<html> <head> <meta content="text/html; charset=utf-8" http-equiv="Content-Type"> </head> <body text="#000000" bgcolor="#FFFFFF"> <div class="moz-cite-prefix">On 2016年06月28日 18:03, Christian König wrote: </div> <blockquote cite="mid:57724B64.9060107@vodafone.de" type="cite"> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <div class="moz-cite-prefix">Am 28.06.2016 um 11:33 schrieb zhoucm1: </div> <blockquote cite="mid:5772444E.20309@amd.com" type="cite"> On 2016年06月28日 17:36, Christian König wrote: <blockquote type="cite">Am 28.06.2016 um 09:27 schrieb Huang Rui: <blockquote type="cite">On Tue, Jun 28, 2016 at 03:04:18PM +0800, Chunming Zhou wrote: <blockquote type="cite">ring_mirror_list is only used kthread context, no need to spinlock. otherwise deadlock happens when kthread_park. </blockquote> Yes, in process context, we prefer to use mutex, because it avoids to grab the CPU all the time. Reviewed-by: Huang Rui <a moz-do-not-send="true" class="moz-txt-link-rfc2396E" href="mailto:ray.huang@amd.com"><ray.huang@amd.com></a> </blockquote> NAK, the patch won't apply because I've changed the irq save spin lock to a normal one quite a while ago. But, I'm not sure if Alex picked up that patch yet. You shouldn't use a mutex here when you don't have a reason to do so. Spin locks have less overhead and we won't expect any contention here. Additional to that how should this cause a deadlock with kthread_park? </blockquote> you can apply another patch to drop hw ring, and then run glxgears, and hang the gfx with the attached, then you will find that deadlock info. </blockquote> Please provide the deadlock info. Since the spin lock only protects the linked list we should be able to easily avoid any lock inversion which could lead to a deadlock. </blockquote> With the latest code, you could easily reproduce it with above steps, after mutex, these deadlock info disappears: Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.282892] NMI watchdog: BUG: soft lockup - CPU#7 stuck for 22s! [kworker/7:0:58] Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283106] Modules linked in: amdgpu(OE) ttm(OE) drm_kms_helper(OE) drm(E) i2c_algo_bit(E) fb_sys_fops(E) syscopyarea(E) sysfillrect(E) sysimgblt(E) nfsv3(E) bnep(E) rfcomm(E) bluetooth(E) rpcsec_gss_krb5(E) nfsv4(E) nfsd(E) auth_rpcgss(E) nfs_acl(E) nfs(E) lockd(E) grace(E) sunrpc(E) fscache(E) binfmt_misc(E) snd_hda_codec_realtek(E) snd_hda_codec_hdmi(E) snd_hda_codec_generic(E) snd_hda_intel(E) snd_hda_codec(E) snd_hda_core(E) snd_hwdep(E) coretemp(E) snd_pcm(E) snd_seq_midi(E) snd_seq_midi_event(E) snd_rawmidi(E) snd_seq(E) joydev(E) kvm_intel(E) snd_seq_device(E) snd_timer(E) kvm(E) snd(E) soundcore(E) irqbypass(E) gpio_ich(E) mxm_wmi(E) serio_raw(E) shpchp(E) wmi(E) i7core_edac(E) edac_core(E) lpc_ich(E) parport_pc(E) mac_hid(E) ppdev(E) lp(E) parport(E) hid_generic(E) usbhid(E) hid(E) firewire_ohci(E) 8139too(E) pata_acpi(E) firewire_core(E) 8139cp(E) crc_itu_t(E) r8169(E) mii(E) pata_jmicron(E) ahci(E) libahci(E) Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283134] CPU: 7 PID: 58 Comm: kworker/7:0 Tainted: G IOE 4.5.0-custom #7 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283136] Hardware name: Gigabyte Technology Co., Ltd. X58A-UD3R/X58A-UD3R, BIOS FE 12/23/2010 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283182] Workqueue: events amd_sched_job_finish [amdgpu] Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283183] task: ffff8801a8490000 ti: ffff8801a848c000 task.ti: ffff8801a848c000 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283184] RIP: 0010:[<ffffffff810c1131>] [<ffffffff810c1131>] native_queued_spin_lock_slowpath+0x171/0x190 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283189] RSP: 0018:ffff8801a848fdc8 EFLAGS: 00000202 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283190] RAX: 0000000000000101 RBX: ffff8800c5ba1030 RCX: 0000000000000001 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283191] RDX: 0000000000000101 RSI: 0000000000000001 RDI: ffff8800c42a4518 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283192] RBP: ffff8801a848fdc8 R08: 0000000000000101 R09: ffff8801a93d6300 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283193] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8800c42a4468 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283194] R13: ffff8800c42a4518 R14: ffff8800c5ba1000 R15: ffff8800c5ba1030 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283195] FS: 0000000000000000(0000) GS:ffff8801a93c0000(0000) knlGS:0000000000000000 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283196] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283197] CR2: 00007efc3bc21e50 CR3: 0000000001c0c000 CR4: 00000000000006e0 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283198] Stack: Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283199] ffff8801a848fdd8 ffffffff81173ef2 ffff8801a848fde8 ffffffff817a19c0 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283200] ffff8801a848fe18 ffffffffa06937fb ffff8801a75deb40 ffff8801a93d6300 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283202] ffff8801a93dae00 00000000000001c0 ffff8801a848fe60 ffffffff81090bb0 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283203] Call Trace: Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283206] [<ffffffff81173ef2>] queued_spin_lock_slowpath+0xb/0xf Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283209] [<ffffffff817a19c0>] _raw_spin_lock+0x20/0x30 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283234] [<ffffffffa06937fb>] amd_sched_job_finish+0x2b/0xc0 [amdgpu] Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283237] [<ffffffff81090bb0>] process_one_work+0x150/0x3f0 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283239] [<ffffffff8109136b>] worker_thread+0x12b/0x4b0 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283241] [<ffffffff81091240>] ? rescuer_thread+0x340/0x340 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283242] [<ffffffff81096b22>] kthread+0xd2/0xf0 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283244] [<ffffffff81096a50>] ? kthread_park+0x50/0x50 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283246] [<ffffffff817a210f>] ret_from_fork+0x3f/0x70 Jun 28 14:34:25 zhoucm1-System-Product-Name kernel: [ 96.283247] [<ffffffff81096a50>] ? kthread_park+0x50/0x50 Regards, David Zhou <blockquote cite="mid:57724B64.9060107@vodafone.de" type="cite"> BTW: The debug patch you attached is not such a good idea either, cause you modify the gfx ring from outside the worker thread. Regards, Christian. <blockquote cite="mid:5772444E.20309@amd.com" type="cite"> Regards, David Zhou <blockquote type="cite"> Regards, Christian. <blockquote type="cite"> <blockquote type="cite">Change-Id: I906022297015faf14a0ddb5f62a728af3e5f9448 Signed-off-by: Chunming Zhou <a moz-do-not-send="true" class="moz-txt-link-rfc2396E" href="mailto:David1.Zhou@amd.com"><David1.Zhou@amd.com></a> --- drivers/gpu/drm/amd/scheduler/gpu_scheduler.c | 12 +++++------- drivers/gpu/drm/amd/scheduler/gpu_scheduler.h | 2 +- 2 files changed, 6 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c index b53cf58..3373d97 100644 --- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c +++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c @@ -331,10 +331,9 @@ static void amd_sched_job_finish(struct work_struct *work) struct amd_sched_job *s_job = container_of(work, struct amd_sched_job, finish_work); struct amd_gpu_scheduler *sched = s_job->sched; - unsigned long flags; /* remove job from ring_mirror_list */ - spin_lock_irqsave(&sched->job_list_lock, flags); + mutex_lock(&sched->job_list_lock); list_del_init(&s_job->node); if (sched->timeout != MAX_SCHEDULE_TIMEOUT) { struct amd_sched_job *next; @@ -348,7 +347,7 @@ static void amd_sched_job_finish(struct work_struct *work) if (next) schedule_delayed_work(&next->work_tdr, sched->timeout); } - spin_unlock_irqrestore(&sched->job_list_lock, flags); + mutex_unlock(&sched->job_list_lock); sched->ops->free_job(s_job); } @@ -362,15 +361,14 @@ static void amd_sched_job_finish_cb(struct fence *f, struct fence_cb *cb) static void amd_sched_job_begin(struct amd_sched_job *s_job) { struct amd_gpu_scheduler *sched = s_job->sched; - unsigned long flags; - spin_lock_irqsave(&sched->job_list_lock, flags); + mutex_lock(&sched->job_list_lock); list_add_tail(&s_job->node, &sched->ring_mirror_list); if (sched->timeout != MAX_SCHEDULE_TIMEOUT && list_first_entry_or_null(&sched->ring_mirror_list, struct amd_sched_job, node) == s_job) schedule_delayed_work(&s_job->work_tdr, sched->timeout); - spin_unlock_irqrestore(&sched->job_list_lock, flags); + mutex_unlock(&sched->job_list_lock); } static void amd_sched_job_timedout(struct work_struct *work) @@ -564,7 +562,7 @@ int amd_sched_init(struct amd_gpu_scheduler *sched, init_waitqueue_head(&sched->wake_up_worker); init_waitqueue_head(&sched->job_scheduled); INIT_LIST_HEAD(&sched->ring_mirror_list); - spin_lock_init(&sched->job_list_lock); + mutex_init(&sched->job_list_lock); atomic_set(&sched->hw_rq_count, 0); if (atomic_inc_return(&sched_fence_slab_ref) == 1) { sched_fence_slab = kmem_cache_create( diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h index 221a515..5675906 100644 --- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h +++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h @@ -132,7 +132,7 @@ struct amd_gpu_scheduler { atomic_t hw_rq_count; struct task_struct *thread; struct list_head ring_mirror_list; - spinlock_t job_list_lock; + struct mutex job_list_lock; }; int amd_sched_init(struct amd_gpu_scheduler *sched, -- 1.9.1 _______________________________________________ amd-gfx mailing list <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a> <a moz-do-not-send="true" class="moz-txt-link-freetext" href="https://lists.freedesktop.org/mailman/listinfo/amd-gfx">https://lists.freedesktop.org/mailman/listinfo/amd-gfx</a> </blockquote> _______________________________________________ amd-gfx mailing list <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a> <a moz-do-not-send="true" class="moz-txt-link-freetext" href="https://lists.freedesktop.org/mailman/listinfo/amd-gfx">https://lists.freedesktop.org/mailman/listinfo/amd-gfx</a> </blockquote> _______________________________________________ amd-gfx mailing list <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a> <a moz-do-not-send="true" class="moz-txt-link-freetext" href="https://lists.freedesktop.org/mailman/listinfo/amd-gfx">https://lists.freedesktop.org/mailman/listinfo/amd-gfx</a> </blockquote> <fieldset class="mimeAttachmentHeader"></fieldset> <pre wrap="">_______________________________________________ amd-gfx mailing list <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a> <a moz-do-not-send="true" class="moz-txt-link-freetext" href="https://lists.freedesktop.org/mailman/listinfo/amd-gfx">https://lists.freedesktop.org/mailman/listinfo/amd-gfx</a> </pre> </blockquote> </blockquote> </body> </html>