linux/fs/xfs/kmem.h
Michal Hocko 91c63ecda7 xfs: map KM_MAYFAIL to __GFP_RETRY_MAYFAIL
KM_MAYFAIL didn't have any suitable GFP_FOO counterpart until recently
so it relied on the default page allocator behavior for the given set of
flags.  This means that small allocations actually never failed.

Now that we have __GFP_RETRY_MAYFAIL flag which works independently on
the allocation request size we can map KM_MAYFAIL to it.  The allocator
will try as hard as it can to fulfill the request but fails eventually
if the progress cannot be made.  It does so without triggering the OOM
killer which can be seen as an improvement because KM_MAYFAIL users
should be able to deal with allocation failures.

Link: http://lkml.kernel.org/r/20170623085345.11304-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 16:26:03 -07:00

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3.5 KiB
C

/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __XFS_SUPPORT_KMEM_H__
#define __XFS_SUPPORT_KMEM_H__
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
/*
* General memory allocation interfaces
*/
typedef unsigned __bitwise xfs_km_flags_t;
#define KM_SLEEP ((__force xfs_km_flags_t)0x0001u)
#define KM_NOSLEEP ((__force xfs_km_flags_t)0x0002u)
#define KM_NOFS ((__force xfs_km_flags_t)0x0004u)
#define KM_MAYFAIL ((__force xfs_km_flags_t)0x0008u)
#define KM_ZERO ((__force xfs_km_flags_t)0x0010u)
/*
* We use a special process flag to avoid recursive callbacks into
* the filesystem during transactions. We will also issue our own
* warnings, so we explicitly skip any generic ones (silly of us).
*/
static inline gfp_t
kmem_flags_convert(xfs_km_flags_t flags)
{
gfp_t lflags;
BUG_ON(flags & ~(KM_SLEEP|KM_NOSLEEP|KM_NOFS|KM_MAYFAIL|KM_ZERO));
if (flags & KM_NOSLEEP) {
lflags = GFP_ATOMIC | __GFP_NOWARN;
} else {
lflags = GFP_KERNEL | __GFP_NOWARN;
if (flags & KM_NOFS)
lflags &= ~__GFP_FS;
}
/*
* Default page/slab allocator behavior is to retry for ever
* for small allocations. We can override this behavior by using
* __GFP_RETRY_MAYFAIL which will tell the allocator to retry as long
* as it is feasible but rather fail than retry forever for all
* request sizes.
*/
if (flags & KM_MAYFAIL)
lflags |= __GFP_RETRY_MAYFAIL;
if (flags & KM_ZERO)
lflags |= __GFP_ZERO;
return lflags;
}
extern void *kmem_alloc(size_t, xfs_km_flags_t);
extern void *kmem_zalloc_large(size_t size, xfs_km_flags_t);
extern void *kmem_realloc(const void *, size_t, xfs_km_flags_t);
static inline void kmem_free(const void *ptr)
{
kvfree(ptr);
}
static inline void *
kmem_zalloc(size_t size, xfs_km_flags_t flags)
{
return kmem_alloc(size, flags | KM_ZERO);
}
/*
* Zone interfaces
*/
#define KM_ZONE_HWALIGN SLAB_HWCACHE_ALIGN
#define KM_ZONE_RECLAIM SLAB_RECLAIM_ACCOUNT
#define KM_ZONE_SPREAD SLAB_MEM_SPREAD
#define KM_ZONE_ACCOUNT SLAB_ACCOUNT
#define kmem_zone kmem_cache
#define kmem_zone_t struct kmem_cache
static inline kmem_zone_t *
kmem_zone_init(int size, char *zone_name)
{
return kmem_cache_create(zone_name, size, 0, 0, NULL);
}
static inline kmem_zone_t *
kmem_zone_init_flags(int size, char *zone_name, unsigned long flags,
void (*construct)(void *))
{
return kmem_cache_create(zone_name, size, 0, flags, construct);
}
static inline void
kmem_zone_free(kmem_zone_t *zone, void *ptr)
{
kmem_cache_free(zone, ptr);
}
static inline void
kmem_zone_destroy(kmem_zone_t *zone)
{
if (zone)
kmem_cache_destroy(zone);
}
extern void *kmem_zone_alloc(kmem_zone_t *, xfs_km_flags_t);
static inline void *
kmem_zone_zalloc(kmem_zone_t *zone, xfs_km_flags_t flags)
{
return kmem_zone_alloc(zone, flags | KM_ZERO);
}
#endif /* __XFS_SUPPORT_KMEM_H__ */