[PATCH v6 1/3] drm/i915/gvt: Use gtt_lock to protect gtt list
Colin Xu
Colin.Xu at intel.com
Fri Apr 20 08:01:46 UTC 2018
On 04/19/2018 03:40 PM, Du, Changbin wrote:
> On Fri, Apr 20, 2018 at 03:26:25PM +0800, colin.xu at intel.com wrote:
>> From: Pei Zhang <pei.zhang at intel.com>
>>
>> The patch set splits out 3 small locks from the original big gvt lock:
>> - gtt_lock is used to protect the gvt global gtt oos lists.
>> - vgpu_lock protects per-vGPU data and logic, especially the vGPU
>> trap emulation path.
>> - sched_lock protects gvt scheudler structure, context schedule logic
>> and vGPU's schedule data.
>>
>> GVT gtt contains 2 oos list, and one global mm list. Use a special
>> gvt->gtt_lock to protect those 3 lists.
>>
>> v6:
>> - Rebase to latest gvt-staging.
>> v5:
>> - Rebase to latest gvt-staging.
>> - gtt access is already protected by vgpu_lock, so gtt_lock is
>> unnecessary currently. Will keep for init/clean for further usage.
> Maybe we should delay this fully overlayed gtt_lock to when really needed.
> Who knows what the code will be changed to in future.
OK I'll remake the patch set to keep only vgpu_lock and sched_lock.
gtt_lock can be added when it's necessary.
> OK
>> v4:
>> - Rebase to latest gvt-staging.
>> - Add missing protection when access list in clean_spt_oos().
>> - Fix locked recursive call of detach_oos_page when cleanup. (zhenyu)
>> v3: Update to latest code base.
>> v2: use gtt_lock to cover correct scope in ppgtt_allocate_oos_page().
>>
>> Performance comparison on Kabylake platform.
>> - Configuration:
>> Host: Ubuntu 16.04.
>> Guest 1 & 2: Ubuntu 16.04.
>>
>> glmark2 score comparison:
>> - Configuration:
>> Host: glxgears.
>> Guests: glmark2.
>> +--------------------------------+-----------------+
>> | Setup | glmark2 score |
>> +--------------------------------+-----------------+
>> | unified lock, iommu=on | 58~62 (avg. 60) |
>> +--------------------------------+-----------------+
>> | unified lock, iommu=igfx_off | 57~61 (avg. 59) |
>> +--------------------------------+-----------------+
>> | per-logic lock, iommu=on | 60~68 (avg. 64) |
>> +--------------------------------+-----------------+
>> | per-logic lock, iommu=igfx_off | 61~67 (avg. 64) |
>> +--------------------------------+-----------------+
>>
>> lock_stat comparison:
>> - Configuration:
>> Stop lock stat immediately after boot up.
>> Boot 2 VM Guests.
>> Run glmark2 in guests.
>> Start perf lock_stat for 20 seconds and stop again.
>> - Legend: c - contentions; w - waittime-avg
>> +------------+-----------------+-----------+---------------+------------+
>> | | gvt_lock |sched_lock | vgpu_lock | gtt_lock |
>> + lock type; +-----------------+-----------+---------------+------------+
>> | iommu set | c | w | c | w | c | w | c | w |
>> +------------+-------+---------+----+------+------+--------+-----+------+
>> | unified; | 20697 | 839 |N/A | N/A | N/A | N/A | N/A | N/A |
>> | on | | | | | | | | |
>> +------------+-------+---------+----+------+------+--------+-----+------+
>> | unified; | 21838 | 658.15 |N/A | N/A | N/A | N/A | N/A | N/A |
>> | igfx_off | | | | | | | | |
>> +------------+-------+---------+----+------+------+--------+-----+------+
>> | per-logic; | 1553 | 1599.96 |9458|429.97| 5846 | 274.33 | 0 | 0.00 |
>> | on | | | | | | | | |
>> +------------+-------+---------+----+------+------+--------+-----+------+
>> | per-logic; | 1911 | 1678.32 |8335|445.16| 5451 | 244.80 | 0 | 0.00 |
>> | igfx_off | | | | | | | | |
>> +------------+-------+---------+----+------+------+--------+-----+------+
>>
>> Signed-off-by: Pei Zhang <pei.zhang at intel.com>
>> Signed-off-by: Colin Xu <colin.xu at intel.com>
>> ---
>> drivers/gpu/drm/i915/gvt/gtt.c | 7 +++++++
>> drivers/gpu/drm/i915/gvt/gvt.c | 1 +
>> drivers/gpu/drm/i915/gvt/gvt.h | 2 ++
>> 3 files changed, 10 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
>> index 78e55aafc8bc..9ad3b8105e73 100644
>> --- a/drivers/gpu/drm/i915/gvt/gtt.c
>> +++ b/drivers/gpu/drm/i915/gvt/gtt.c
>> @@ -2109,6 +2109,8 @@ static void clean_spt_oos(struct intel_gvt *gvt)
>> struct list_head *pos, *n;
>> struct intel_vgpu_oos_page *oos_page;
>>
>> + mutex_lock(&gvt->gtt_lock);
>> +
>> WARN(!list_empty(>t->oos_page_use_list_head),
>> "someone is still using oos page\n");
>>
>> @@ -2117,6 +2119,7 @@ static void clean_spt_oos(struct intel_gvt *gvt)
>> list_del(&oos_page->list);
>> kfree(oos_page);
>> }
>> + mutex_unlock(&gvt->gtt_lock);
>> }
>>
>> static int setup_spt_oos(struct intel_gvt *gvt)
>> @@ -2126,6 +2129,8 @@ static int setup_spt_oos(struct intel_gvt *gvt)
>> int i;
>> int ret;
>>
>> + mutex_lock(&gvt->gtt_lock);
>> +
>> INIT_LIST_HEAD(>t->oos_page_free_list_head);
>> INIT_LIST_HEAD(>t->oos_page_use_list_head);
>>
>> @@ -2142,6 +2147,8 @@ static int setup_spt_oos(struct intel_gvt *gvt)
>> list_add_tail(&oos_page->list, >t->oos_page_free_list_head);
>> }
>>
>> + mutex_unlock(&gvt->gtt_lock);
>> +
>> gvt_dbg_mm("%d oos pages preallocated\n", i);
>>
>> return 0;
>> diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
>> index 61bd14fcb649..91c37f115780 100644
>> --- a/drivers/gpu/drm/i915/gvt/gvt.c
>> +++ b/drivers/gpu/drm/i915/gvt/gvt.c
>> @@ -379,6 +379,7 @@ int intel_gvt_init_device(struct drm_i915_private *dev_priv)
>> idr_init(&gvt->vgpu_idr);
>> spin_lock_init(&gvt->scheduler.mmio_context_lock);
>> mutex_init(&gvt->lock);
>> + mutex_init(&gvt->gtt_lock);
>> gvt->dev_priv = dev_priv;
>>
>> init_device_info(gvt);
>> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
>> index 6ec888822a0f..8860343e850f 100644
>> --- a/drivers/gpu/drm/i915/gvt/gvt.h
>> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
>> @@ -296,6 +296,8 @@ struct intel_vgpu_type {
>>
>> struct intel_gvt {
>> struct mutex lock;
>> + struct mutex gtt_lock;
>> +
>> struct drm_i915_private *dev_priv;
>> struct idr vgpu_idr; /* vGPU IDR pool */
>>
>> --
>> 2.17.0
>>
>> _______________________________________________
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>> intel-gvt-dev at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev
--
Best Regards,
Colin Xu
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