mm/slab: add alloc_flags to slab_alloc_context

Add alloc_flags as a new field to the slab_alloc_context helper struct,
so we can pass it to more functions in the slab implementation without
adding another function parameter.

Start checking them via alloc_flags_allow_spinning() in
alloc_single_from_new_slab() (where we can drop the allow_spin
parameter), ___slab_alloc(), get_from_partial_node() and
get_from_any_partial(). This further reduces false-positive
spinning-not-allowed from allocations that are not kmalloc_nolock() but
lack __GFP_RECLAIM flags.

_kmalloc_nolock_noprof() initializes ac.alloc_flags using its flags that
are SLAB_ALLOC_NOLOCK. slab_alloc_node() and __kmem_cache_alloc_bulk()
are not reachable from kmalloc_nolock() and all their callers expect
spinning to be allowed, so they can use SLAB_ALLOC_DEFAULT. This is
temporary as the scope of slab_alloc_context will further move to the
callers, making the alloc_flags usage more obvious.

Also change how trynode_flags are constructed in ___slab_alloc() to
achieve the same "do not upgrade to GFP_NOWAIT" by using masking instead
of checking allow_spin. We need to do that because we now determine
allow_spin from alloc_flags, and would otherwise start to upgrade e.g.
kmalloc() allocations without __GFP_KSWAPD_RECLAIM (that however do
allow spinning) to GFP_NOWAIT, thus including __GFP_KSWAPD_RECLAIM.

During the masking keep also existing __GFP_NOMEMALLOC (pointed out by
Sashiko) and __GFP_ACCOUNT. Previously the hardcoded GFP_NOWAIT would
eliminate them, but it's not a big problem that would need a separate
fix.

Link: https://patch.msgid.link/20260610-slab_alloc_flags-v2-6-7190909db118@kernel.org
Reviewed-by: Harry Yoo (Oracle) <harry@kernel.org>
Reviewed-by: Hao Li <hao.li@linux.dev>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>

0 files changed, 0 insertions, 0 deletions