[PATCH v2] drm/xe: Add config control for svm flush work

Wed May 7 20:14:31 UTC 2025

Hi Maintainers,
To avoid forgot the patch, could you please help me review and merge it when you are available?
Thanks in advance.

Shuicheng

On Fri, May 2, 2025 10:09 AM Brost, Matthew wrote:
> On Fri, May 02, 2025 at 05:00:52PM +0000, Shuicheng Lin wrote:
> > Without CONFIG_DRM_XE_GPUSVM set, GPU SVM is not initialized thus
> > below warning pops. Refine the flush work code to be controlled by the
> > config to avoid below warning:
> > "
> > [  453.132028] ------------[ cut here ]------------ [  453.132527]
> > WARNING: CPU: 9 PID: 4491 at kernel/workqueue.c:4205
> > __flush_work+0x379/0x3a0 [  453.133355] Modules linked in: xe
> drm_ttm_helper ttm gpu_sched drm_buddy drm_suballoc_helper
> drm_gpuvm drm_exec
> > [  453.134352] CPU: 9 UID: 0 PID: 4491 Comm: xe_exec_mix_mod Tainted:
> G     U  W           6.15.0-rc3+ #7 PREEMPT(full)
> > [  453.135405] Tainted: [U]=USER, [W]=WARN ...
> > [  453.136921] RIP: 0010:__flush_work+0x379/0x3a0 [  453.137417]
> Code:
> > 8b 45 00 48 8b 55 08 89 c7 48 c1 e8 04 83 e7 08 83 e0 0f 83 cf 02 89
> > c6 48 0f ba 6d 00 03 e9 d5 fe ff ff 0f 0b e9 db fd ff ff <0f> 0b 45 31
> > e4 e9 d1 fd ff ff 0f 0b e9 03 ff ff ff 0f 0b e9 d6 fe [  453.139250]
> > RSP: 0018:ffffc90000c67b18 EFLAGS: 00010246 [  453.139782] RAX:
> > 0000000000000000 RBX: ffff888108a24000 RCX: 0000000000002000 [
> > 453.140521] RDX: 0000000000000001 RSI: 0000000000000000 RDI:
> > ffff8881016d61c8 [  453.141253] RBP: ffff8881016d61c8 R08:
> > 0000000000000000 R09: 0000000000000000 [  453.141985] R10:
> > 0000000000000000 R11: 0000000008a24000 R12: 0000000000000001 [
> > 453.142709] R13: 0000000000000002 R14: 0000000000000000 R15:
> > ffff888107db8c00 [  453.143450] FS:  00007f44853d4c80(0000)
> > GS:ffff8882f469b000(0000) knlGS:0000000000000000 [  453.144276] CS:
> > 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [  453.144853] CR2:
> 00007f4487629228 CR3: 00000001016aa000 CR4: 00000000000406f0
> [  453.145594] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> 0000000000000000 [  453.146320] DR3: 0000000000000000 DR6:
> 00000000fffe0ff0 DR7: 0000000000000400 [  453.147061] Call Trace:
> > [  453.147336]  <TASK>
> > [  453.147579]  ? tick_nohz_tick_stopped+0xd/0x30 [  453.148067]  ?
> > xas_load+0x9/0xb0 [  453.148435]  ? xa_load+0x6f/0xb0 [  453.148781]
> > __xe_vm_bind_ioctl+0xbd5/0x1500 [xe] [  453.149338]  ?
> > dev_printk_emit+0x48/0x70 [  453.149762]  ? _dev_printk+0x57/0x80 [
> > 453.150148]  ? drm_ioctl+0x17c/0x440 [  453.150544]  ?
> > __drm_dev_vprintk+0x36/0x90 [  453.150983]  ?
> > __pfx_xe_vm_bind_ioctl+0x10/0x10 [xe] [  453.151575]  ?
> > drm_ioctl_kernel+0x9f/0xf0 [  453.151998]  ?
> > __pfx_xe_vm_bind_ioctl+0x10/0x10 [xe] [  453.152560]
> > drm_ioctl_kernel+0x9f/0xf0 [  453.152968]  drm_ioctl+0x20f/0x440 [
> > 453.153332]  ? __pfx_xe_vm_bind_ioctl+0x10/0x10 [xe] [  453.153893]  ?
> > ioctl_has_perm.constprop.0.isra.0+0xae/0x100
> > [  453.154489]  ? memory_bm_test_bit+0x5/0x60 [  453.154935]
> > xe_drm_ioctl+0x47/0x70 [xe] [  453.155419]  __x64_sys_ioctl+0x8d/0xc0
> > [  453.155824]  do_syscall_64+0x47/0x110 [  453.156228]
> > entry_SYSCALL_64_after_hwframe+0x76/0x7e
> > "
> >
> > v2 (Matt):
> >     refine commit message to have more details
> >     add Fixes tag
> >     move the code to xe_svm.h which already have the config
> >     remove a blank line per codestyle suggestion
> >
> > Fixes: 63f6e480d115 ("drm/xe: Add SVM garbage collector")
> > Cc: Matthew Brost <matthew.brost at intel.com>
> 
> Reviewed-by: Matthew Brost <matthew.brost at intel.com>
> 
> > Signed-off-by: Shuicheng Lin <shuicheng.lin at intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_svm.c | 13 ++++++++++++-
> > drivers/gpu/drm/xe/xe_svm.h |  6 ++++++  drivers/gpu/drm/xe/xe_vm.c  |
> > 3 +--
> >  3 files changed, 19 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
> > index 890f6b2f40e9..d25f02c8d7fc 100644
> > --- a/drivers/gpu/drm/xe/xe_svm.c
> > +++ b/drivers/gpu/drm/xe/xe_svm.c
> > @@ -726,7 +726,6 @@ static int xe_svm_alloc_vram(struct xe_vm *vm,
> > struct xe_tile *tile,  }  #endif
> >
> > -
> >  /**
> >   * xe_svm_handle_pagefault() - SVM handle page fault
> >   * @vm: The VM.
> > @@ -966,3 +965,15 @@ int xe_devm_add(struct xe_tile *tile, struct
> xe_vram_region *vr)
> >  	return 0;
> >  }
> >  #endif
> > +
> > +/**
> > + * xe_svm_flush() - SVM flush
> > + * @vm: The VM.
> > + *
> > + * Flush all SVM actions.
> > + */
> > +void xe_svm_flush(struct xe_vm *vm)
> > +{
> > +	if (xe_vm_in_fault_mode(vm))
> > +		flush_work(&vm->svm.garbage_collector.work);
> > +}
> > diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h
> > index 3d441eb1f7ea..2881af1e60b2 100644
> > --- a/drivers/gpu/drm/xe/xe_svm.h
> > +++ b/drivers/gpu/drm/xe/xe_svm.h
> > @@ -96,6 +96,8 @@ static inline bool
> xe_svm_range_has_dma_mapping(struct xe_svm_range *range)
> >  #define xe_svm_notifier_unlock(vm__)	\
> >  	drm_gpusvm_notifier_unlock(&(vm__)->svm.gpusvm)
> >
> > +void xe_svm_flush(struct xe_vm *vm);
> > +
> >  #else
> >  #include <linux/interval_tree.h>
> >
> > @@ -180,5 +182,9 @@ static inline void xe_svm_notifier_lock(struct
> > xe_vm *vm)  static inline void xe_svm_notifier_unlock(struct xe_vm
> > *vm)  {  }
> > +
> > +static inline void xe_svm_flush(struct xe_vm *vm) { }
> >  #endif
> >  #endif
> > diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> > index 2a9d58a4471c..91a0570abb16 100644
> > --- a/drivers/gpu/drm/xe/xe_vm.c
> > +++ b/drivers/gpu/drm/xe/xe_vm.c
> > @@ -3419,8 +3419,7 @@ int xe_vm_bind_ioctl(struct drm_device *dev,
> void *data, struct drm_file *file)
> >  	}
> >
> >  	/* Ensure all UNMAPs visible */
> > -	if (xe_vm_in_fault_mode(vm))
> > -		flush_work(&vm->svm.garbage_collector.work);
> > +	xe_svm_flush(vm);
> >
> >  	err = down_write_killable(&vm->lock);
> >  	if (err)
> > --
> > 2.25.1
> >