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linux 6.7 compat: rework shrinker setup for heap allocations 

6.7 changes the shrinker API such that shrinkers must be allocated
dynamically by the kernel. To accomodate this, this commit reworks
spl_register_shrinker() to do something similar against earlier kernels.

Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://github.com/sponsors/robn
(cherry picked from commit 03b84099d9)
This commit is contained in:
Rob Norris 2023-12-17 00:36:21 +11:00 committed by Tony Hutter
parent 72bf91dfdb
commit 5f465d1515
5 changed files with 189 additions and 56 deletions
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44
config/kernel-shrink.m4
View File

@ -128,6 +128,25 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_SHRINKER_CALLBACK], [
])
])
dnl #
dnl # 6.7 API change
dnl # register_shrinker has been replaced by shrinker_register.
dnl #
AC_DEFUN([ZFS_AC_KERNEL_SRC_SHRINKER_REGISTER], [
ZFS_LINUX_TEST_SRC([shrinker_register], [
#include <linux/shrinker.h>
unsigned long shrinker_cb(struct shrinker *shrink,
struct shrink_control *sc) { return 0; }
],[
struct shrinker cache_shrinker = {
.count_objects = shrinker_cb,
.scan_objects = shrinker_cb,
.seeks = DEFAULT_SEEKS,
};
shrinker_register(&cache_shrinker);
])
])
AC_DEFUN([ZFS_AC_KERNEL_SHRINKER_CALLBACK],[
dnl #
dnl # 6.0 API change
@ -165,18 +184,40 @@ AC_DEFUN([ZFS_AC_KERNEL_SHRINKER_CALLBACK],[
dnl # cs->shrink() is logically split in to
dnl # cs->count_objects() and cs->scan_objects()
dnl #
AC_MSG_CHECKING([if cs->count_objects callback exists])
AC_MSG_CHECKING(
[whether cs->count_objects callback exists])
ZFS_LINUX_TEST_RESULT(
[shrinker_cb_shrink_control_split],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_SPLIT_SHRINKER_CALLBACK, 1,
[cs->count_objects exists])
],[
AC_MSG_RESULT(no)
AC_MSG_CHECKING(
[whether shrinker_register exists])
ZFS_LINUX_TEST_RESULT([shrinker_register], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_SHRINKER_REGISTER, 1,
[shrinker_register exists])
dnl # We assume that the split shrinker
dnl # callback exists if
dnl # shrinker_register() exists,
dnl # because the latter is a much more
dnl # recent addition, and the macro
dnl # test for shrinker_register() only
dnl # works if the callback is split
AC_DEFINE(HAVE_SPLIT_SHRINKER_CALLBACK,
1, [cs->count_objects exists])
],[
AC_MSG_RESULT(no)
ZFS_LINUX_TEST_ERROR([shrinker])
])
])
])
])
])
dnl #
dnl # 2.6.39 API change,
@ -211,6 +252,7 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_SHRINKER], [
ZFS_AC_KERNEL_SRC_SHRINKER_CALLBACK
ZFS_AC_KERNEL_SRC_SHRINK_CONTROL_STRUCT
ZFS_AC_KERNEL_SRC_REGISTER_SHRINKER_VARARG
ZFS_AC_KERNEL_SRC_SHRINKER_REGISTER
])
AC_DEFUN([ZFS_AC_KERNEL_SHRINKER], [

66
include/os/linux/spl/sys/shrinker.h
View File

@ -29,12 +29,13 @@
/*
* Due to frequent changes in the shrinker API the following
* compatibility wrappers should be used. They are as follows:
* compatibility wrapper should be used.
*
* SPL_SHRINKER_DECLARE(varname, countfunc, scanfunc, seek_cost);
* shrinker = spl_register_shrinker(name, countfunc, scanfunc, seek_cost);
* spl_unregister_shrinker(shrinker);
*
* SPL_SHRINKER_DECLARE is used to declare a shrinker with the name varname,
* which is passed to spl_register_shrinker()/spl_unregister_shrinker().
* spl_register_shrinker is used to create and register a shrinker with the
* given name.
* The countfunc returns the number of free-able objects.
* The scanfunc returns the number of objects that were freed.
* The callbacks can return SHRINK_STOP if further calls can't make any more
@ -57,57 +58,28 @@
* ...scan objects in the cache and reclaim them...
* }
*
* SPL_SHRINKER_DECLARE(my_shrinker, my_count, my_scan, DEFAULT_SEEKS);
* static struct shrinker *my_shrinker;
*
* void my_init_func(void) {
* spl_register_shrinker(&my_shrinker);
* my_shrinker = spl_register_shrinker("my-shrinker",
* my_count, my_scan, DEFAULT_SEEKS);
* }
*
* void my_fini_func(void) {
* spl_unregister_shrinker(my_shrinker);
* }
*/
#ifdef HAVE_REGISTER_SHRINKER_VARARG
#define spl_register_shrinker(x) register_shrinker(x, "zfs-arc-shrinker")
#else
#define spl_register_shrinker(x) register_shrinker(x)
#endif
#define spl_unregister_shrinker(x) unregister_shrinker(x)
typedef unsigned long (*spl_shrinker_cb)
(struct shrinker *, struct shrink_control *);
/*
* Linux 3.0 to 3.11 Shrinker API Compatibility.
*/
#if defined(HAVE_SINGLE_SHRINKER_CALLBACK)
#define SPL_SHRINKER_DECLARE(varname, countfunc, scanfunc, seek_cost) \
static int \
__ ## varname ## _wrapper(struct shrinker *shrink, struct shrink_control *sc)\
{ \
if (sc->nr_to_scan != 0) { \
(void) scanfunc(shrink, sc); \
} \
return (countfunc(shrink, sc)); \
} \
\
static struct shrinker varname = { \
.shrink = __ ## varname ## _wrapper, \
.seeks = seek_cost, \
}
struct shrinker *spl_register_shrinker(const char *name,
spl_shrinker_cb countfunc, spl_shrinker_cb scanfunc, int seek_cost);
void spl_unregister_shrinker(struct shrinker *);
#ifndef SHRINK_STOP
/* 3.0-3.11 compatibility */
#define SHRINK_STOP (-1)
/*
* Linux 3.12 and later Shrinker API Compatibility.
*/
#elif defined(HAVE_SPLIT_SHRINKER_CALLBACK)
#define SPL_SHRINKER_DECLARE(varname, countfunc, scanfunc, seek_cost) \
static struct shrinker varname = { \
.count_objects = countfunc, \
.scan_objects = scanfunc, \
.seeks = seek_cost, \
}
#else
/*
* Linux 2.x to 2.6.22, or a newer shrinker API has been introduced.
*/
#error "Unknown shrinker callback"
#endif
#endif /* SPL_SHRINKER_H */

1
module/os/linux/spl/Makefile.in
View File

@ -8,6 +8,7 @@ $(MODULE)-objs += ../os/linux/spl/spl-kmem-cache.o
$(MODULE)-objs += ../os/linux/spl/spl-kstat.o
$(MODULE)-objs += ../os/linux/spl/spl-proc.o
$(MODULE)-objs += ../os/linux/spl/spl-procfs-list.o
$(MODULE)-objs += ../os/linux/spl/spl-shrinker.o
$(MODULE)-objs += ../os/linux/spl/spl-taskq.o
$(MODULE)-objs += ../os/linux/spl/spl-thread.o
$(MODULE)-objs += ../os/linux/spl/spl-trace.o

115
module/os/linux/spl/spl-shrinker.c Normal file
View File

@ -0,0 +1,115 @@
/*
* 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.
*
* 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/>.
*
* Solaris Porting Layer (SPL) Shrinker Implementation.
*/
#include <sys/kmem.h>
#include <sys/shrinker.h>
#ifdef HAVE_SINGLE_SHRINKER_CALLBACK
/* 3.0-3.11: single shrink() callback, which we wrap to carry both functions */
struct spl_shrinker_wrap {
struct shrinker shrinker;
spl_shrinker_cb countfunc;
spl_shrinker_cb scanfunc;
};
static int
spl_shrinker_single_cb(struct shrinker *shrinker, struct shrink_control *sc)
{
struct spl_shrinker_wrap *sw = (struct spl_shrinker_wrap *)shrinker;
if (sc->nr_to_scan != 0)
(void) sw->scanfunc(&sw->shrinker, sc);
return (sw->countfunc(&sw->shrinker, sc));
}
#endif
struct shrinker *
spl_register_shrinker(const char *name, spl_shrinker_cb countfunc,
spl_shrinker_cb scanfunc, int seek_cost)
{
struct shrinker *shrinker;
/* allocate shrinker */
#if defined(HAVE_SHRINKER_REGISTER)
/* 6.7: kernel will allocate the shrinker for us */
shrinker = shrinker_alloc(0, name);
#elif defined(HAVE_SPLIT_SHRINKER_CALLBACK)
/* 3.12-6.6: we allocate the shrinker */
shrinker = kmem_zalloc(sizeof (struct shrinker), KM_SLEEP);
#elif defined(HAVE_SINGLE_SHRINKER_CALLBACK)
/* 3.0-3.11: allocate a wrapper */
struct spl_shrinker_wrap *sw =
kmem_zalloc(sizeof (struct spl_shrinker_wrap), KM_SLEEP);
shrinker = &sw->shrinker;
#else
/* 2.x-2.6.22, or a newer shrinker API has been introduced. */
#error "Unknown shrinker API"
#endif
if (shrinker == NULL)
return (NULL);
/* set callbacks */
#ifdef HAVE_SINGLE_SHRINKER_CALLBACK
sw->countfunc = countfunc;
sw->scanfunc = scanfunc;
shrinker->shrink = spl_shrinker_single_cb;
#else
shrinker->count_objects = countfunc;
shrinker->scan_objects = scanfunc;
#endif
/* set params */
shrinker->seeks = seek_cost;
/* register with kernel */
#if defined(HAVE_SHRINKER_REGISTER)
shrinker_register(shrinker);
#elif defined(HAVE_REGISTER_SHRINKER_VARARG)
register_shrinker(shrinker, name);
#else
register_shrinker(shrinker);
#endif
return (shrinker);
}
EXPORT_SYMBOL(spl_register_shrinker);
void
spl_unregister_shrinker(struct shrinker *shrinker)
{
#if defined(HAVE_SHRINKER_REGISTER)
shrinker_free(shrinker);
#elif defined(HAVE_SPLIT_SHRINKER_CALLBACK)
unregister_shrinker(shrinker);
kmem_free(shrinker, sizeof (struct shrinker));
#elif defined(HAVE_SINGLE_SHRINKER_CALLBACK)
unregister_shrinker(shrinker);
kmem_free(shrinker, sizeof (struct spl_shrinker_wrap));
#else
#error "Unknown shrinker API"
#endif
}
EXPORT_SYMBOL(spl_unregister_shrinker);

11
module/os/linux/zfs/arc_os.c
View File

@ -247,8 +247,7 @@ arc_shrinker_scan(struct shrinker *shrink, struct shrink_control *sc)
return (sc->nr_to_scan);
}
SPL_SHRINKER_DECLARE(arc_shrinker,
arc_shrinker_count, arc_shrinker_scan, DEFAULT_SEEKS);
static struct shrinker *arc_shrinker = NULL;
int
arc_memory_throttle(spa_t *spa, uint64_t reserve, uint64_t txg)
@ -351,14 +350,18 @@ arc_lowmem_init(void)
* reclaim from the arc. This is done to prevent kswapd from
* swapping out pages when it is preferable to shrink the arc.
*/
spl_register_shrinker(&arc_shrinker);
arc_shrinker = spl_register_shrinker("zfs-arc-shrinker",
arc_shrinker_count, arc_shrinker_scan, DEFAULT_SEEKS);
VERIFY(arc_shrinker);
arc_set_sys_free(allmem);
}
void
arc_lowmem_fini(void)
{
spl_unregister_shrinker(&arc_shrinker);
spl_unregister_shrinker(arc_shrinker);
arc_shrinker = NULL;
}
int