headers/deps: mm: Split <linux/gfp_types.h> out of <linux/gfp.h>

#ifndef __LINUX_GFP_H

#define __LINUX_GFP_H

#include <linux/gfp_types.h>

#include <linux/mmzone.h>

#include <linux/topology.h>

/* The typedef is in types.h but we want the documentation here */

#if 0

/**

 * typedef gfp_t - Memory allocation flags.

 *

 * GFP flags are commonly used throughout Linux to indicate how memory

 * should be allocated.  The GFP acronym stands for get_free_pages(),

 * the underlying memory allocation function.  Not every GFP flag is

 * supported by every function which may allocate memory.  Most users

 * will want to use a plain ``GFP_KERNEL``.

 */

typedef unsigned int __bitwise gfp_t;

#endif

struct vm_area_struct;

/*

 * In case of changes, please don't forget to update

 * include/trace/events/mmflags.h and tools/perf/builtin-kmem.c

 */

/* Plain integer GFP bitmasks. Do not use this directly. */

#define ___GFP_DMA		0x01u

#define ___GFP_HIGHMEM		0x02u

#define ___GFP_DMA32		0x04u

#define ___GFP_MOVABLE		0x08u

#define ___GFP_RECLAIMABLE	0x10u

#define ___GFP_HIGH		0x20u

#define ___GFP_IO		0x40u

#define ___GFP_FS		0x80u

#define ___GFP_ZERO		0x100u

#define ___GFP_ATOMIC		0x200u

#define ___GFP_DIRECT_RECLAIM	0x400u

#define ___GFP_KSWAPD_RECLAIM	0x800u

#define ___GFP_WRITE		0x1000u

#define ___GFP_NOWARN		0x2000u

#define ___GFP_RETRY_MAYFAIL	0x4000u

#define ___GFP_NOFAIL		0x8000u

#define ___GFP_NORETRY		0x10000u

#define ___GFP_MEMALLOC		0x20000u

#define ___GFP_COMP		0x40000u

#define ___GFP_NOMEMALLOC	0x80000u

#define ___GFP_HARDWALL		0x100000u

#define ___GFP_THISNODE		0x200000u

#define ___GFP_ACCOUNT		0x400000u

#define ___GFP_ZEROTAGS		0x800000u

#ifdef CONFIG_KASAN_HW_TAGS

#define ___GFP_SKIP_ZERO		0x1000000u

#define ___GFP_SKIP_KASAN_UNPOISON	0x2000000u

#define ___GFP_SKIP_KASAN_POISON	0x4000000u

#else

#define ___GFP_SKIP_ZERO		0

#define ___GFP_SKIP_KASAN_UNPOISON	0

#define ___GFP_SKIP_KASAN_POISON	0

#endif

#ifdef CONFIG_LOCKDEP

#define ___GFP_NOLOCKDEP	0x8000000u

#else

#define ___GFP_NOLOCKDEP	0

#endif

/* If the above are modified, __GFP_BITS_SHIFT may need updating */

/*

 * Physical address zone modifiers (see linux/mmzone.h - low four bits)

 *

 * Do not put any conditional on these. If necessary modify the definitions

 * without the underscores and use them consistently. The definitions here may

 * be used in bit comparisons.

 */

#define __GFP_DMA	((__force gfp_t)___GFP_DMA)

#define __GFP_HIGHMEM	((__force gfp_t)___GFP_HIGHMEM)

#define __GFP_DMA32	((__force gfp_t)___GFP_DMA32)

#define __GFP_MOVABLE	((__force gfp_t)___GFP_MOVABLE)  /* ZONE_MOVABLE allowed */

#define GFP_ZONEMASK	(__GFP_DMA|__GFP_HIGHMEM|__GFP_DMA32|__GFP_MOVABLE)

/**

 * DOC: Page mobility and placement hints

 *

 * Page mobility and placement hints

 * ---------------------------------

 *

 * These flags provide hints about how mobile the page is. Pages with similar

 * mobility are placed within the same pageblocks to minimise problems due

 * to external fragmentation.

 *

 * %__GFP_MOVABLE (also a zone modifier) indicates that the page can be

 * moved by page migration during memory compaction or can be reclaimed.

 *

 * %__GFP_RECLAIMABLE is used for slab allocations that specify

 * SLAB_RECLAIM_ACCOUNT and whose pages can be freed via shrinkers.

 *

 * %__GFP_WRITE indicates the caller intends to dirty the page. Where possible,

 * these pages will be spread between local zones to avoid all the dirty

 * pages being in one zone (fair zone allocation policy).

 *

 * %__GFP_HARDWALL enforces the cpuset memory allocation policy.

 *

 * %__GFP_THISNODE forces the allocation to be satisfied from the requested

 * node with no fallbacks or placement policy enforcements.

 *

 * %__GFP_ACCOUNT causes the allocation to be accounted to kmemcg.

 */

#define __GFP_RECLAIMABLE ((__force gfp_t)___GFP_RECLAIMABLE)

#define __GFP_WRITE	((__force gfp_t)___GFP_WRITE)

#define __GFP_HARDWALL   ((__force gfp_t)___GFP_HARDWALL)

#define __GFP_THISNODE	((__force gfp_t)___GFP_THISNODE)

#define __GFP_ACCOUNT	((__force gfp_t)___GFP_ACCOUNT)

/**

 * DOC: Watermark modifiers

 *

 * Watermark modifiers -- controls access to emergency reserves

 * ------------------------------------------------------------

 *

 * %__GFP_HIGH indicates that the caller is high-priority and that granting

 * the request is necessary before the system can make forward progress.

 * For example, creating an IO context to clean pages.

 *

 * %__GFP_ATOMIC indicates that the caller cannot reclaim or sleep and is

 * high priority. Users are typically interrupt handlers. This may be

 * used in conjunction with %__GFP_HIGH

 *

 * %__GFP_MEMALLOC allows access to all memory. This should only be used when

 * the caller guarantees the allocation will allow more memory to be freed

 * very shortly e.g. process exiting or swapping. Users either should

 * be the MM or co-ordinating closely with the VM (e.g. swap over NFS).

 * Users of this flag have to be extremely careful to not deplete the reserve

 * completely and implement a throttling mechanism which controls the

 * consumption of the reserve based on the amount of freed memory.

 * Usage of a pre-allocated pool (e.g. mempool) should be always considered

 * before using this flag.

 *

 * %__GFP_NOMEMALLOC is used to explicitly forbid access to emergency reserves.

 * This takes precedence over the %__GFP_MEMALLOC flag if both are set.

 */

#define __GFP_ATOMIC	((__force gfp_t)___GFP_ATOMIC)

#define __GFP_HIGH	((__force gfp_t)___GFP_HIGH)

#define __GFP_MEMALLOC	((__force gfp_t)___GFP_MEMALLOC)

#define __GFP_NOMEMALLOC ((__force gfp_t)___GFP_NOMEMALLOC)

/**

 * DOC: Reclaim modifiers

 *

 * Reclaim modifiers

 * -----------------

 * Please note that all the following flags are only applicable to sleepable

 * allocations (e.g. %GFP_NOWAIT and %GFP_ATOMIC will ignore them).

 *

 * %__GFP_IO can start physical IO.

 *

 * %__GFP_FS can call down to the low-level FS. Clearing the flag avoids the

 * allocator recursing into the filesystem which might already be holding

 * locks.

 *

 * %__GFP_DIRECT_RECLAIM indicates that the caller may enter direct reclaim.

 * This flag can be cleared to avoid unnecessary delays when a fallback

 * option is available.

 *

 * %__GFP_KSWAPD_RECLAIM indicates that the caller wants to wake kswapd when

 * the low watermark is reached and have it reclaim pages until the high

 * watermark is reached. A caller may wish to clear this flag when fallback

 * options are available and the reclaim is likely to disrupt the system. The

 * canonical example is THP allocation where a fallback is cheap but

 * reclaim/compaction may cause indirect stalls.

 *

 * %__GFP_RECLAIM is shorthand to allow/forbid both direct and kswapd reclaim.

 *

 * The default allocator behavior depends on the request size. We have a concept

 * of so called costly allocations (with order > %PAGE_ALLOC_COSTLY_ORDER).

 * !costly allocations are too essential to fail so they are implicitly

 * non-failing by default (with some exceptions like OOM victims might fail so

 * the caller still has to check for failures) while costly requests try to be

 * not disruptive and back off even without invoking the OOM killer.

 * The following three modifiers might be used to override some of these

 * implicit rules

 *

 * %__GFP_NORETRY: The VM implementation will try only very lightweight

 * memory direct reclaim to get some memory under memory pressure (thus

 * it can sleep). It will avoid disruptive actions like OOM killer. The

 * caller must handle the failure which is quite likely to happen under

 * heavy memory pressure. The flag is suitable when failure can easily be

 * handled at small cost, such as reduced throughput

 *

 * %__GFP_RETRY_MAYFAIL: The VM implementation will retry memory reclaim

 * procedures that have previously failed if there is some indication

 * that progress has been made else where.  It can wait for other

 * tasks to attempt high level approaches to freeing memory such as

 * compaction (which removes fragmentation) and page-out.

 * There is still a definite limit to the number of retries, but it is

 * a larger limit than with %__GFP_NORETRY.

 * Allocations with this flag may fail, but only when there is

 * genuinely little unused memory. While these allocations do not

 * directly trigger the OOM killer, their failure indicates that

 * the system is likely to need to use the OOM killer soon.  The

 * caller must handle failure, but can reasonably do so by failing

 * a higher-level request, or completing it only in a much less

 * efficient manner.

 * If the allocation does fail, and the caller is in a position to

 * free some non-essential memory, doing so could benefit the system

 * as a whole.

 *

 * %__GFP_NOFAIL: The VM implementation _must_ retry infinitely: the caller

 * cannot handle allocation failures. The allocation could block

 * indefinitely but will never return with failure. Testing for

 * failure is pointless.

 * New users should be evaluated carefully (and the flag should be

 * used only when there is no reasonable failure policy) but it is

 * definitely preferable to use the flag rather than opencode endless

 * loop around allocator.

 * Using this flag for costly allocations is _highly_ discouraged.

 */

#define __GFP_IO	((__force gfp_t)___GFP_IO)

#define __GFP_FS	((__force gfp_t)___GFP_FS)

#define __GFP_DIRECT_RECLAIM	((__force gfp_t)___GFP_DIRECT_RECLAIM) /* Caller can reclaim */

#define __GFP_KSWAPD_RECLAIM	((__force gfp_t)___GFP_KSWAPD_RECLAIM) /* kswapd can wake */

#define __GFP_RECLAIM ((__force gfp_t)(___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM))

#define __GFP_RETRY_MAYFAIL	((__force gfp_t)___GFP_RETRY_MAYFAIL)

#define __GFP_NOFAIL	((__force gfp_t)___GFP_NOFAIL)

#define __GFP_NORETRY	((__force gfp_t)___GFP_NORETRY)

/**

 * DOC: Action modifiers

 *

 * Action modifiers

 * ----------------

 *

 * %__GFP_NOWARN suppresses allocation failure reports.

 *

 * %__GFP_COMP address compound page metadata.

 *

 * %__GFP_ZERO returns a zeroed page on success.

 *

 * %__GFP_ZEROTAGS zeroes memory tags at allocation time if the memory itself

 * is being zeroed (either via __GFP_ZERO or via init_on_alloc, provided that

 * __GFP_SKIP_ZERO is not set). This flag is intended for optimization: setting

 * memory tags at the same time as zeroing memory has minimal additional

 * performace impact.

 *

 * %__GFP_SKIP_KASAN_UNPOISON makes KASAN skip unpoisoning on page allocation.

 * Only effective in HW_TAGS mode.

 *

 * %__GFP_SKIP_KASAN_POISON makes KASAN skip poisoning on page deallocation.

 * Typically, used for userspace pages. Only effective in HW_TAGS mode.

 */

#define __GFP_NOWARN	((__force gfp_t)___GFP_NOWARN)

#define __GFP_COMP	((__force gfp_t)___GFP_COMP)

#define __GFP_ZERO	((__force gfp_t)___GFP_ZERO)

#define __GFP_ZEROTAGS	((__force gfp_t)___GFP_ZEROTAGS)

#define __GFP_SKIP_ZERO ((__force gfp_t)___GFP_SKIP_ZERO)

#define __GFP_SKIP_KASAN_UNPOISON ((__force gfp_t)___GFP_SKIP_KASAN_UNPOISON)

#define __GFP_SKIP_KASAN_POISON   ((__force gfp_t)___GFP_SKIP_KASAN_POISON)

/* Disable lockdep for GFP context tracking */

#define __GFP_NOLOCKDEP ((__force gfp_t)___GFP_NOLOCKDEP)

/* Room for N __GFP_FOO bits */

#define __GFP_BITS_SHIFT (27 + IS_ENABLED(CONFIG_LOCKDEP))

#define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))

/**

 * DOC: Useful GFP flag combinations

 *

 * Useful GFP flag combinations

 * ----------------------------

 *

 * Useful GFP flag combinations that are commonly used. It is recommended

 * that subsystems start with one of these combinations and then set/clear

 * %__GFP_FOO flags as necessary.

 *

 * %GFP_ATOMIC users can not sleep and need the allocation to succeed. A lower

 * watermark is applied to allow access to "atomic reserves".

 * The current implementation doesn't support NMI and few other strict

 * non-preemptive contexts (e.g. raw_spin_lock). The same applies to %GFP_NOWAIT.

 *

 * %GFP_KERNEL is typical for kernel-internal allocations. The caller requires

 * %ZONE_NORMAL or a lower zone for direct access but can direct reclaim.

 *

 * %GFP_KERNEL_ACCOUNT is the same as GFP_KERNEL, except the allocation is

 * accounted to kmemcg.

 *

 * %GFP_NOWAIT is for kernel allocations that should not stall for direct

 * reclaim, start physical IO or use any filesystem callback.

 *

 * %GFP_NOIO will use direct reclaim to discard clean pages or slab pages

 * that do not require the starting of any physical IO.

 * Please try to avoid using this flag directly and instead use

 * memalloc_noio_{save,restore} to mark the whole scope which cannot

 * perform any IO with a short explanation why. All allocation requests

 * will inherit GFP_NOIO implicitly.

 *

 * %GFP_NOFS will use direct reclaim but will not use any filesystem interfaces.

 * Please try to avoid using this flag directly and instead use

 * memalloc_nofs_{save,restore} to mark the whole scope which cannot/shouldn't

 * recurse into the FS layer with a short explanation why. All allocation

 * requests will inherit GFP_NOFS implicitly.

 *

 * %GFP_USER is for userspace allocations that also need to be directly

 * accessibly by the kernel or hardware. It is typically used by hardware

 * for buffers that are mapped to userspace (e.g. graphics) that hardware

 * still must DMA to. cpuset limits are enforced for these allocations.

 *

 * %GFP_DMA exists for historical reasons and should be avoided where possible.

 * The flags indicates that the caller requires that the lowest zone be

 * used (%ZONE_DMA or 16M on x86-64). Ideally, this would be removed but

 * it would require careful auditing as some users really require it and

 * others use the flag to avoid lowmem reserves in %ZONE_DMA and treat the

 * lowest zone as a type of emergency reserve.

 *

 * %GFP_DMA32 is similar to %GFP_DMA except that the caller requires a 32-bit

 * address. Note that kmalloc(..., GFP_DMA32) does not return DMA32 memory

 * because the DMA32 kmalloc cache array is not implemented.

 * (Reason: there is no such user in kernel).

 *

 * %GFP_HIGHUSER is for userspace allocations that may be mapped to userspace,

 * do not need to be directly accessible by the kernel but that cannot

 * move once in use. An example may be a hardware allocation that maps

 * data directly into userspace but has no addressing limitations.

 *

 * %GFP_HIGHUSER_MOVABLE is for userspace allocations that the kernel does not

 * need direct access to but can use kmap() when access is required. They

 * are expected to be movable via page reclaim or page migration. Typically,

 * pages on the LRU would also be allocated with %GFP_HIGHUSER_MOVABLE.

 *

 * %GFP_TRANSHUGE and %GFP_TRANSHUGE_LIGHT are used for THP allocations. They

 * are compound allocations that will generally fail quickly if memory is not

 * available and will not wake kswapd/kcompactd on failure. The _LIGHT

 * version does not attempt reclaim/compaction at all and is by default used

 * in page fault path, while the non-light is used by khugepaged.

 */

#define GFP_ATOMIC	(__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM)

#define GFP_KERNEL	(__GFP_RECLAIM | __GFP_IO | __GFP_FS)

#define GFP_KERNEL_ACCOUNT (GFP_KERNEL | __GFP_ACCOUNT)

#define GFP_NOWAIT	(__GFP_KSWAPD_RECLAIM)

#define GFP_NOIO	(__GFP_RECLAIM)

#define GFP_NOFS	(__GFP_RECLAIM | __GFP_IO)

#define GFP_USER	(__GFP_RECLAIM | __GFP_IO | __GFP_FS | __GFP_HARDWALL)

#define GFP_DMA		__GFP_DMA

#define GFP_DMA32	__GFP_DMA32

#define GFP_HIGHUSER	(GFP_USER | __GFP_HIGHMEM)

#define GFP_HIGHUSER_MOVABLE	(GFP_HIGHUSER | __GFP_MOVABLE | \

			 __GFP_SKIP_KASAN_POISON)

#define GFP_TRANSHUGE_LIGHT	((GFP_HIGHUSER_MOVABLE | __GFP_COMP | \

			 __GFP_NOMEMALLOC | __GFP_NOWARN) & ~__GFP_RECLAIM)

#define GFP_TRANSHUGE	(GFP_TRANSHUGE_LIGHT | __GFP_DIRECT_RECLAIM)

/* Convert GFP flags to their corresponding migrate type */

#define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)

#define GFP_MOVABLE_SHIFT 3