linux.git/include/linux/mempool.h, branch v7.2-rc1

mm: simplify the mempool_alloc_bulk API

2026-06-03T16:20:47+00:00

The mempool_alloc_bulk was modelled after the alloc_pages_bulk API,
including some misunderstanding of it.

Remove checking for NULL slots in the array, as alloc_pages_bulk and
kmem_cache_alloc_bulk always fill the array from the beginning and thus
we know the offset of the first failing allocation.  This removes support
for working well with alloc_pages_bulk used to refill page arrays that
might have an entry removed from in the middle, but that is only used by
sunrpc and hopefully on it's way out.

Also remove the allocated parameter as it is redundant because the caller
can simply specific and offset into the entries array.

Signed-off-by: Christoph Hellwig 
Link: https://patch.msgid.link/20260602160038.3976341-1-hch@lst.de
Signed-off-by: Vlastimil Babka (SUSE)

mempool: de-typedef

2025-11-23T11:30:40+00:00

Switch all uses of the deprecated mempool_t typedef in the core mempool
code to use struct mempool instead.

Signed-off-by: Christoph Hellwig 
Link: https://patch.msgid.link/20251113084022.1255121-11-hch@lst.de
Signed-off-by: Vlastimil Babka

mempool: remove mempool_{init,create}_kvmalloc_pool

2025-11-23T11:30:40+00:00

This was added for bcachefs and is unused now.

Signed-off-by: Christoph Hellwig 
Link: https://patch.msgid.link/20251113084022.1255121-10-hch@lst.de
Signed-off-by: Vlastimil Babka

mempool: add mempool_{alloc,free}_bulk

2025-11-23T11:30:36+00:00

Add a version of the mempool allocator that works for batch allocations
of multiple objects.  Calling mempool_alloc in a loop is not safe because
it could deadlock if multiple threads are performing such an allocation
at the same time.

As an extra benefit the interface is build so that the same array can be
used for alloc_pages_bulk / release_pages so that at least for page
backed mempools the fast path can use a nice batch optimization.

Note that mempool_alloc_bulk does not take a gfp_mask argument as it
must always be able to sleep and doesn't support any non-trivial
modifiers.  NOFO or NOIO constrainst must be set through the scoped API.

Signed-off-by: Christoph Hellwig 
Link: https://patch.msgid.link/20251113084022.1255121-8-hch@lst.de
Signed-off-by: Vlastimil Babka

mempool: rename struct mempool_s to struct mempool

2025-09-13T23:54:59+00:00

Drop the pointless _s prefix and align to the usual struct naming to
prepare for actually using the struct instead of the typedef so that
random headers don't need to include mempool.h for just having a pointer
to the mempool.

Link: https://lkml.kernel.org/r/20250812083105.371295-1-hch@lst.de
Signed-off-by: Christoph Hellwig 
Reviewed-by: Harry Yoo 
Reviewed-by: Vlastimil Babka 
Cc: Christoph Lameter (Ampere) 
Cc: David Rientjes 
Cc: Roman Gushchin 
Signed-off-by: Andrew Morton

mempool: hook up to memory allocation profiling

2024-04-26T03:55:56+00:00

This adds hooks to mempools for correctly annotating mempool-backed
allocations at the correct source line, so they show up correctly in
/sys/kernel/debug/allocations.

Various inline functions are converted to wrappers so that we can invoke
alloc_hooks() in fewer places.

[surenb@google.com: undo _noprof additions in the documentation]
  Link: https://lkml.kernel.org/r/20240326231453.1206227-4-surenb@google.com
[surenb@google.com: add missing mempool_create_node documentation]
  Link: https://lkml.kernel.org/r/20240402180835.1661905-1-surenb@google.com
Link: https://lkml.kernel.org/r/20240321163705.3067592-27-surenb@google.com
Signed-off-by: Kent Overstreet 
Signed-off-by: Suren Baghdasaryan 
Tested-by: Kees Cook 
Cc: Alexander Viro 
Cc: Alex Gaynor 
Cc: Alice Ryhl 
Cc: Andreas Hindborg 
Cc: Benno Lossin 
Cc: "Björn Roy Baron" 
Cc: Boqun Feng 
Cc: Christoph Lameter 
Cc: Dennis Zhou 
Cc: Gary Guo 
Cc: Miguel Ojeda 
Cc: Pasha Tatashin 
Cc: Peter Zijlstra 
Cc: Tejun Heo 
Cc: Vlastimil Babka 
Cc: Wedson Almeida Filho 
Signed-off-by: Andrew Morton

mempool: kvmalloc pool

2024-03-13T22:38:13+00:00

Add mempool_init_kvmalloc_pool() and mempool_create_kvmalloc_pool(),
which wrap kvmalloc() instead of kmalloc() - kmalloc() with a vmalloc()
fallback.

This is part of a bcachefs cleanup - dropping an internal kvpmalloc()
helper (which predates kvmalloc()) along with mempool helpers; this
replaces the bcachefs-private kvpmalloc_pool.

Signed-off-by: Kent Overstreet 
Cc: linux-mm@kvack.org

mempool: introduce mempool_use_prealloc_only

2023-12-29T19:58:39+00:00

Introduce a new mempool_alloc_preallocated API that asks the mempool to
only use the elements preallocated during the mempool's creation when
allocating and to not attempt allocating new ones from the underlying
allocator.

This API is required to test the KASAN poisoning/unpoisoning functionality
in KASAN tests, but it might be also useful on its own.

Link: https://lkml.kernel.org/r/a14d809dbdfd04cc33bcacc632fee2abd6b83c00.1703024586.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 

Cc: Alexander Lobakin 
Cc: Alexander Potapenko 
Cc: Andrey Ryabinin 
Cc: Breno Leitao 
Cc: Dmitry Vyukov 
Cc: Evgenii Stepanov 
Cc: Marco Elver 
Signed-off-by: Andrew Morton

mempool: introduce mempool_is_saturated

2022-11-16T16:44:26+00:00

Introduce a helper mempool_is_saturated(), which tells if the mempool is
under-filled or not. We need it to figure out whether it should be
freed right into the mempool or could be cached with top level caches.

Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/636aed30be8c35d78f45e244998bc6209283cccc.1667384020.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe

mempool: Add mempool_init()/mempool_exit()

2018-05-14T19:14:23+00:00

Allows mempools to be embedded in other structs, getting rid of a
pointer indirection from allocation fastpaths.

mempool_exit() is safe to call on an uninitialized but zeroed mempool.

Signed-off-by: Kent Overstreet 
Signed-off-by: Jens Axboe