[PATCH v4 3/3] drm/xe: Faster devcoredump
Matthew Brost
matthew.brost at intel.com
Thu Aug 1 00:00:41 UTC 2024
On Wed, Jul 31, 2024 at 04:31:01PM -0600, Cavitt, Jonathan wrote:
> -----Original Message-----
> From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of Matthew Brost
> Sent: Wednesday, July 31, 2024 2:32 PM
> To: intel-xe at lists.freedesktop.org; dri-devel at lists.freedesktop.org
> Cc: maarten.lankhorst at linux.intel.com; Vivi, Rodrigo <rodrigo.vivi at intel.com>
> Subject: [PATCH v4 3/3] drm/xe: Faster devcoredump
> >
> > 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.
> >
> > 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)
> > v3:
> > - Kernel doc
> >
> > 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 | 112 ++++++++++++++++------
> > drivers/gpu/drm/xe/xe_devcoredump_types.h | 4 +
> > 2 files changed, 85 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
> > index d8d8ca2c19d3..b802a35c22f2 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)
> > -{
> > - 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)
> > +static ssize_t __xe_devcoredump_read(char *buffer, size_t count,
> > + struct xe_devcoredump *coredump)
> > {
> > - 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);
> > @@ -131,13 +112,86 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
> > drm_printf(&p, "\n**** VM state ****\n");
> > xe_vm_snapshot_print(coredump->snapshot.vm, &p);
> >
> > - return count - iter.remain;
> > + return 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);
> > +
> > + /* Calculate devcoredump size */
> > + ss->read_data_size = __xe_devcoredump_read(NULL, INT_MAX, coredump);
> > +
> > + ss->read_data = kvmalloc(ss->read_data_size, GFP_USER);
> > + if (!ss->read_data)
> > + return;
> > +
> > + __xe_devcoredump_read(ss->read_data, ss->read_data_size, 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 +199,8 @@ 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 +309,5 @@ int xe_devcoredump_init(struct xe_device *xe)
> > {
> > return devm_add_action_or_reset(xe->drm.dev, xe_driver_devcoredump_fini, &xe->drm);
> > }
> > +
> > #endif
> > diff --git a/drivers/gpu/drm/xe/xe_devcoredump_types.h b/drivers/gpu/drm/xe/xe_devcoredump_types.h
> > index 923cdf72a816..0298037edae4 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 */
> > + ssize_t read_data_size;
> > + /** @read_data: Read data */
> > + void *read_data;
>
> Perhaps the data size and read data can be stapled together under the same
> struct?
>
> struct {
> ssize_t size;
> void *data;
> } read_data;
>
Yes, I like this better. Will change.
Matt
> It's not that big of a deal if this is untouched, just something to consider.
> Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
> -Jonathan Cavitt
>
> > };
> >
> > /**
> > --
> > 2.34.1
> >
> >
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