[PATCH v2] drm/xe: Faster devcoredump
Zanoni, Paulo R
paulo.r.zanoni at intel.com
Fri Jul 26 22:01:17 UTC 2024
On Thu, 2024-07-25 at 22:21 -0700, Matthew Brost wrote:
> The current algorithm to read out devcoredump is O(N*N) where N is the
> size of coredump due to usage of the drm_coredump_printer in
> xe_devcoredump_read. Switch to a O(N) algorithm which prints the
> devcoredump into a readable format in snapshot work and update
> xe_devcoredump_read to memcpy from the readable format directly.
I just tested this:
root at martianriver:~# time cp /sys/class/drm/card0/device/devcoredump/data gpu-hang.data
real 0m0.313s
user 0m0.008s
sys 0m0.298s
root at martianriver:~# ls -lh gpu-hang.data
-rw------- 1 root root 221M Jul 26 14:47 gpu-hang.data
Going from an estimated 221 minutes to 0.3 seconds, I'd say it's an improvement.
>
> v2:
> - Fix double free on devcoredump removal (Testing)
> - Set read_data_size after snap work flush
> - Adjust remaining in iterator upon realloc (Testing)
> - Set read_data upon realloc (Testing)
>
> Reported-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2408
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> ---
> drivers/gpu/drm/xe/xe_devcoredump.c | 140 +++++++++++++++++-----
> drivers/gpu/drm/xe/xe_devcoredump.h | 13 ++
> drivers/gpu/drm/xe/xe_devcoredump_types.h | 4 +
> drivers/gpu/drm/xe/xe_vm.c | 9 +-
> drivers/gpu/drm/xe/xe_vm.h | 4 +-
> 5 files changed, 136 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
> index d8d8ca2c19d3..6af161250a9e 100644
> --- a/drivers/gpu/drm/xe/xe_devcoredump.c
> +++ b/drivers/gpu/drm/xe/xe_devcoredump.c
> @@ -66,22 +66,9 @@ static struct xe_guc *exec_queue_to_guc(struct xe_exec_queue *q)
> return &q->gt->uc.guc;
> }
>
> -static void xe_devcoredump_deferred_snap_work(struct work_struct *work)
> +static void __xe_devcoredump_read(char *buffer, size_t count,
> + struct xe_devcoredump *coredump)
> {
> - struct xe_devcoredump_snapshot *ss = container_of(work, typeof(*ss), work);
> -
> - /* keep going if fw fails as we still want to save the memory and SW data */
> - if (xe_force_wake_get(gt_to_fw(ss->gt), XE_FORCEWAKE_ALL))
> - xe_gt_info(ss->gt, "failed to get forcewake for coredump capture\n");
> - xe_vm_snapshot_capture_delayed(ss->vm);
> - xe_guc_exec_queue_snapshot_capture_delayed(ss->ge);
> - xe_force_wake_put(gt_to_fw(ss->gt), XE_FORCEWAKE_ALL);
> -}
> -
> -static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
> - size_t count, void *data, size_t datalen)
> -{
> - struct xe_devcoredump *coredump = data;
> struct xe_device *xe;
> struct xe_devcoredump_snapshot *ss;
> struct drm_printer p;
> @@ -89,18 +76,12 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
> struct timespec64 ts;
> int i;
>
> - if (!coredump)
> - return -ENODEV;
> -
> xe = coredump_to_xe(coredump);
> ss = &coredump->snapshot;
>
> - /* Ensure delayed work is captured before continuing */
> - flush_work(&ss->work);
> -
> iter.data = buffer;
> iter.offset = 0;
> - iter.start = offset;
> + iter.start = 0;
> iter.remain = count;
>
> p = drm_coredump_printer(&iter);
> @@ -129,15 +110,86 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
> xe_hw_engine_snapshot_print(coredump->snapshot.hwe[i],
> &p);
> drm_printf(&p, "\n**** VM state ****\n");
> - xe_vm_snapshot_print(coredump->snapshot.vm, &p);
> + xe_vm_snapshot_print(ss, coredump->snapshot.vm, &p);
>
> - return count - iter.remain;
> + ss->read_data_size = iter.offset;
> +}
> +
> +static void xe_devcoredump_snapshot_free(struct xe_devcoredump_snapshot *ss)
> +{
> + int i;
> +
> + xe_guc_ct_snapshot_free(ss->ct);
> + ss->ct = NULL;
> +
> + xe_guc_exec_queue_snapshot_free(ss->ge);
> + ss->ge = NULL;
> +
> + xe_sched_job_snapshot_free(ss->job);
> + ss->job = NULL;
> +
> + for (i = 0; i < XE_NUM_HW_ENGINES; i++)
> + if (ss->hwe[i]) {
> + xe_hw_engine_snapshot_free(ss->hwe[i]);
> + ss->hwe[i] = NULL;
> + }
> +
> + xe_vm_snapshot_free(ss->vm);
> + ss->vm = NULL;
> +}
> +
> +static void xe_devcoredump_deferred_snap_work(struct work_struct *work)
> +{
> + struct xe_devcoredump_snapshot *ss = container_of(work, typeof(*ss), work);
> + struct xe_devcoredump *coredump = container_of(ss, typeof(*coredump), snapshot);
> +
> + /* keep going if fw fails as we still want to save the memory and SW data */
> + if (xe_force_wake_get(gt_to_fw(ss->gt), XE_FORCEWAKE_ALL))
> + xe_gt_info(ss->gt, "failed to get forcewake for coredump capture\n");
> + xe_vm_snapshot_capture_delayed(ss->vm);
> + xe_guc_exec_queue_snapshot_capture_delayed(ss->ge);
> + xe_force_wake_put(gt_to_fw(ss->gt), XE_FORCEWAKE_ALL);
> +
> + ss->read_data = kvmalloc(SZ_16M, GFP_USER);
> + if (!ss->read_data)
> + return;
> +
> + ss->read_data_size = SZ_16M;
> + __xe_devcoredump_read(ss->read_data, SZ_16M, coredump);
> + xe_devcoredump_snapshot_free(ss);
> +}
> +
> +static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
> + size_t count, void *data, size_t datalen)
> +{
> + struct xe_devcoredump *coredump = data;
> + struct xe_devcoredump_snapshot *ss;
> + ssize_t byte_copied;
> +
> + if (!coredump)
> + return -ENODEV;
> +
> + ss = &coredump->snapshot;
> +
> + /* Ensure delayed work is captured before continuing */
> + flush_work(&ss->work);
> +
> + if (!ss->read_data)
> + return -ENODEV;
> +
> + if (offset >= ss->read_data_size)
> + return 0;
> +
> + byte_copied = count < ss->read_data_size - offset ? count :
> + ss->read_data_size - offset;
> + memcpy(buffer, ss->read_data + offset, byte_copied);
> +
> + return byte_copied;
> }
>
> static void xe_devcoredump_free(void *data)
> {
> struct xe_devcoredump *coredump = data;
> - int i;
>
> /* Our device is gone. Nothing to do... */
> if (!data || !coredump_to_xe(coredump))
> @@ -145,13 +197,8 @@ static void xe_devcoredump_free(void *data)
>
> cancel_work_sync(&coredump->snapshot.work);
>
> - xe_guc_ct_snapshot_free(coredump->snapshot.ct);
> - xe_guc_exec_queue_snapshot_free(coredump->snapshot.ge);
> - xe_sched_job_snapshot_free(coredump->snapshot.job);
> - for (i = 0; i < XE_NUM_HW_ENGINES; i++)
> - if (coredump->snapshot.hwe[i])
> - xe_hw_engine_snapshot_free(coredump->snapshot.hwe[i]);
> - xe_vm_snapshot_free(coredump->snapshot.vm);
> + xe_devcoredump_snapshot_free(&coredump->snapshot);
> + kvfree(coredump->snapshot.read_data);
>
> /* To prevent stale data on next snapshot, clear everything */
> memset(&coredump->snapshot, 0, sizeof(coredump->snapshot));
> @@ -260,4 +307,33 @@ int xe_devcoredump_init(struct xe_device *xe)
> {
> return devm_add_action_or_reset(xe->drm.dev, xe_driver_devcoredump_fini, &xe->drm);
> }
> +
> +int xe_devcoredump_check_iterator(struct xe_devcoredump_snapshot *ss,
> + struct drm_printer *p, size_t len)
> +{
> + struct drm_print_iterator *iterator = p->arg;
> + size_t new_size;
> + void *new_data;
> +
> + if (ss->read_data_size > iterator->offset + len + SZ_4K)
> + return 0;
> +
> + new_size = roundup_pow_of_two(iterator->offset + len + SZ_4K);
> +
> + new_data = kvmalloc(new_size, GFP_USER);
> + if (!new_data)
> + return -ENOMEM;
> +
> + memcpy(new_data, iterator->data, iterator->offset);
> +
> + kvfree(iterator->data);
> +
> + iterator->data = new_data;
> + iterator->remain += new_size - ss->read_data_size;
> + ss->read_data_size = new_size;
> + ss->read_data = new_data;
> +
> + return 0;
> +}
> +
> #endif
> diff --git a/drivers/gpu/drm/xe/xe_devcoredump.h b/drivers/gpu/drm/xe/xe_devcoredump.h
> index e2fa65ce0932..8bbef2244d5c 100644
> --- a/drivers/gpu/drm/xe/xe_devcoredump.h
> +++ b/drivers/gpu/drm/xe/xe_devcoredump.h
> @@ -6,12 +6,18 @@
> #ifndef _XE_DEVCOREDUMP_H_
> #define _XE_DEVCOREDUMP_H_
>
> +#include <linux/types.h>
> +
> +struct drm_printer;
> +struct xe_devcoredump_snapshot;
> struct xe_device;
> struct xe_sched_job;
>
> #ifdef CONFIG_DEV_COREDUMP
> void xe_devcoredump(struct xe_sched_job *job);
> int xe_devcoredump_init(struct xe_device *xe);
> +int xe_devcoredump_check_iterator(struct xe_devcoredump_snapshot *ss,
> + struct drm_printer *p, size_t len);
> #else
> static inline void xe_devcoredump(struct xe_sched_job *job)
> {
> @@ -21,6 +27,13 @@ static inline int xe_devcoredump_init(struct xe_device *xe)
> {
> return 0;
> }
> +
> +static inline int
> +xe_devcoredump_check_iterator(struct xe_devcoredump_snapshot *ss,
> + struct drm_printer *p, size_t len)
> +{
> + return 0;
> +}
> #endif
>
> #endif
> diff --git a/drivers/gpu/drm/xe/xe_devcoredump_types.h b/drivers/gpu/drm/xe/xe_devcoredump_types.h
> index 923cdf72a816..884802e46a98 100644
> --- a/drivers/gpu/drm/xe/xe_devcoredump_types.h
> +++ b/drivers/gpu/drm/xe/xe_devcoredump_types.h
> @@ -46,6 +46,10 @@ struct xe_devcoredump_snapshot {
> struct xe_sched_job_snapshot *job;
> /** @vm: Snapshot of VM state */
> struct xe_vm_snapshot *vm;
> + /** @read_data_size: size of read data */
> + size_t read_data_size;
> + /** @read_data: Read data */
> + void *read_data;
> };
>
> /**
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index 12d43c35978c..5cf45cb83676 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -25,6 +25,7 @@
> #include "xe_assert.h"
> #include "xe_bo.h"
> #include "xe_device.h"
> +#include "xe_devcoredump.h"
> #include "xe_drm_client.h"
> #include "xe_exec_queue.h"
> #include "xe_gt_pagefault.h"
> @@ -3366,9 +3367,11 @@ void xe_vm_snapshot_capture_delayed(struct xe_vm_snapshot *snap)
> }
> }
>
> -void xe_vm_snapshot_print(struct xe_vm_snapshot *snap, struct drm_printer *p)
> +void xe_vm_snapshot_print(struct xe_devcoredump_snapshot *ss,
> + struct xe_vm_snapshot *snap, struct drm_printer *p)
> {
> unsigned long i, j;
> + int err;
>
> if (IS_ERR_OR_NULL(snap)) {
> drm_printf(p, "[0].error: %li\n", PTR_ERR(snap));
> @@ -3384,6 +3387,10 @@ void xe_vm_snapshot_print(struct xe_vm_snapshot *snap, struct drm_printer *p)
> continue;
> }
>
> + err = xe_devcoredump_check_iterator(ss, p, snap->snap[i].len);
> + if (err < 0)
> + return;
> +
> drm_printf(p, "[%llx].data: ", snap->snap[i].ofs);
>
> for (j = 0; j < snap->snap[i].len; j += sizeof(u32)) {
> diff --git a/drivers/gpu/drm/xe/xe_vm.h b/drivers/gpu/drm/xe/xe_vm.h
> index c864dba35e1d..4537420b9c94 100644
> --- a/drivers/gpu/drm/xe/xe_vm.h
> +++ b/drivers/gpu/drm/xe/xe_vm.h
> @@ -19,6 +19,7 @@ struct drm_file;
> struct ttm_buffer_object;
> struct ttm_validate_buffer;
>
> +struct xe_devcoredump_snapshot;
> struct xe_exec_queue;
> struct xe_file;
> struct xe_sync_entry;
> @@ -279,5 +280,6 @@ static inline void vm_dbg(const struct drm_device *dev,
>
> struct xe_vm_snapshot *xe_vm_snapshot_capture(struct xe_vm *vm);
> void xe_vm_snapshot_capture_delayed(struct xe_vm_snapshot *snap);
> -void xe_vm_snapshot_print(struct xe_vm_snapshot *snap, struct drm_printer *p);
> +void xe_vm_snapshot_print(struct xe_devcoredump_snapshot *ss,
> + struct xe_vm_snapshot *snap, struct drm_printer *p);
> void xe_vm_snapshot_free(struct xe_vm_snapshot *snap);
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