Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] drm: memory waste in drm_exec due to unaligned kvmalloc size --
commit c9e9f41b6b460bbc9dee72fd6820d00dc1915559 Author: Matthew Brost <[email protected]> drm/exec: track the first few locked objects inline This commit adds tracking for the first few locked objects inline within the drm_exec structure. This avoids early allocations and prevents -ENOMEM failures on paths that only need to lock a few objects. Link: https://sashiko.dev/#/patchset/20261001220632.3190896-1-matthew.brost%40intel.com > diff --git a/drivers/gpu/drm/drm_exec.c b/drivers/gpu/drm/drm_exec.c > --- a/drivers/gpu/drm/drm_exec.c > +++ b/drivers/gpu/drm/drm_exec.c [ ... ] > @@ -140,9 +148,16 @@ static int drm_exec_obj_locked(struct drm_exec *exec, > { > if (unlikely(exec->num_objects == exec->max_objects)) { > size_t size = exec->max_objects * sizeof(void *); > - void *tmp; > - > - tmp = kvrealloc(exec->objects, size + PAGE_SIZE, GFP_KERNEL); > + struct drm_gem_object **tmp; > + > + if (exec->objects == exec->inline_objects) { > + tmp = kvmalloc(size + PAGE_SIZE, GFP_KERNEL); [Severity: Medium] When falling back from the inline storage, size is 64 bytes (8 pointers). The code requests kvmalloc(64 + 4096), which is 4160 bytes. Does this cause the slab allocator to round up to the kmalloc-8k cache, wasting nearly half the allocation? > + if (tmp) > + memcpy(tmp, exec->objects, size); > + } else { > + tmp = kvrealloc(exec->objects, size + PAGE_SIZE, > + GFP_KERNEL); > + } > if (!tmp) > return -ENOMEM; > > exec->objects = tmp; > exec->max_objects += PAGE_SIZE / sizeof(void *); [Severity: Medium] Since max_objects started at 8, adding PAGE_SIZE / sizeof(void *) makes max_objects 520. When the array grows again, size will be 4160 and kvrealloc will request 8256 bytes, forcing kmalloc-16k. Does this continue to waste memory at every growth step because the total object count remains unaligned to the page size? -- Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=1
