mirror_zfs/include/linux/mm_compat.h
Richard Yao c3d9c0df3e Linux 3.12 compat: New shrinker API
torvalds/linux@24f7c6 introduced a new shrinker API while
torvalds/linux@a0b021 dropped support for the old shrinker API.
This patch adds support for the new shrinker API by wrapping
the old one with the new one.

This change also reorganizes the autotools checks on the shrinker
API such that the configure script will fail early if an unknown
API is encountered in the future.

Support for the set_shrinker() API which was used by Linux 2.6.22
and older has been dropped.  As a general rule compatibility is
only maintained back to Linux 2.6.26.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes zfsonlinux/zfs#1732
Closes zfsonlinux/zfs#1822
Closes #293
Closes #307
2013-11-06 13:23:40 -08:00

315 lines
12 KiB
C

/*****************************************************************************\
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://zfsonlinux.org/>.
*
* The SPL 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; either version 2 of the License, or (at your
* option) any later version.
*
* The SPL is distributed in the hope that it will 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 the SPL. If not, see <http://www.gnu.org/licenses/>.
\*****************************************************************************/
#ifndef _SPL_MM_COMPAT_H
#define _SPL_MM_COMPAT_H
#include <linux/mm.h>
#include <linux/fs.h>
/*
* Linux 2.6.31 API Change.
* Individual pages_{min,low,high} moved in to watermark array.
*/
#ifndef min_wmark_pages
#define min_wmark_pages(z) (z->pages_min)
#endif
#ifndef low_wmark_pages
#define low_wmark_pages(z) (z->pages_low)
#endif
#ifndef high_wmark_pages
#define high_wmark_pages(z) (z->pages_high)
#endif
#if !defined(HAVE_SHRINK_CONTROL_STRUCT)
struct shrink_control {
gfp_t gfp_mask;
unsigned long nr_to_scan;
};
#endif /* HAVE_SHRINK_CONTROL_STRUCT */
/*
* 2.6.xx API compat,
* There currently exists no exposed API to partially shrink the dcache.
* The expected mechanism to shrink the cache is a registered shrinker
* which is called during memory pressure.
*/
#ifndef HAVE_SHRINK_DCACHE_MEMORY
# if defined(HAVE_SHRINK_CONTROL_STRUCT)
typedef int (*shrink_dcache_memory_t)(struct shrinker *,
struct shrink_control *);
extern shrink_dcache_memory_t shrink_dcache_memory_fn;
# define shrink_dcache_memory(nr, gfp) \
({ \
struct shrink_control sc = { .nr_to_scan = nr, .gfp_mask = gfp }; \
int __ret__ = 0; \
\
if (shrink_dcache_memory_fn) \
__ret__ = shrink_dcache_memory_fn(NULL, &sc); \
\
__ret__; \
})
# elif defined(HAVE_3ARGS_SHRINKER_CALLBACK)
typedef int (*shrink_dcache_memory_t)(struct shrinker *, int, gfp_t);
extern shrink_dcache_memory_t shrink_dcache_memory_fn;
# define shrink_dcache_memory(nr, gfp) \
({ \
int __ret__ = 0; \
\
if (shrink_dcache_memory_fn) \
__ret__ = shrink_dcache_memory_fn(NULL, nr, gfp); \
\
__ret__; \
})
# else
typedef int (*shrink_dcache_memory_t)(int, gfp_t);
extern shrink_dcache_memory_t shrink_dcache_memory_fn;
# define shrink_dcache_memory(nr, gfp) \
({ \
int __ret__ = 0; \
\
if (shrink_dcache_memory_fn) \
__ret__ = shrink_dcache_memory_fn(nr, gfp); \
\
__ret__; \
})
# endif /* HAVE_3ARGS_SHRINKER_CALLBACK */
#endif /* HAVE_SHRINK_DCACHE_MEMORY */
/*
* 2.6.xx API compat,
* There currently exists no exposed API to partially shrink the icache.
* The expected mechanism to shrink the cache is a registered shrinker
* which is called during memory pressure.
*/
#ifndef HAVE_SHRINK_ICACHE_MEMORY
# if defined(HAVE_SHRINK_CONTROL_STRUCT)
typedef int (*shrink_icache_memory_t)(struct shrinker *,
struct shrink_control *);
extern shrink_icache_memory_t shrink_icache_memory_fn;
# define shrink_icache_memory(nr, gfp) \
({ \
struct shrink_control sc = { .nr_to_scan = nr, .gfp_mask = gfp }; \
int __ret__ = 0; \
\
if (shrink_icache_memory_fn) \
__ret__ = shrink_icache_memory_fn(NULL, &sc); \
\
__ret__; \
})
# elif defined(HAVE_3ARGS_SHRINKER_CALLBACK)
typedef int (*shrink_icache_memory_t)(struct shrinker *, int, gfp_t);
extern shrink_icache_memory_t shrink_icache_memory_fn;
# define shrink_icache_memory(nr, gfp) \
({ \
int __ret__ = 0; \
\
if (shrink_icache_memory_fn) \
__ret__ = shrink_icache_memory_fn(NULL, nr, gfp); \
\
__ret__; \
})
# else
typedef int (*shrink_icache_memory_t)(int, gfp_t);
extern shrink_icache_memory_t shrink_icache_memory_fn;
# define shrink_icache_memory(nr, gfp) \
({ \
int __ret__ = 0; \
\
if (shrink_icache_memory_fn) \
__ret__ = shrink_icache_memory_fn(nr, gfp); \
\
__ret__; \
})
# endif /* HAVE_3ARGS_SHRINKER_CALLBACK */
#endif /* HAVE_SHRINK_ICACHE_MEMORY */
/*
* Due to frequent changes in the shrinker API the following
* compatibility wrappers should be used. They are as follows:
*
* SPL_SHRINKER_DECLARE is used to declare the shrinker which is
* passed to spl_register_shrinker()/spl_unregister_shrinker(). Use
* shrinker_name to set the shrinker variable name, shrinker_callback
* to set the callback function, and seek_cost to define the cost of
* reclaiming an object.
*
* SPL_SHRINKER_DECLARE(shrinker_name, shrinker_callback, seek_cost);
*
* SPL_SHRINKER_CALLBACK_FWD_DECLARE is used when a forward declaration
* of the shrinker callback function is required. Only the callback
* function needs to be passed.
*
* SPL_SHRINKER_CALLBACK_FWD_DECLARE(shrinker_callback);
*
* SPL_SHRINKER_CALLBACK_WRAPPER is used to declare the callback function
* which is registered with the shrinker. This function will call your
* custom shrinker which must use the following prototype. Notice the
* leading __'s, these must be appended to the callback_function name.
*
* int __shrinker_callback(struct shrinker *, struct shrink_control *)
* SPL_SHRINKER_CALLBACK_WRAPPER(shrinker_callback);a
*
*
* Example:
*
* SPL_SHRINKER_CALLBACK_FWD_DECLARE(my_shrinker_fn);
* SPL_SHRINKER_DECLARE(my_shrinker, my_shrinker_fn, 1);
*
* static int
* __my_shrinker_fn(struct shrinker *shrink, struct shrink_control *sc)
* {
* if (sc->nr_to_scan) {
* ...scan objects in the cache and reclaim them...
* }
*
* ...calculate number of objects in the cache...
*
* return (number of objects in the cache);
* }
* SPL_SHRINKER_CALLBACK_WRAPPER(my_shrinker_fn);
*/
#define spl_register_shrinker(x) register_shrinker(x)
#define spl_unregister_shrinker(x) unregister_shrinker(x)
/*
* Linux 2.6.23 - 2.6.34 Shrinker API Compatibility.
*/
#if defined(HAVE_2ARGS_OLD_SHRINKER_CALLBACK)
#define SPL_SHRINKER_DECLARE(s, x, y) \
static struct shrinker s = { \
.shrink = x, \
.seeks = y \
}
#define SPL_SHRINKER_CALLBACK_FWD_DECLARE(fn) \
static int fn(int nr_to_scan, unsigned int gfp_mask)
#define SPL_SHRINKER_CALLBACK_WRAPPER(fn) \
static int \
fn(int nr_to_scan, unsigned int gfp_mask) \
{ \
struct shrink_control sc; \
\
sc.nr_to_scan = nr_to_scan; \
sc.gfp_mask = gfp_mask; \
\
return (__ ## fn(NULL, &sc)); \
}
/*
* Linux 2.6.35 to 2.6.39 Shrinker API Compatibility.
*/
#elif defined(HAVE_3ARGS_SHRINKER_CALLBACK)
#define SPL_SHRINKER_DECLARE(s, x, y) \
static struct shrinker s = { \
.shrink = x, \
.seeks = y \
}
#define SPL_SHRINKER_CALLBACK_FWD_DECLARE(fn) \
static int fn(struct shrinker *, int, unsigned int)
#define SPL_SHRINKER_CALLBACK_WRAPPER(fn) \
static int \
fn(struct shrinker *shrink, int nr_to_scan, unsigned int gfp_mask) \
{ \
struct shrink_control sc; \
\
sc.nr_to_scan = nr_to_scan; \
sc.gfp_mask = gfp_mask; \
\
return (__ ## fn(shrink, &sc)); \
}
/*
* Linux 3.0 to 3.11 Shrinker API Compatibility.
*/
#elif defined(HAVE_2ARGS_NEW_SHRINKER_CALLBACK)
#define SPL_SHRINKER_DECLARE(s, x, y) \
static struct shrinker s = { \
.shrink = x, \
.seeks = y \
}
#define SPL_SHRINKER_CALLBACK_FWD_DECLARE(fn) \
static int fn(struct shrinker *, struct shrink_control *)
#define SPL_SHRINKER_CALLBACK_WRAPPER(fn) \
static int \
fn(struct shrinker *shrink, struct shrink_control *sc) \
{ \
return (__ ## fn(shrink, sc)); \
}
/*
* Linux 3.12 and later Shrinker API Compatibility.
*/
#elif defined(HAVE_SPLIT_SHRINKER_CALLBACK)
#define SPL_SHRINKER_DECLARE(s, x, y) \
static struct shrinker s = { \
.count_objects = x ## _count_objects, \
.scan_objects = x ## _scan_objects, \
.seeks = y \
}
#define SPL_SHRINKER_CALLBACK_FWD_DECLARE(fn) \
static unsigned long fn ## _count_objects(struct shrinker *, \
struct shrink_control *); \
static unsigned long fn ## _scan_objects(struct shrinker *, \
struct shrink_control *)
#define SPL_SHRINKER_CALLBACK_WRAPPER(fn) \
static unsigned long \
fn ## _count_objects(struct shrinker *shrink, struct shrink_control *sc)\
{ \
int __ret__; \
\
sc->nr_to_scan = 0; \
__ret__ = __ ## fn(NULL, sc); \
\
/* Errors may not be returned and must be converted to zeros */ \
return ((__ret__ < 0) ? 0 : __ret__); \
} \
\
static unsigned long \
fn ## _scan_objects(struct shrinker *shrink, struct shrink_control *sc) \
{ \
int __ret__; \
\
__ret__ = __ ## fn(NULL, sc); \
return ((__ret__ < 0) ? SHRINK_STOP : __ret__); \
}
#else
/*
* Linux 2.x to 2.6.22, or a newer shrinker API has been introduced.
*/
#error "Unknown shrinker callback"
#endif
#endif /* SPL_MM_COMPAT_H */