From: Thomas Hellström Date: Tue, 17 Mar 2026 14:18:55 +0000 (+0100) Subject: drm/ttm: Avoid invoking the OOM killer when reading back swapped content X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c6135f67aa37a4a744869f726d706bda091e6dfa;p=thirdparty%2Flinux.git drm/ttm: Avoid invoking the OOM killer when reading back swapped content In situations where the system is very short on RAM, the shmem readback from swap-space may invoke the OOM killer. However, since this might be a recoverable situation where the caller is indicating this by setting struct ttm_operation_ctx::gfp_retry_mayfail to true, adjust the gfp value used by the allocation accordingly. Signed-off-by: Thomas Hellström Reviewed-by: Maarten Lankhorst Acked-by: Christian König Link: https://patch.msgid.link/20260317141856.237876-3-thomas.hellstrom@linux.intel.com --- diff --git a/drivers/gpu/drm/ttm/ttm_backup.c b/drivers/gpu/drm/ttm/ttm_backup.c index 6bd4c123d94cd..81df4cb5606b4 100644 --- a/drivers/gpu/drm/ttm/ttm_backup.c +++ b/drivers/gpu/drm/ttm/ttm_backup.c @@ -44,18 +44,20 @@ void ttm_backup_drop(struct file *backup, pgoff_t handle) * @dst: The struct page to copy into. * @handle: The handle returned when the page was backed up. * @intr: Try to perform waits interruptible or at least killable. + * @additional_gfp: GFP mask to add to the default GFP mask if any. * * Return: 0 on success, Negative error code on failure, notably * -EINTR if @intr was set to true and a signal is pending. */ int ttm_backup_copy_page(struct file *backup, struct page *dst, - pgoff_t handle, bool intr) + pgoff_t handle, bool intr, gfp_t additional_gfp) { struct address_space *mapping = backup->f_mapping; struct folio *from_folio; pgoff_t idx = ttm_backup_handle_to_shmem_idx(handle); - from_folio = shmem_read_folio(mapping, idx); + from_folio = shmem_read_folio_gfp(mapping, idx, mapping_gfp_mask(mapping) + | additional_gfp); if (IS_ERR(from_folio)) return PTR_ERR(from_folio); diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c index 8fa9e09f6ee59..aa41099c5ecfc 100644 --- a/drivers/gpu/drm/ttm/ttm_pool.c +++ b/drivers/gpu/drm/ttm/ttm_pool.c @@ -530,6 +530,8 @@ static int ttm_pool_restore_commit(struct ttm_pool_tt_restore *restore, p = first_page[i]; if (ttm_backup_page_ptr_is_handle(p)) { unsigned long handle = ttm_backup_page_ptr_to_handle(p); + gfp_t additional_gfp = ctx->gfp_retry_mayfail ? + __GFP_RETRY_MAYFAIL | __GFP_NOWARN : 0; if (IS_ENABLED(CONFIG_FAULT_INJECTION) && ctx->interruptible && should_fail(&backup_fault_inject, 1)) { @@ -543,7 +545,8 @@ static int ttm_pool_restore_commit(struct ttm_pool_tt_restore *restore, } ret = ttm_backup_copy_page(backup, restore->alloced_page + i, - handle, ctx->interruptible); + handle, ctx->interruptible, + additional_gfp); if (ret) break; diff --git a/include/drm/ttm/ttm_backup.h b/include/drm/ttm/ttm_backup.h index c33cba111171f..29b9c855af779 100644 --- a/include/drm/ttm/ttm_backup.h +++ b/include/drm/ttm/ttm_backup.h @@ -56,7 +56,7 @@ ttm_backup_page_ptr_to_handle(const struct page *page) void ttm_backup_drop(struct file *backup, pgoff_t handle); int ttm_backup_copy_page(struct file *backup, struct page *dst, - pgoff_t handle, bool intr); + pgoff_t handle, bool intr, gfp_t additional_gfp); s64 ttm_backup_backup_page(struct file *backup, struct page *page,