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/*****************************************************************************\
* Copyright (C) 2011 Lawrence Livermore National Security, LLC.
* 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/>.
*****************************************************************************
* Solaris Porting LAyer Tests (SPLAT) Kernel Compatibility Tests.
\*****************************************************************************/
#include <sys/kmem.h>
#include <linux/mm_compat.h>
#include "splat-internal.h"
#define SPLAT_LINUX_NAME "linux"
#define SPLAT_LINUX_DESC "Kernel Compatibility Tests"
#define SPLAT_LINUX_TEST1_ID 0x1001
#define SPLAT_LINUX_TEST1_NAME "shrinker"
#define SPLAT_LINUX_TEST1_DESC "Shrinker test"
/*
* Wait queue used to eliminate race between dropping of slab
* and execution of the shrinker callback
*/
DECLARE_WAIT_QUEUE_HEAD(shrinker_wait);
SPL_SHRINKER_CALLBACK_FWD_DECLARE(splat_linux_shrinker_fn);
SPL_SHRINKER_DECLARE(splat_linux_shrinker, splat_linux_shrinker_fn, 1);
static unsigned long splat_linux_shrinker_size = 0;
static struct file *splat_linux_shrinker_file = NULL;
static spl_shrinker_t
__splat_linux_shrinker_fn(struct shrinker *shrink, struct shrink_control *sc)
{
static int failsafe = 0;
static unsigned long last_splat_linux_shrinker_size = 0;
unsigned long size;
spl_shrinker_t count;
/*
* shrinker_size can only decrease or stay the same between callbacks
* in the same run, so Reset failsafe whenever shrinker increases
* as this indicates a new run.
*/
if (last_splat_linux_shrinker_size < splat_linux_shrinker_size)
failsafe = 0;
last_splat_linux_shrinker_size = splat_linux_shrinker_size;
if (sc->nr_to_scan) {
size = MIN(sc->nr_to_scan, splat_linux_shrinker_size);
splat_linux_shrinker_size -= size;
splat_vprint(splat_linux_shrinker_file, SPLAT_LINUX_TEST1_NAME,
"Reclaimed %lu objects, size now %lu\n",
size, splat_linux_shrinker_size);
#ifdef HAVE_SPLIT_SHRINKER_CALLBACK
count = size;
#else
count = splat_linux_shrinker_size;
#endif /* HAVE_SPLIT_SHRINKER_CALLBACK */
} else {
count = splat_linux_shrinker_size;
splat_vprint(splat_linux_shrinker_file, SPLAT_LINUX_TEST1_NAME,
"Cache size is %lu\n", splat_linux_shrinker_size);
}
/* Far more calls than expected abort drop_slab as a failsafe */
if (failsafe > 100) {
splat_vprint(splat_linux_shrinker_file, SPLAT_LINUX_TEST1_NAME,
"Far more calls than expected (%d), size now %lu\n",
failsafe, splat_linux_shrinker_size);
return (SHRINK_STOP);
} else {
/*
* We only increment failsafe if it doesn't trigger. This
* makes any failsafe failure persistent until the next test.
*/
failsafe++;
}
/* Shrinker has run, so signal back to test. */
wake_up(&shrinker_wait);
return (count);
}
SPL_SHRINKER_CALLBACK_WRAPPER(splat_linux_shrinker_fn);
#define DROP_SLAB_CMD \
"exec 0</dev/null " \
" 1>/proc/sys/vm/drop_caches " \
" 2>/dev/null; " \
"echo 2"
static int
splat_linux_drop_slab(struct file *file)
{
char *argv[] = { "/bin/sh",
"-c",
DROP_SLAB_CMD,
NULL };
char *envp[] = { "HOME=/",
"TERM=linux",
"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
NULL };
int rc;
rc = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
if (rc)
splat_vprint(file, SPLAT_LINUX_TEST1_NAME,
"Failed user helper '%s %s %s', rc = %d\n",
argv[0], argv[1], argv[2], rc);
return rc;
}
/*
* Verify correct shrinker functionality by registering a shrinker
* with the required compatibility macros. We then use a simulated
* cache and force the systems caches to be dropped. The shrinker
* should be repeatedly called until it reports that the cache is
* empty. It is then cleanly unregistered and correct behavior is
* verified. There are now four slightly different supported shrinker
* API and this test ensures the compatibility code is correct.
*/
static int
splat_linux_test1(struct file *file, void *arg)
{
int rc = -EINVAL;
/*
* Globals used by the shrinker, it is not safe to run this
* test concurrently this is a safe assumption for SPLAT tests.
* Regardless we do some minimal checking a bail if concurrent
* use is detected.
*/
if (splat_linux_shrinker_size || splat_linux_shrinker_file) {
splat_vprint(file, SPLAT_LINUX_TEST1_NAME,
"Failed due to concurrent shrinker test, rc = %d\n", rc);
return (rc);
}
splat_linux_shrinker_size = 1024;
splat_linux_shrinker_file = file;
spl_register_shrinker(&splat_linux_shrinker);
rc = splat_linux_drop_slab(file);
if (rc)
goto out;
/*
* By the time we get here, it is possible that the shrinker has not
* yet run. splat_linux_drop_slab sends a signal for it to run, but
* there is no guarantee of when it will actually run. We wait for it
* to run here, terminating when either the shrinker size is now 0 or
* we timeout after 1 second, which should be an eternity (error).
*/
rc = wait_event_timeout(shrinker_wait, !splat_linux_shrinker_size, HZ);
if (!rc) {
splat_vprint(file, SPLAT_LINUX_TEST1_NAME,
"Failed cache shrinking timed out, size now %lu",
splat_linux_shrinker_size);
rc = -ETIMEDOUT;
} else {
rc = 0;
}
if (!rc && splat_linux_shrinker_size != 0) {
splat_vprint(file, SPLAT_LINUX_TEST1_NAME,
"Failed cache was not shrunk to 0, size now %lu",
splat_linux_shrinker_size);
rc = -EDOM;
}
out:
spl_unregister_shrinker(&splat_linux_shrinker);
splat_linux_shrinker_size = 0;
splat_linux_shrinker_file = NULL;
return rc;
}
splat_subsystem_t *
splat_linux_init(void)
{
splat_subsystem_t *sub;
sub = kmalloc(sizeof(*sub), GFP_KERNEL);
if (sub == NULL)
return NULL;
memset(sub, 0, sizeof(*sub));
strncpy(sub->desc.name, SPLAT_LINUX_NAME, SPLAT_NAME_SIZE);
strncpy(sub->desc.desc, SPLAT_LINUX_DESC, SPLAT_DESC_SIZE);
INIT_LIST_HEAD(&sub->subsystem_list);
INIT_LIST_HEAD(&sub->test_list);
spin_lock_init(&sub->test_lock);
sub->desc.id = SPLAT_SUBSYSTEM_LINUX;
SPLAT_TEST_INIT(sub, SPLAT_LINUX_TEST1_NAME, SPLAT_LINUX_TEST1_DESC,
SPLAT_LINUX_TEST1_ID, splat_linux_test1);
return sub;
}
void
splat_linux_fini(splat_subsystem_t *sub)
{
ASSERT(sub);
SPLAT_TEST_FINI(sub, SPLAT_LINUX_TEST1_ID);
kfree(sub);
}
int
splat_linux_id(void) {
return SPLAT_SUBSYSTEM_LINUX;
}
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