On Mon, Jul 29, 2024 at 03:01:27PM +0100, Dave Martin wrote:
> Since v6.8 the definition of GFP_NOWAIT has implied __GFP_NOWARN,
> so it is now redundant to add this flag explicitly.
>
> Update the docs to match, and emphasise the need for a fallback
> when using GFP_NOWAIT.
>
> Fixes: 16f5dfbc851b ("gfp: include __GFP_NOWARN in GFP_NOWAIT")
> Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
> ---
>
> Based on: v6.11-rc1
>
> This change also evaporates the apparent typo of __GFP_NOWARN without
> the underscores in the documentation, but that doesn't really feel like
> it merits a dedicated patch.
>
> Not sure if this really merits a Fixes tag, but the docmuentation
> update might as well be picked into trees that have the corresponding
> code change.
>
> ---
> Documentation/core-api/memory-allocation.rst | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/core-api/memory-allocation.rst b/Documentation/core-api/memory-allocation.rst
> index 8b84eb4bdae7..0f19dd524323 100644
> --- a/Documentation/core-api/memory-allocation.rst
> +++ b/Documentation/core-api/memory-allocation.rst
> @@ -45,8 +45,9 @@ here we briefly outline their recommended usage:
> * If the allocation is performed from an atomic context, e.g interrupt
> handler, use ``GFP_NOWAIT``. This flag prevents direct reclaim and
> IO or filesystem operations. Consequently, under memory pressure
> - ``GFP_NOWAIT`` allocation is likely to fail. Allocations which
> - have a reasonable fallback should be using ``GFP_NOWARN``.
> + ``GFP_NOWAIT`` allocation is likely to fail. Users of this flag need
> + to provide a suitable fallback to cope with such failures where
> + appropriate.
> * If you think that accessing memory reserves is justified and the kernel
> will be stressed unless allocation succeeds, you may use ``GFP_ATOMIC``.
> * Untrusted allocations triggered from userspace should be a subject
>
> base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b
> --
> 2.34.1
>
>
--
Sincerely yours,
Mike.
