Hi, Could you please help review this patch? Thanks, zackary
On Thu, Aug 06, 2026 at 09:21:41PM +0800, Zhaoyu Liu wrote: > The second loop in drm_pagemap_migrate_to_devmem() checks > `page_pgmap(src_page) == pagemap && !can_migrate_same_pagemap` to skip > pages already on the target pagemap. However, this condition is always > false at this point: if can_migrate_same_pagemap is false and any own > pages exist, the first loop already returns -EBUSY before reaching here. > > v2: > - Skip the no-op migrate_vma_pages() when all pages already reside on > the target pagemap. > > Signed-off-by: Zhaoyu Liu <[email protected]> > --- > drivers/gpu/drm/drm_pagemap.c | 21 ++++++--------------- > 1 file changed, 6 insertions(+), 15 deletions(-) > > diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c > index 15c78eca180b..64922b944092 100644 > --- a/drivers/gpu/drm/drm_pagemap.c > +++ b/drivers/gpu/drm/drm_pagemap.c > @@ -698,7 +698,7 @@ int drm_pagemap_migrate_to_devmem(struct > drm_pagemap_devmem *devmem_allocation, > * nothing. Raced or unknown device pages. > */ > err = -EBUSY; > - goto err_aborted_migration; > + goto direct_finalize; > } > > /* Count device-private pages to migrate */ > @@ -719,19 +719,17 @@ int drm_pagemap_migrate_to_devmem(struct > drm_pagemap_devmem *devmem_allocation, > if (own_pages == npages) { > err = 0; > drm_dbg(dpagemap->drm, "Migration wasn't necessary.\n"); > - goto err_aborted_migration; > + goto direct_finalize; > } else if (own_pages && !mdetails->can_migrate_same_pagemap) { > err = -EBUSY; > drm_dbg(dpagemap->drm, "Migration aborted due to > fragmentation.\n"); > - goto err_aborted_migration; > + goto direct_finalize; > } > > err = ops->populate_devmem_pfn(devmem_allocation, npages, migrate.dst); > if (err) > goto err_aborted_migration; > > - own_pages = 0; > - > for (i = 0; i < npages;) { > unsigned long j; > struct page *page = pfn_to_page(migrate.dst[i]); > @@ -744,12 +742,7 @@ int drm_pagemap_migrate_to_devmem(struct > drm_pagemap_devmem *devmem_allocation, > struct drm_pagemap_zdd *src_zdd = > drm_pagemap_page_zone_device_data(src_page); > > - if (page_pgmap(src_page) == pagemap && > - !mdetails->can_migrate_same_pagemap) { > - migrate.dst[i] = 0; > - own_pages++; > - goto next; > - } > + /* Own or peer device private page */ > cur.dpagemap = src_zdd->dpagemap; > cur.ops = src_zdd->devmem_allocation->ops; > cur.device = cur.dpagemap->drm->dev; > @@ -786,7 +779,6 @@ int drm_pagemap_migrate_to_devmem(struct > drm_pagemap_devmem *devmem_allocation, > goto err_finalize; > } > > -next: > i += NR_PAGES(order); > } > > @@ -797,8 +789,6 @@ int drm_pagemap_migrate_to_devmem(struct > drm_pagemap_devmem *devmem_allocation, > if (err) > goto err_finalize; > > - drm_WARN_ON(dpagemap->drm, !!own_pages); > - > dma_fence_put(devmem_allocation->pre_migrate_fence); > devmem_allocation->pre_migrate_fence = NULL; > > @@ -822,11 +812,12 @@ int drm_pagemap_migrate_to_devmem(struct > drm_pagemap_devmem *devmem_allocation, > i += nr_pages; > } > > - if (!err && migrated_pages < npages - own_pages) { > + if (!err && migrated_pages < npages) { > drm_dbg(dpagemap->drm, "Raced while finalizing migration.\n"); > err = -EBUSY; > } > > +direct_finalize: > migrate_vma_finalize(&migrate); > err_free: > drm_pagemap_zdd_put(zdd); > -- > 2.34.1
