================================================= > Subject: workqueue: update cwq alignement > > work->data field is used for two purposes. It points to cwq it's > queued on and the lower bits are used for flags. Currently, two bits > are reserved which is always safe as 4 byte alignment is guaranteed on > every architecture. However, future changes will need more flag bits. > > On SMP, the percpu allocator is capable of honoring larger alignment > (there are other users which depend on it) and larger alignment works > just fine. On UP, percpu allocator is a thin wrapper around > kzalloc/kfree() and don't honor alignment request. > > This patch introduces WORK_STRUCT_FLAG_BITS, aligns cwqs accordingly > and implements alloc/free_cwqs() which guarantees the alignment both > on SMP and UP. On SMP, simply wrapping percpu allocator is enouhg. > On UP, extra space is allocated so that cwq can be aligned and the > original pointer can be stored after it which is used in the free > path. > > While at it, as cwqs are now forced aligned, make sure the resulting > alignment is at least equal to or larger than that of long long. > > Signed-off-by: Tejun Heo > Cc: Christoph Lameter > Cc: Ingo Molnar > --- > include/linux/workqueue.h | 4 ++- > kernel/workqueue.c | 58 ++++++++++++++++++++++++++++++++++++++++++---- > 2 files changed, 56 insertions(+), 6 deletions(-) > > Index: work/include/linux/workqueue.h > =================================================================== > --- work.orig/include/linux/workqueue.h > +++ work/include/linux/workqueue.h > @@ -29,7 +29,9 @@ enum { > WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT, > WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT, > > - WORK_STRUCT_FLAG_MASK = 3UL, > + WORK_STRUCT_FLAG_BITS = 2, > + > + WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1, > WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK, > }; > > Index: work/kernel/workqueue.c > =================================================================== > --- work.orig/kernel/workqueue.c > +++ work/kernel/workqueue.c > @@ -46,7 +46,9 @@ > > /* > * The per-CPU workqueue (if single thread, we always use the first > - * possible cpu). > + * possible cpu). The lower WORK_STRUCT_FLAG_BITS of > + * work_struct->data are used for flags and thus cwqs need to be > + * aligned at two's power of the number of flag bits. > */ > struct cpu_workqueue_struct { > > @@ -58,7 +60,7 @@ struct cpu_workqueue_struct { > > struct workqueue_struct *wq; /* I: the owning workqueue */ > struct task_struct *thread; > -} ____cacheline_aligned; > +} __attribute__((aligned(1 << WORK_STRUCT_FLAG_BITS))); > > /* > * The externally visible workqueue abstraction is an array of > @@ -932,6 +934,44 @@ int current_is_keventd(void) > > } > > +static struct cpu_workqueue_struct *alloc_cwqs(void) > +{ > + const size_t size = sizeof(struct cpu_workqueue_struct); > + const size_t align = __alignof__(struct cpu_workqueue_struct); > + struct cpu_workqueue_struct *cwqs; > +#ifndef CONFIG_SMP > + void *ptr; > + > + /* > + * On UP, percpu allocator doesn't honor alignment parameter > + * and simply uses arch-dependent default. 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 = __alloc_percpu(size + align + sizeof(void *), 1); > + cwqs = PTR_ALIGN(ptr, align); > + *(void **)per_cpu_ptr(cwqs + 1, 0) = ptr; > +#else > + /* On SMP, percpu allocator can do it itself */ > + cwqs = __alloc_percpu(size, align); > +#endif > + /* just in case, make sure it's actually aligned */ > + BUG_ON(!IS_ALIGNED((unsigned long)cwqs, align)); > + return cwqs; > +} > + > +static void free_cwqs(struct cpu_workqueue_struct *cwqs) > +{ > +#ifndef CONFIG_SMP > + /* on UP, the pointer to free is stored right after the cwq */ > + if (cwqs) > + free_percpu(*(void **)per_cpu_ptr(cwqs + 1, 0)); > +#else > + free_percpu(cwqs); > +#endif > +} > + > static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) > { > struct workqueue_struct *wq = cwq->wq; > @@ -977,7 +1017,7 @@ struct workqueue_struct *__create_workqu > if (!wq) > goto err; > > - wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); > + wq->cpu_wq = alloc_cwqs(); > if (!wq->cpu_wq) > goto err; > > @@ -1023,7 +1063,7 @@ struct workqueue_struct *__create_workqu > return wq; > err: > if (wq) { > - free_percpu(wq->cpu_wq); > + free_cwqs(wq->cpu_wq); > kfree(wq); > } > return NULL; > @@ -1074,7 +1114,7 @@ void destroy_workqueue(struct workqueue_ > for_each_possible_cpu(cpu) > cleanup_workqueue_thread(get_cwq(cpu, wq)); > > - free_percpu(wq->cpu_wq); > + free_cwqs(wq->cpu_wq); > kfree(wq); > } > EXPORT_SYMBOL_GPL(destroy_workqueue); > @@ -1163,6 +1203,14 @@ EXPORT_SYMBOL_GPL(work_on_cpu); > > void __init init_workqueues(void) > { > + /* > + * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. > + * Make sure that the alignment isn't lower than that of > + * unsigned long long. > + */ > + BUILD_BUG_ON(__alignof__(struct cpu_workqueue_struct) < > + __alignof__(unsigned long long)); > + > singlethread_cpu = cpumask_first(cpu_possible_mask); > hotcpu_notifier(workqueue_cpu_callback, 0); > keventd_wq = create_workqueue("events"); -- Michal Simek, Ing. (M.Eng) PetaLogix - Linux Solutions for a Reconfigurable World w: www.petalogix.com p: +61-7-30090663,+42-0-721842854 f: +61-7-30090663 -- 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/