linuxkpi: Add shrinker support
A driver can register a shrinker that will be called when the kernel wants to free some memory. Add support for that in linuxkpi and call the registered shrinkers when the lowmem event is triggered. Reviewed by: bz Differential Revision: https://reviews.freebsd.org/D27728
This commit is contained in:
Emmanuel Vadot
parent
105a37cac7
commit
2c95fb753f
56
sys/compat/linuxkpi/common/include/linux/shrinker.h
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56
sys/compat/linuxkpi/common/include/linux/shrinker.h
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/*-
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* Copyright (c) 2020 Emmanuel Vadot <manu@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef __LINUX_SHRINKER_H__
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#define __LINUX_SHRINKER_H__
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#include <sys/queue.h>
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struct shrink_control {
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unsigned long nr_to_scan;
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unsigned long nr_scanned;
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};
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struct shrinker {
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unsigned long (*count_objects)(struct shrinker *, struct shrink_control *);
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unsigned long (*scan_objects)(struct shrinker *, struct shrink_control *);
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int seeks;
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long batch;
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TAILQ_ENTRY(shrinker) next;
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};
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#define SHRINK_STOP (~0UL)
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#define DEFAULT_SEEKS 2
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int linuxkpi_register_shrinker(struct shrinker *s);
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void linuxkpi_unregister_shrinker(struct shrinker *s);
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#define register_shrinker(s) linuxkpi_register_shrinker(s)
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#define unregister_shrinker(s) linuxkpi_unregister_shrinker(s)
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#endif /* __LINUX_SHRINKER_H__ */
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125
sys/compat/linuxkpi/common/src/linux_shrinker.c
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125
sys/compat/linuxkpi/common/src/linux_shrinker.c
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@ -0,0 +1,125 @@
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/*-
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* Copyright (c) 2020 Emmanuel Vadot <manu@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/queue.h>
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#include <sys/eventhandler.h>
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#include <sys/mutex.h>
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#include <linux/shrinker.h>
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TAILQ_HEAD(, shrinker) lkpi_shrinkers = TAILQ_HEAD_INITIALIZER(lkpi_shrinkers);
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static struct mtx mtx_shrinker;
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int
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linuxkpi_register_shrinker(struct shrinker *s)
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{
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KASSERT(s != NULL, ("NULL shrinker"));
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KASSERT(s->count_objects != NULL, ("NULL shrinker"));
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KASSERT(s->scan_objects != NULL, ("NULL shrinker"));
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mtx_lock(&mtx_shrinker);
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TAILQ_INSERT_TAIL(&lkpi_shrinkers, s, next);
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mtx_unlock(&mtx_shrinker);
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return (0);
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}
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void
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linuxkpi_unregister_shrinker(struct shrinker *s)
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{
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mtx_lock(&mtx_shrinker);
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TAILQ_REMOVE(&lkpi_shrinkers, s, next);
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mtx_unlock(&mtx_shrinker);
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}
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#define SHRINKER_BATCH 512
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static void
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shrinker_shrink(struct shrinker *s)
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{
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struct shrink_control sc;
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unsigned long can_free;
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unsigned long batch;
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unsigned long freeed = 0;
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unsigned long ret;
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can_free = s->count_objects(s, &sc);
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if (can_free <= 0)
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return;
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batch = s->batch ? s->batch : SHRINKER_BATCH;
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while (freeed <= can_free) {
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sc.nr_to_scan = batch;
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ret = s->scan_objects(s, &sc);
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if (ret == SHRINK_STOP)
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break;
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freeed += ret;
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}
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}
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static void
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linuxkpi_vm_lowmem(void *arg __unused)
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{
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struct shrinker *s;
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mtx_lock(&mtx_shrinker);
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TAILQ_FOREACH(s, &lkpi_shrinkers, next) {
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shrinker_shrink(s);
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}
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mtx_unlock(&mtx_shrinker);
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}
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static eventhandler_tag lowmem_tag;
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static void
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linuxkpi_sysinit_shrinker(void *arg __unused)
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{
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mtx_init(&mtx_shrinker, "lkpi-shrinker", NULL, MTX_DEF);
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lowmem_tag = EVENTHANDLER_REGISTER(vm_lowmem, linuxkpi_vm_lowmem,
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NULL, EVENTHANDLER_PRI_FIRST);
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}
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static void
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linuxkpi_sysuninit_shrinker(void *arg __unused)
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{
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mtx_destroy(&mtx_shrinker);
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EVENTHANDLER_DEREGISTER(vm_lowmem, lowmem_tag);
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}
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SYSINIT(linuxkpi_shrinker, SI_SUB_DRIVERS, SI_ORDER_ANY,
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linuxkpi_sysinit_shrinker, NULL);
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SYSUNINIT(linuxkpi_shrinker, SI_SUB_DRIVERS, SI_ORDER_ANY,
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linuxkpi_sysuninit_shrinker, NULL);
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@ -4576,6 +4576,8 @@ compat/linuxkpi/common/src/linux_schedule.c optional compat_linuxkpi \
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compile-with "${LINUXKPI_C}"
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compat/linuxkpi/common/src/linux_shmemfs.c optional compat_linuxkpi \
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compile-with "${LINUXKPI_C}"
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compat/linuxkpi/common/src/linux_shrinker.c optional compat_linuxkpi \
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compile-with "${LINUXKPI_C}"
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compat/linuxkpi/common/src/linux_slab.c optional compat_linuxkpi \
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compile-with "${LINUXKPI_C}"
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compat/linuxkpi/common/src/linux_usb.c optional compat_linuxkpi usb \
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@ -17,6 +17,7 @@ SRCS= linux_compat.c \
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linux_seq_file.c \
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linux_schedule.c \
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linux_shmemfs.c \
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linux_shrinker.c \
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linux_slab.c \
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linux_tasklet.c \
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linux_usb.c \
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