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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
#include <sys/spa.h>
#include <sys/zio.h>
#include <sys/spa_impl.h>
#include <sys/counter.h>
#include <sys/zio_compress.h>
#include <sys/zio_checksum.h>
#include <sys/zfs_context.h>
#include <sys/arc.h>
#include <sys/zfs_refcount.h>
#include <sys/vdev.h>
#include <sys/vdev_trim.h>
#include <sys/vdev_impl.h>
#include <sys/dsl_pool.h>
#include <sys/zio_checksum.h>
#include <sys/multilist.h>
#include <sys/abd.h>
#include <sys/zil.h>
#include <sys/fm/fs/zfs.h>
#include <sys/eventhandler.h>
#include <sys/callb.h>
#include <sys/kstat.h>
#include <sys/zthr.h>
#include <zfs_fletcher.h>
#include <sys/arc_impl.h>
#include <sys/sdt.h>
#include <sys/aggsum.h>
#include <sys/vnode.h>
#include <cityhash.h>
#include <machine/vmparam.h>
#include <sys/vm.h>
#include <sys/vmmeter.h>
extern struct vfsops zfs_vfsops;
uint_t zfs_arc_free_target = 0;
static void
arc_free_target_init(void *unused __unused)
{
zfs_arc_free_target = vm_cnt.v_free_target;
}
SYSINIT(arc_free_target_init, SI_SUB_KTHREAD_PAGE, SI_ORDER_ANY,
arc_free_target_init, NULL);
/*
* We don't have a tunable for arc_free_target due to the dependency on
* pagedaemon initialisation.
*/
static int
sysctl_vfs_zfs_arc_free_target(SYSCTL_HANDLER_ARGS)
{
uint_t val;
int err;
val = zfs_arc_free_target;
err = sysctl_handle_int(oidp, &val, 0, req);
if (err != 0 || req->newptr == NULL)
return (err);
if (val < minfree)
return (EINVAL);
if (val > vm_cnt.v_page_count)
return (EINVAL);
zfs_arc_free_target = val;
return (0);
}
SYSCTL_DECL(_vfs_zfs);
/* BEGIN CSTYLED */
SYSCTL_PROC(_vfs_zfs, OID_AUTO, arc_free_target,
CTLTYPE_UINT | CTLFLAG_MPSAFE | CTLFLAG_RW, 0, sizeof (uint_t),
sysctl_vfs_zfs_arc_free_target, "IU",
"Desired number of free pages below which ARC triggers reclaim");
/* END CSTYLED */
int64_t
arc_available_memory(void)
{
int64_t lowest = INT64_MAX;
int64_t n __unused;
/*
* Cooperate with pagedaemon when it's time for it to scan
* and reclaim some pages.
*/
n = PAGESIZE * ((int64_t)freemem - zfs_arc_free_target);
if (n < lowest) {
lowest = n;
}
#if defined(__i386) || !defined(UMA_MD_SMALL_ALLOC)
/*
* If we're on an i386 platform, it's possible that we'll exhaust the
* kernel heap space before we ever run out of available physical
* memory. Most checks of the size of the heap_area compare against
* tune.t_minarmem, which is the minimum available real memory that we
* can have in the system. However, this is generally fixed at 25 pages
* which is so low that it's useless. In this comparison, we seek to
* calculate the total heap-size, and reclaim if more than 3/4ths of the
* heap is allocated. (Or, in the calculation, if less than 1/4th is
* free)
*/
n = uma_avail() - (long)(uma_limit() / 4);
if (n < lowest) {
lowest = n;
}
#endif
DTRACE_PROBE1(arc__available_memory, int64_t, lowest);
return (lowest);
}
/*
* Return a default max arc size based on the amount of physical memory.
*/
uint64_t
arc_default_max(uint64_t min, uint64_t allmem)
{
uint64_t size;
if (allmem >= 1 << 30)
size = allmem - (1 << 30);
else
size = min;
return (MAX(allmem * 5 / 8, size));
}
/*
* Helper function for arc_prune_async() it is responsible for safely
* handling the execution of a registered arc_prune_func_t.
*/
static void
arc_prune_task(void *arg)
{
int64_t nr_scan = *(int64_t *)arg;
arc_reduce_target_size(ptob(nr_scan));
free(arg, M_TEMP);
vnlru_free(nr_scan, &zfs_vfsops);
}
/*
* Notify registered consumers they must drop holds on a portion of the ARC
* buffered they reference. This provides a mechanism to ensure the ARC can
* honor the arc_meta_limit and reclaim otherwise pinned ARC buffers. This
* is analogous to dnlc_reduce_cache() but more generic.
*
* This operation is performed asynchronously so it may be safely called
* in the context of the arc_reclaim_thread(). A reference is taken here
* for each registered arc_prune_t and the arc_prune_task() is responsible
* for releasing it once the registered arc_prune_func_t has completed.
*/
void
arc_prune_async(int64_t adjust)
{
int64_t *adjustptr;
if ((adjustptr = malloc(sizeof (int64_t), M_TEMP, M_NOWAIT)) == NULL)
return;
*adjustptr = adjust;
taskq_dispatch(arc_prune_taskq, arc_prune_task, adjustptr, TQ_SLEEP);
ARCSTAT_BUMP(arcstat_prune);
}
uint64_t
arc_all_memory(void)
{
return (ptob(physmem));
}
int
arc_memory_throttle(spa_t *spa, uint64_t reserve, uint64_t txg)
{
return (0);
}
uint64_t
arc_free_memory(void)
{
return (ptob(freemem));
}
static eventhandler_tag arc_event_lowmem = NULL;
static void
arc_lowmem(void *arg __unused, int howto __unused)
{
int64_t free_memory, to_free;
arc_no_grow = B_TRUE;
arc_warm = B_TRUE;
arc_growtime = gethrtime() + SEC2NSEC(arc_grow_retry);
free_memory = arc_available_memory();
to_free = (arc_c >> arc_shrink_shift) - MIN(free_memory, 0);
DTRACE_PROBE2(arc__needfree, int64_t, free_memory, int64_t, to_free);
arc_reduce_target_size(to_free);
/*
* It is unsafe to block here in arbitrary threads, because we can come
* here from ARC itself and may hold ARC locks and thus risk a deadlock
* with ARC reclaim thread.
*/
if (curproc == pageproc)
arc_wait_for_eviction(to_free);
else
arc_wait_for_eviction(0);
}
void
arc_lowmem_init(void)
{
arc_event_lowmem = EVENTHANDLER_REGISTER(vm_lowmem, arc_lowmem, NULL,
EVENTHANDLER_PRI_FIRST);
}
void
arc_lowmem_fini(void)
{
if (arc_event_lowmem != NULL)
EVENTHANDLER_DEREGISTER(vm_lowmem, arc_event_lowmem);
}
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