[AMD Official Use Only - Internal Distribution Only]
Hi Christian,
Since amdgpu_debugfs_wait_dump() would need 'audodump.dumping.done==0' to actually stop and wait for user mode app to dump.
Since usermode app might open a file , do nothing and close it. I believe a poll() function would be a better indicator that the usermode app actually wants to do a dump.
Also, a reset might happen between open() and poll(). The worst case would be wait_dump() would wait until timeout and usermode poll would always fail.
Jiange
-----Original Message-----
From: Christian König <ckoenig.leichtzumerken@xxxxxxxxx>
Sent: Wednesday, May 13, 2020 4:20 PM
To: Zhao, Jiange <Jiange.Zhao@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Pelloux-prayer, Pierre-eric <Pierre-eric.Pelloux-prayer@xxxxxxx>; Zhao, Jiange <Jiange.Zhao@xxxxxxx>; Koenig, Christian <Christian.Koenig@xxxxxxx>; Liu, Monk <Monk.Liu@xxxxxxx>
Subject: Re: [PATCH] drm/amdgpu: Add autodump debugfs node for gpu reset v4
Am 09.05.20 um 11:45 schrieb jianzh@xxxxxxx:
From: Jiange Zhao <Jiange.Zhao@xxxxxxx>
When GPU got timeout, it would notify an interested part of an
opportunity to dump info before actual GPU reset.
A usermode app would open 'autodump' node under debugfs system and
poll() for readable/writable. When a GPU reset is due, amdgpu would
notify usermode app through wait_queue_head and give it 10 minutes to
dump info.
After usermode app has done its work, this 'autodump' node is closed.
On node closure, amdgpu gets to know the dump is done through the
completion that is triggered in release().
There is no write or read callback because necessary info can be
obtained through dmesg and umr. Messages back and forth between
usermode app and amdgpu are unnecessary.
v2: (1) changed 'registered' to 'app_listening'
(2) add a mutex in open() to prevent race condition
v3 (chk): grab the reset lock to avoid race in autodump_open,
rename debugfs file to amdgpu_autodump,
provide autodump_read as well,
style and code cleanups
v4: add 'bool app_listening' to differentiate situations, so that
the node can be reopened; also, there is no need to wait for
completion when no app is waiting for a dump.
v5: change 'bool app_listening' to 'enum amdgpu_autodump_state'
add 'app_state_mutex' for race conditions:
(1)Only 1 user can open this file node
(2)wait_dump() can only take effect after poll() executed.
(3)eliminated the race condition between release() and
wait_dump()
v6: removed 'enum amdgpu_autodump_state' and 'app_state_mutex'
removed state checking in amdgpu_debugfs_wait_dump
Improve on top of version 3 so that the node can be reopened.
Signed-off-by: Jiange Zhao <Jiange.Zhao@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 2 +
drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 78 ++++++++++++++++++++-
drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h | 6 ++
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +
4 files changed, 87 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 2a806cb55b78..9e8eeddfe7ce 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -992,6 +992,8 @@ struct amdgpu_device {
char product_number[16];
char product_name[32];
char serial[16];
+
+ struct amdgpu_autodump autodump;
};
static inline struct amdgpu_device *amdgpu_ttm_adev(struct
ttm_bo_device *bdev) diff --git
a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
index 1a4894fa3693..261b67ece7fb 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
@@ -27,7 +27,7 @@
#include <linux/pci.h>
#include <linux/uaccess.h>
#include <linux/pm_runtime.h>
-
+#include <linux/poll.h>
#include <drm/drm_debugfs.h>
#include "amdgpu.h"
@@ -74,8 +74,82 @@ int amdgpu_debugfs_add_files(struct amdgpu_device *adev,
return 0;
}
+int amdgpu_debugfs_wait_dump(struct amdgpu_device *adev) { #if
+defined(CONFIG_DEBUG_FS)
+ unsigned long timeout = 600 * HZ;
+ int ret;
+
+ wake_up_interruptible(&adev->autodump.gpu_hang);
+
+ ret = wait_for_completion_interruptible_timeout(&adev->autodump.dumping, timeout);
+ complete_all(&adev->autodump.dumping);
+ if (ret == 0) {
+ pr_err("autodump: timeout, move on to gpu recovery\n");
+ return -ETIMEDOUT;
+ }
+#endif
+ return 0;
+}
+
#if defined(CONFIG_DEBUG_FS)
+static int amdgpu_debugfs_autodump_open(struct inode *inode, struct
+file *file) {
+ struct amdgpu_device *adev = inode->i_private;
+ int ret;
+
+ file->private_data = adev;
+
+ mutex_lock(&adev->lock_reset);
+ if (adev->autodump.dumping.done)
+ ret = 0;
+ else
+ ret = -EBUSY;
+ mutex_unlock(&adev->lock_reset);
+
+ return ret;
+}
+
+static int amdgpu_debugfs_autodump_release(struct inode *inode,
+struct file *file) {
+ struct amdgpu_device *adev = file->private_data;
+
+ complete_all(&adev->autodump.dumping);
+ return 0;
+}
+
+static unsigned int amdgpu_debugfs_autodump_poll(struct file *file,
+struct poll_table_struct *poll_table) {
+ struct amdgpu_device *adev = file->private_data;
+
+ reinit_completion(&adev->autodump.dumping);
Why do you have the reinit_completion here and not in open callback?
Apart from that looks good to me.
Regards,
Christian.
+ poll_wait(file, &adev->autodump.gpu_hang, poll_table);
+
+ if (adev->in_gpu_reset)
+ return POLLIN | POLLRDNORM | POLLWRNORM;
+
+ return 0;
+}
+
+static const struct file_operations autodump_debug_fops = {
+ .owner = THIS_MODULE,
+ .open = amdgpu_debugfs_autodump_open,
+ .poll = amdgpu_debugfs_autodump_poll,
+ .release = amdgpu_debugfs_autodump_release, };
+
+static void amdgpu_debugfs_autodump_init(struct amdgpu_device *adev)
+{
+ init_completion(&adev->autodump.dumping);
+ complete_all(&adev->autodump.dumping);
+ init_waitqueue_head(&adev->autodump.gpu_hang);
+
+ debugfs_create_file("amdgpu_autodump", 0600,
+ adev->ddev->primary->debugfs_root,
+ adev, &autodump_debug_fops);
+}
+
/**
* amdgpu_debugfs_process_reg_op - Handle MMIO register reads/writes
*
@@ -1434,6 +1508,8 @@ int amdgpu_debugfs_init(struct amdgpu_device
*adev)
amdgpu_ras_debugfs_create_all(adev);
+ amdgpu_debugfs_autodump_init(adev);
+
return amdgpu_debugfs_add_files(adev, amdgpu_debugfs_list,
ARRAY_SIZE(amdgpu_debugfs_list));
}
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
index de12d1101526..2803884d338d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
@@ -31,6 +31,11 @@ struct amdgpu_debugfs {
unsigned num_files;
};
+struct amdgpu_autodump {
+ struct completion dumping;
+ struct wait_queue_head gpu_hang;
+};
+
int amdgpu_debugfs_regs_init(struct amdgpu_device *adev);
int amdgpu_debugfs_init(struct amdgpu_device *adev);
void amdgpu_debugfs_fini(struct amdgpu_device *adev); @@ -40,3 +45,4
@@ int amdgpu_debugfs_add_files(struct amdgpu_device *adev,
int amdgpu_debugfs_fence_init(struct amdgpu_device *adev);
int amdgpu_debugfs_firmware_init(struct amdgpu_device *adev);
int amdgpu_debugfs_gem_init(struct amdgpu_device *adev);
+int amdgpu_debugfs_wait_dump(struct amdgpu_device *adev);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index cc41e8f5ad14..545beebcf43e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3927,6 +3927,8 @@ static int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev,
int i, r = 0;
bool need_full_reset = *need_full_reset_arg;
+ amdgpu_debugfs_wait_dump(adev);
+
/* block all schedulers and reset given job's ring */
for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
struct amdgpu_ring *ring = adev->rings[i];
