On 6/18/23 20:11, Ira Weiny wrote:
Sumitra Sharma wrote:
kmap() has been deprecated in favor of the kmap_local_page()
due to high cost, restricted mapping space, the overhead of a
global lock for synchronization, and making the process sleep
in the absence of free slots.
kmap_local_page() is faster than kmap() and offers thread-local
and CPU-local mappings, take pagefaults in a local kmap region
and preserves preemption by saving the mappings of outgoing tasks
and restoring those of the incoming one during a context switch.
The mapping is kept thread local in the function
“i915_vma_coredump_create” in i915_gpu_error.c
Therefore, replace kmap() with kmap_local_page().
Suggested-by: Ira Weiny <ira.weiny@xxxxxxxxx>
NIT: No need for the line break between Suggested-by and your signed off line.
Signed-off-by: Sumitra Sharma <sumitraartsy@xxxxxxxxx>
---
Changes in v2:
- Replace kmap() with kmap_local_page().
Generally it is customary to attribute a change like this to those who
suggested it in a V1 review.
For example:
- Tvrtko/Thomas: Use kmap_local_page() instead of page_address()
Also I don't see Thomas on the new email list. Since he took the time to
review V1 he might want to check this version out. I've added him to the
'To:' list.
Thanks.
Also a link to V1 is nice. B4 formats it like this:
- Link to v1: https://lore.kernel.org/all/20230614123556.GA381200@xxxxxxxxxxx/
All that said the code looks good to me. So with the above changes.
Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
LGTM. Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
- Change commit subject and message.
drivers/gpu/drm/i915/i915_gpu_error.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index f020c0086fbc..bc41500eedf5 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1164,9 +1164,9 @@ i915_vma_coredump_create(const struct intel_gt *gt,
drm_clflush_pages(&page, 1);
- s = kmap(page);
+ s = kmap_local_page(page);
ret = compress_page(compress, s, dst, false);
- kunmap(page);
+ kunmap_local(s);
drm_clflush_pages(&page, 1);
--
2.25.1
