Add a new entry in stats to for svm page faults. If CONFIG_DEBUG_FS is
enabled, the count can be viewed with per GT stat debugfs file.
This is similar to what is already in place for vma page faults.
Example output:
cat /sys/kernel/debug/dri/0/gt0/stats
svm_pagefault_count: 6
tlb_inval_count: 78
vma_pagefault_count: 0
vma_pagefault_kb: 0
v2: Fix build with CONFIG_DRM_GPUSVM disabled
v3: Update argument in kernel doc
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250312092749.164232-1-francois.dugast@intel.com
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
The stats counters are now used for things like counting the VMA
bytes during page faults. During workload execution, the counter
value can grow fast and easily reach the atomic int limit, in
which case it overflows. To make this less likely to happen, push
the limit by switching to 64b atomic to store the counter value.
Overhead is very small as there are only 3 stat entries per GT as
of now, and stats are only enabled with CONFIG_DEBUG_FS.
Suggested-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250225195902.1247100-2-francois.dugast@intel.com
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Add new entries in stats for vma page faults. If CONFIG_DEBUG_FS is
enabled, the count and number of bytes can be viewed per GT in the
stat debugfs file. This helps when testing, to confirm page faults
have been triggered as expected. It also helps when looking at the
performance impact of page faults. Data is simply collected when
entering the page fault handler so there is no indication whether
it completed successfully, with or without retries, etc.
Example output:
cat /sys/kernel/debug/dri/0/gt0/stats
tlb_inval_count: 129
vma_pagefault_count: 12
vma_pagefault_bytes: 98304
v2: Rebase
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250206134551.1321265-1-francois.dugast@intel.com
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
