On Tue, Aug 12, 2025 at 09:52:25PM +0800, Qianfeng Rong wrote:
> Commit 16f5dfbc851b ("gfp: include __GFP_NOWARN in GFP_NOWAIT") made
> GFP_NOWAIT implicitly include __GFP_NOWARN.
>
> Therefore, explicit __GFP_NOWARN combined with GFP_NOWAIT (e.g.,
> `GFP_NOWAIT | __GFP_NOWARN`) is now redundant. Let's clean up these
> redundant flags across subsystems.
>
> No functional changes.
>
> Reviewed-by: Harry Yoo <harry.yoo@xxxxxxxxxx>
> Signed-off-by: Qianfeng Rong <rongqianfeng@xxxxxxxx>
LGTM, I wonder if there are other such redundancies in the kernel?
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> ---
> v1->v2:
> - Added a modification to remove redundant __GFP_NOWARN in
> mm/damon/ops-common.c
> ---
> mm/damon/ops-common.c | 2 +-
> mm/filemap.c | 2 +-
> mm/mmu_gather.c | 4 ++--
> mm/rmap.c | 2 +-
> mm/vmalloc.c | 2 +-
> 5 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c
> index 99321ff5cb92..b43595730f08 100644
> --- a/mm/damon/ops-common.c
> +++ b/mm/damon/ops-common.c
> @@ -303,7 +303,7 @@ static unsigned int __damon_migrate_folio_list(
> * instead of migrated.
> */
> .gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) |
> - __GFP_NOWARN | __GFP_NOMEMALLOC | GFP_NOWAIT,
> + __GFP_NOMEMALLOC | GFP_NOWAIT,
> .nid = target_nid,
> };
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 4e5c9544fee4..c21e98657e0b 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -1961,7 +1961,7 @@ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
> gfp &= ~__GFP_FS;
> if (fgp_flags & FGP_NOWAIT) {
> gfp &= ~GFP_KERNEL;
> - gfp |= GFP_NOWAIT | __GFP_NOWARN;
> + gfp |= GFP_NOWAIT;
> }
> if (WARN_ON_ONCE(!(fgp_flags & (FGP_LOCK | FGP_FOR_MMAP))))
> fgp_flags |= FGP_LOCK;
> diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
> index b49cc6385f1f..374aa6f021c6 100644
> --- a/mm/mmu_gather.c
> +++ b/mm/mmu_gather.c
> @@ -32,7 +32,7 @@ static bool tlb_next_batch(struct mmu_gather *tlb)
> if (tlb->batch_count == MAX_GATHER_BATCH_COUNT)
> return false;
>
> - batch = (void *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
> + batch = (void *)__get_free_page(GFP_NOWAIT);
> if (!batch)
> return false;
>
> @@ -364,7 +364,7 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
> struct mmu_table_batch **batch = &tlb->batch;
>
> if (*batch == NULL) {
> - *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
> + *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT);
> if (*batch == NULL) {
> tlb_table_invalidate(tlb);
> tlb_remove_table_one(table);
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 568198e9efc2..7baa7385e1ce 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -285,7 +285,7 @@ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src)
> list_for_each_entry_reverse(pavc, &src->anon_vma_chain, same_vma) {
> struct anon_vma *anon_vma;
>
> - avc = anon_vma_chain_alloc(GFP_NOWAIT | __GFP_NOWARN);
> + avc = anon_vma_chain_alloc(GFP_NOWAIT);
> if (unlikely(!avc)) {
> unlock_anon_vma_root(root);
> root = NULL;
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 6dbcdceecae1..90c3de1a0417 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -5177,7 +5177,7 @@ static void vmap_init_nodes(void)
> int n = clamp_t(unsigned int, num_possible_cpus(), 1, 128);
>
> if (n > 1) {
> - vn = kmalloc_array(n, sizeof(*vn), GFP_NOWAIT | __GFP_NOWARN);
> + vn = kmalloc_array(n, sizeof(*vn), GFP_NOWAIT);
> if (vn) {
> /* Node partition is 16 pages. */
> vmap_zone_size = (1 << 4) * PAGE_SIZE;
> --
> 2.34.1
>
