Hi,
On 17/02/16 23:18, yu.dai@xxxxxxxxx wrote:
From: Alex Dai <yu.dai@xxxxxxxxx>
GuC client object is always pinned during its life cycle. We cache
the vmap of client object, which includes guc_process_desc, doorbell
and work queue. By doing so, we can simplify the code where driver
communicate with GuC.
As a result, this patch removes the kmap_atomic in wq_check_space,
where usleep_range could be called while kmap_atomic is held. This
fixes issue below.
[ 34.098798] BUG: scheduling while atomic: gem_close_race/1941/0x00000002
[ 34.098822] Modules linked in: hid_generic usbhid i915 asix usbnet libphy mii i2c_algo_bit drm_kms_helper cfbfillrect syscopyarea cfbimgblt sysfillrect sysimgblt fb_sys_fops cfbcopyarea drm coretemp i2c_hid hid video pinctrl_sunrisepoint pinctrl_intel acpi_pad nls_iso8859_1 e1000e ptp psmouse pps_core ahci libahci
[ 34.098824] CPU: 0 PID: 1941 Comm: gem_close_race Tainted: G U 4.4.0-160121+ #123
[ 34.098824] Hardware name: Intel Corporation Skylake Client platform/Skylake AIO DDR3L RVP10, BIOS SKLSE2R1.R00.X100.B01.1509220551 09/22/2015
[ 34.098825] 0000000000013e40 ffff880166c27a78 ffffffff81280d02 ffff880172c13e40
[ 34.098826] ffff880166c27a88 ffffffff810c203a ffff880166c27ac8 ffffffff814ec808
[ 34.098827] ffff88016b7c6000 ffff880166c28000 00000000000f4240 0000000000000001
[ 34.098827] Call Trace:
[ 34.098831] [<ffffffff81280d02>] dump_stack+0x4b/0x79
[ 34.098833] [<ffffffff810c203a>] __schedule_bug+0x41/0x4f
[ 34.098834] [<ffffffff814ec808>] __schedule+0x5a8/0x690
[ 34.098835] [<ffffffff814ec927>] schedule+0x37/0x80
[ 34.098836] [<ffffffff814ef3fd>] schedule_hrtimeout_range_clock+0xad/0x130
[ 34.098837] [<ffffffff81090be0>] ? hrtimer_init+0x10/0x10
[ 34.098838] [<ffffffff814ef3f1>] ? schedule_hrtimeout_range_clock+0xa1/0x130
[ 34.098839] [<ffffffff814ef48e>] schedule_hrtimeout_range+0xe/0x10
[ 34.098840] [<ffffffff814eef9b>] usleep_range+0x3b/0x40
[ 34.098853] [<ffffffffa01ec109>] i915_guc_wq_check_space+0x119/0x210 [i915]
[ 34.098861] [<ffffffffa01da47c>] intel_logical_ring_alloc_request_extras+0x5c/0x70 [i915]
[ 34.098869] [<ffffffffa01cdbf1>] i915_gem_request_alloc+0x91/0x170 [i915]
[ 34.098875] [<ffffffffa01c1c07>] i915_gem_do_execbuffer.isra.25+0xbc7/0x12a0 [i915]
[ 34.098882] [<ffffffffa01cb785>] ? i915_gem_object_get_pages_gtt+0x225/0x3c0 [i915]
[ 34.098889] [<ffffffffa01d1fb6>] ? i915_gem_pwrite_ioctl+0xd6/0x9f0 [i915]
[ 34.098895] [<ffffffffa01c2e68>] i915_gem_execbuffer2+0xa8/0x250 [i915]
[ 34.098900] [<ffffffffa00f65d8>] drm_ioctl+0x258/0x4f0 [drm]
[ 34.098906] [<ffffffffa01c2dc0>] ? i915_gem_execbuffer+0x340/0x340 [i915]
[ 34.098908] [<ffffffff8111590d>] do_vfs_ioctl+0x2cd/0x4a0
[ 34.098909] [<ffffffff8111eac2>] ? __fget+0x72/0xb0
[ 34.098910] [<ffffffff81115b1c>] SyS_ioctl+0x3c/0x70
[ 34.098911] [<ffffffff814effd7>] entry_SYSCALL_64_fastpath+0x12/0x6a
[ 34.100208] ------------[ cut here ]------------
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93847
Cc: Dave Gordon <david.s.gordon@xxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Signed-off-by: Alex Dai <yu.dai@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_guc_submission.c | 53 +++++++++---------------------
drivers/gpu/drm/i915/intel_guc.h | 3 +-
2 files changed, 18 insertions(+), 38 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index d7543ef..3d6a1f7 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -195,11 +195,9 @@ static int guc_ring_doorbell(struct i915_guc_client *gc)
struct guc_process_desc *desc;
union guc_doorbell_qw db_cmp, db_exc, db_ret;
union guc_doorbell_qw *db;
- void *base;
int attempt = 2, ret = -EAGAIN;
- base = kmap_atomic(i915_gem_object_get_page(gc->client_obj, 0));
- desc = base + gc->proc_desc_offset;
+ desc = gc->client_base + gc->proc_desc_offset;
/* Update the tail so it is visible to GuC */
desc->tail = gc->wq_tail;
@@ -215,7 +213,7 @@ static int guc_ring_doorbell(struct i915_guc_client *gc)
db_exc.cookie = 1;
/* pointer of current doorbell cacheline */
- db = base + gc->doorbell_offset;
+ db = gc->client_base + gc->doorbell_offset;
while (attempt--) {
/* lets ring the doorbell */
@@ -244,10 +242,6 @@ static int guc_ring_doorbell(struct i915_guc_client *gc)
db_exc.cookie = 1;
}
- /* Finally, update the cached copy of the GuC's WQ head */
- gc->wq_head = desc->head;
-
- kunmap_atomic(base);
return ret;
}
@@ -341,10 +335,8 @@ static void guc_init_proc_desc(struct intel_guc *guc,
struct i915_guc_client *client)
{
struct guc_process_desc *desc;
- void *base;
- base = kmap_atomic(i915_gem_object_get_page(client->client_obj, 0));
- desc = base + client->proc_desc_offset;
+ desc = client->client_base + client->proc_desc_offset;
memset(desc, 0, sizeof(*desc));
@@ -361,8 +353,6 @@ static void guc_init_proc_desc(struct intel_guc *guc,
desc->wq_size_bytes = client->wq_size;
desc->wq_status = WQ_STATUS_ACTIVE;
desc->priority = client->priority;
-
- kunmap_atomic(base);
}
/*
@@ -474,25 +464,16 @@ static void guc_fini_ctx_desc(struct intel_guc *guc,
int i915_guc_wq_check_space(struct i915_guc_client *gc)
{
struct guc_process_desc *desc;
- void *base;
u32 size = sizeof(struct guc_wq_item);
int ret = -ETIMEDOUT, timeout_counter = 200;
if (!gc)
return 0;
- /* Quickly return if wq space is available since last time we cache the
- * head position. */
- if (CIRC_SPACE(gc->wq_tail, gc->wq_head, gc->wq_size) >= size)
- return 0;
-
- base = kmap_atomic(i915_gem_object_get_page(gc->client_obj, 0));
- desc = base + gc->proc_desc_offset;
+ desc = gc->client_base + gc->proc_desc_offset;
while (timeout_counter-- > 0) {
- gc->wq_head = desc->head;
-
- if (CIRC_SPACE(gc->wq_tail, gc->wq_head, gc->wq_size) >= size) {
+ if (CIRC_SPACE(gc->wq_tail, desc->head, gc->wq_size) >= size) {
ret = 0;
break;
}
@@ -501,24 +482,23 @@ int i915_guc_wq_check_space(struct i915_guc_client *gc)
usleep_range(1000, 2000);
};
- kunmap_atomic(base);
-
return ret;
}
static int guc_add_workqueue_item(struct i915_guc_client *gc,
struct drm_i915_gem_request *rq)
{
+ struct guc_process_desc *desc;
struct guc_wq_item *wqi;
- void *base;
- u32 tail, wq_len, wq_off, space;
+ u32 tail, wq_len, wqi_off, space;
- space = CIRC_SPACE(gc->wq_tail, gc->wq_head, gc->wq_size);
+ desc = gc->client_base + gc->proc_desc_offset;
+ space = CIRC_SPACE(gc->wq_tail, desc->head, gc->wq_size);
if (WARN_ON(space < sizeof(struct guc_wq_item)))
return -ENOSPC; /* shouldn't happen */
/* postincrement WQ tail for next time */
- wq_off = gc->wq_tail;
+ wqi_off = gc->wq_tail;
gc->wq_tail += sizeof(struct guc_wq_item);
gc->wq_tail &= gc->wq_size - 1;
@@ -530,13 +510,10 @@ static int guc_add_workqueue_item(struct i915_guc_client *gc,
* workqueue buffer dw by dw.
*/
WARN_ON(sizeof(struct guc_wq_item) != 16);
- WARN_ON(wq_off & 3);
+ WARN_ON(wqi_off & 3);
/* wq starts from the page after doorbell / process_desc */
- base = kmap_atomic(i915_gem_object_get_page(gc->client_obj,
- (wq_off + GUC_DB_SIZE) >> PAGE_SHIFT));
- wq_off &= PAGE_SIZE - 1;
- wqi = (struct guc_wq_item *)((char *)base + wq_off);
+ wqi = gc->client_base + gc->wq_offset + wqi_off;
/* len does not include the header */
wq_len = sizeof(struct guc_wq_item) / sizeof(u32) - 1;
@@ -553,8 +530,6 @@ static int guc_add_workqueue_item(struct i915_guc_client *gc,
wqi->ring_tail = tail << WQ_RING_TAIL_SHIFT;
wqi->fence_id = 0; /*XXX: what fence to be here */
- kunmap_atomic(base);
-
return 0;
}
@@ -675,6 +650,8 @@ static void guc_client_free(struct drm_device *dev,
* Be sure to drop any locks
*/
+ vunmap(client->client_base);
+
gem_release_guc_obj(client->client_obj);
if (client->ctx_index != GUC_INVALID_CTX_ID) {
@@ -727,6 +704,8 @@ static struct i915_guc_client *guc_client_alloc(struct drm_device *dev,
if (!obj)
goto err;
+ client->client_base = i915_gem_object_vmap(obj, 0, obj->pages->nents);
As per comments in the previous patch, obj->pages->nents need to be
obj->base.size >> PAGE_SHIFT.
And also error checking?
+
client->client_obj = obj;
client->wq_offset = GUC_DB_SIZE;
client->wq_size = GUC_WQ_SIZE;
diff --git a/drivers/gpu/drm/i915/intel_guc.h b/drivers/gpu/drm/i915/intel_guc.h
index 73002e9..9f08bd7 100644
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -34,6 +34,8 @@ struct i915_guc_client {
uint32_t priority;
uint32_t ctx_index;
+ void *client_base;
+
uint32_t proc_desc_offset;
uint32_t doorbell_offset;
uint32_t cookie;
@@ -43,7 +45,6 @@ struct i915_guc_client {
uint32_t wq_offset;
uint32_t wq_size;
uint32_t wq_tail;
- uint32_t wq_head;
/* GuC submission statistics & status */
uint64_t submissions[GUC_MAX_ENGINES_NUM];
Regards,
Tvrtko
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