From 957dc1037a87cf4e2748010b9469511b721f7067 Mon Sep 17 00:00:00 2001 From: Rob Norris Date: Sun, 17 Dec 2023 00:36:21 +1100 Subject: [PATCH] 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. Reviewed-by: Tony Hutter Reviewed-by: Brian Behlendorf Signed-off-by: Rob Norris Sponsored-by: https://github.com/sponsors/robn Closes #15681 --- config/kernel-shrink.m4 | 52 +++++++++++-- include/os/linux/spl/sys/shrinker.h | 66 +++++----------- module/Kbuild.in | 1 + module/os/linux/spl/spl-shrinker.c | 115 ++++++++++++++++++++++++++++ module/os/linux/zfs/arc_os.c | 11 ++- 5 files changed, 189 insertions(+), 56 deletions(-) create mode 100644 module/os/linux/spl/spl-shrinker.c diff --git a/config/kernel-shrink.m4 b/config/kernel-shrink.m4 index 1c5f753d41..4a529c43b5 100644 --- a/config/kernel-shrink.m4 +++ b/config/kernel-shrink.m4 @@ -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@@ AC_DEFUN([ZFS_AC_KERNEL_SRC_SHRINKER_CALLBACK], [ ]) ]) +dnl # +dnl # 6.7 API change +dnl # register_shrinker has been replaced by shrinker_register.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 + 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 @@ -165,14 +184,36 @@ 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]) + [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]) + ]) ]) ]) ]) @@ -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], [ diff --git a/include/os/linux/spl/sys/shrinker.h b/include/os/linux/spl/sys/shrinker.h index d472754be4..bca4c85069 100644 --- a/include/os/linux/spl/sys/shrinker.h +++ b/include/os/linux/spl/sys/shrinker.h @@ -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 */ diff --git a/module/Kbuild.in b/module/Kbuild.in index e34b9fab9e..fb22bfe733 100644 --- a/module/Kbuild.in +++ b/module/Kbuild.in @@ -79,6 +79,7 @@ SPL_OBJS := \ spl-kstat.o \ spl-proc.o \ spl-procfs-list.o \ + spl-shrinker.o \ spl-taskq.o \ spl-thread.o \ spl-trace.o \ diff --git a/module/os/linux/spl/spl-shrinker.c b/module/os/linux/spl/spl-shrinker.c new file mode 100644 index 0000000000..d5c8da471c --- /dev/null +++ b/module/os/linux/spl/spl-shrinker.c @@ -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 . + * 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 . + * + * Solaris Porting Layer (SPL) Shrinker Implementation. + */ + +#include +#include + +#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); diff --git a/module/os/linux/zfs/arc_os.c b/module/os/linux/zfs/arc_os.c index 55cdbba5b5..02dd80c060 100644 --- a/module/os/linux/zfs/arc_os.c +++ b/module/os/linux/zfs/arc_os.c @@ -253,8 +253,7 @@ 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) @@ -357,14 +356,18 @@ 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