[PATCH v5 1/3] drm/i915/gvt: Use gtt_lock to protect gtt list
colin.xu at intel.com
colin.xu at intel.com
Thu Apr 5 08:27:37 UTC 2018
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.
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.
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 efacd8abbedc..01fe294eab74 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -295,6 +295,8 @@ 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 */
--
2.16.3
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