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mm/slab: allow __GFP_NOMEMALLOC and __GFP_NOWARN for kmalloc_nolock()

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The two flags are added internally so there's no point for warning if
they are passed by the caller as well, so allow them. This will allow
simplifying obj_ext allocation under kmalloc_nolock().

Also it's not necessary to have the extra alloc_gfp variable for adding
the two flags. The original gfp_flags parameter is not used anywhere
except for the warning. So remove alloc_gfp and directly modify and use
gfp_flags everywhere.

Link: https://patch.msgid.link/20260610-slab_alloc_flags-v2-13-7190909db118@kernel.org
Reviewed-by: Hao Li <hao.li@linux.dev>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Harry Yoo (Oracle) <harry@kernel.org>
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
This commit is contained in:
Vlastimil Babka (SUSE) 2026-06-10 17:40:15 +02:00
parent d659903674
commit 6dbded46e4
2 changed files with 12 additions and 10 deletions
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3
include/linux/slab.h
View File

@ -1040,7 +1040,8 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in
* kmalloc_nolock - Allocate an object of given size from any context.
* @size: size to allocate
* @gfp_flags: GFP flags. Only __GFP_ACCOUNT, __GFP_ZERO, __GFP_NO_OBJ_EXT
* allowed.
* allowed. Also __GFP_NOWARN and __GFP_NOMEMALLOC are allowed but added
* internally thus not necessary.
* @node: node number of the target node.
*
* Return: pointer to the new object or NULL in case of error.

19
mm/slub.c
View File

@ -5387,7 +5387,6 @@ EXPORT_SYMBOL(__kmalloc_noprof);
void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, int node)
{
gfp_t alloc_gfp = __GFP_NOWARN | __GFP_NOMEMALLOC | gfp_flags;
size_t orig_size = size;
unsigned int alloc_flags = SLAB_ALLOC_NOLOCK;
struct kmem_cache *s;
@ -5400,7 +5399,9 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in
};
VM_WARN_ON_ONCE(gfp_flags & ~(__GFP_ACCOUNT | __GFP_ZERO |
__GFP_NO_OBJ_EXT));
__GFP_NO_OBJ_EXT | __GFP_NOWARN | __GFP_NOMEMALLOC));
gfp_flags |= __GFP_NOWARN | __GFP_NOMEMALLOC;
if (unlikely(!size))
return ZERO_SIZE_PTR;
@ -5419,7 +5420,7 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in
retry:
if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
return NULL;
s = kmalloc_slab(size, NULL, alloc_gfp, PASS_TOKEN_PARAM(token));
s = kmalloc_slab(size, NULL, gfp_flags, PASS_TOKEN_PARAM(token));
if (!(s->flags & __CMPXCHG_DOUBLE) && !kmem_cache_debug(s))
/*
@ -5433,7 +5434,7 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in
*/
return NULL;
ret = alloc_from_pcs(s, alloc_gfp, alloc_flags, node);
ret = alloc_from_pcs(s, gfp_flags, alloc_flags, node);
if (ret)
goto success;
@ -5443,7 +5444,7 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in
* kfence_alloc. Hence call __slab_alloc_node() (at most twice)
* and slab_post_alloc_hook() directly.
*/
ret = __slab_alloc_node(s, alloc_gfp, node, &ac);
ret = __slab_alloc_node(s, gfp_flags, node, &ac);
/*
* It's possible we failed due to trylock as we preempted someone with
@ -5456,8 +5457,8 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in
size = s->object_size + 1;
/*
* Another alternative is to
* if (memcg) alloc_gfp &= ~__GFP_ACCOUNT;
* else if (!memcg) alloc_gfp |= __GFP_ACCOUNT;
* if (memcg) gfp_flags &= ~__GFP_ACCOUNT;
* else if (!memcg) gfp_flags |= __GFP_ACCOUNT;
* to retry from bucket of the same size.
*/
can_retry = false;
@ -5466,9 +5467,9 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in
success:
maybe_wipe_obj_freeptr(s, ret);
slab_post_alloc_hook(s, alloc_gfp, 1, &ret, &ac);
slab_post_alloc_hook(s, gfp_flags, 1, &ret, &ac);
ret = kasan_kmalloc(s, ret, orig_size, alloc_gfp);
ret = kasan_kmalloc(s, ret, orig_size, gfp_flags);
return ret;
}
EXPORT_SYMBOL_GPL(_kmalloc_nolock_noprof);