Author: mav
Date: Fri Mar 15 18:59:04 2019
New Revision: 345200
URL: https://svnweb.freebsd.org/changeset/base/345200
Log:
MFV r336930: 9284 arc_reclaim_thread has 2 jobs
`arc_reclaim_thread()` calls `arc_adjust()` after calling
`arc_kmem_reap_now()`; `arc_adjust()` signals `arc_get_data_buf()` to
indicate that we may no longer be `arc_is_overflowing()`.
The problem is, `arc_kmem_reap_now()` can take several seconds to
complete, has no impact on `arc_is_overflowing()`, but due to how the
code is structured, can impact how long the ARC will remain in the
`arc_is_overflowing()` state.
The fix is to use seperate threads to:
1. keep `arc_size` under `arc_c`, by calling `arc_adjust()`, which
improves `arc_is_overflowing()`
2. keep enough free memory in the system, by calling
`arc_kmem_reap_now()` plus `arc_shrink()`, which improves
`arc_available_memory()`.
illumos/illumos-gate@de753e34f9c399037936e8bc547d823bba9d4b0d
Reviewed by: Matt Ahrens <mahr...@delphix.com>
Reviewed by: Serapheim Dimitropoulos <seraph...@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakha...@delphix.com>
Reviewed by: Dan Kimmel <dan.kim...@delphix.com>
Reviewed by: Paul Dagnelie <p...@delphix.com>
Reviewed by: Dan McDonald <dan...@joyent.com>
Reviewed by: Tim Kordas <tim.kor...@joyent.com>
Approved by: Garrett D'Amore <garr...@damore.org>
Author: Brad Lewis <brad.le...@delphix.com>
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zthr.h
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zthr.c
Directory Properties:
head/sys/cddl/contrib/opensolaris/ (props changed)
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Fri Mar 15
18:53:36 2019 (r345199)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Fri Mar 15
18:59:04 2019 (r345200)
@@ -281,6 +281,7 @@
#include <sys/callb.h>
#include <sys/kstat.h>
#include <sys/trim_map.h>
+#include <sys/zthr.h>
#include <zfs_fletcher.h>
#include <sys/sdt.h>
#include <sys/aggsum.h>
@@ -296,11 +297,23 @@ int arc_procfd;
#endif
#endif /* illumos */
-static kmutex_t arc_reclaim_lock;
-static kcondvar_t arc_reclaim_thread_cv;
-static boolean_t arc_reclaim_thread_exit;
-static kcondvar_t arc_reclaim_waiters_cv;
+/*
+ * This thread's job is to keep enough free memory in the system, by
+ * calling arc_kmem_reap_now() plus arc_shrink(), which improves
+ * arc_available_memory().
+ */
+static zthr_t *arc_reap_zthr;
+/*
+ * This thread's job is to keep arc_size under arc_c, by calling
+ * arc_adjust(), which improves arc_is_overflowing().
+ */
+static zthr_t *arc_adjust_zthr;
+
+static kmutex_t arc_adjust_lock;
+static kcondvar_t arc_adjust_waiters_cv;
+static boolean_t arc_adjust_needed = B_FALSE;
+
static kmutex_t arc_dnlc_evicts_lock;
static kcondvar_t arc_dnlc_evicts_cv;
static boolean_t arc_dnlc_evicts_thread_exit;
@@ -317,19 +330,23 @@ uint_t arc_reduce_dnlc_percent = 3;
int zfs_arc_evict_batch_limit = 10;
/* number of seconds before growing cache again */
-static int arc_grow_retry = 60;
+int arc_grow_retry = 60;
-/* number of milliseconds before attempting a kmem-cache-reap */
-static int arc_kmem_cache_reap_retry_ms = 0;
+/*
+ * Minimum time between calls to arc_kmem_reap_soon(). Note that this will
+ * be converted to ticks, so with the default hz=100, a setting of 15 ms
+ * will actually wait 2 ticks, or 20ms.
+ */
+int arc_kmem_cache_reap_retry_ms = 1000;
/* shift of arc_c for calculating overflow limit in arc_get_data_impl */
-int zfs_arc_overflow_shift = 8;
+int zfs_arc_overflow_shift = 8;
/* shift of arc_c for calculating both min and max arc_p */
-static int arc_p_min_shift = 4;
+int arc_p_min_shift = 4;
/* log2(fraction of arc to reclaim) */
-static int arc_shrink_shift = 7;
+int arc_shrink_shift = 7;
/*
* log2(fraction of ARC which must be free to allow growing).
@@ -355,7 +372,7 @@ static int zfs_arc_min_prescient_prefetch_ms = 6;
*/
int arc_lotsfree_percent = 10;
-static int arc_dead;
+static boolean_t arc_initialized;
extern boolean_t zfs_prefetch_disable;
/*
@@ -1052,6 +1069,7 @@ static kmutex_t arc_prune_mtx;
static taskq_t *arc_prune_taskq;
static int arc_no_grow; /* Don't try to grow cache size */
+static hrtime_t arc_growtime;
static uint64_t arc_tempreserve;
static uint64_t arc_loaned_bytes;
@@ -1819,8 +1837,8 @@ hdr_recl(void *unused)
* umem calls the reclaim func when we destroy the buf cache,
* which is after we do arc_fini().
*/
- if (!arc_dead)
- cv_signal(&arc_reclaim_thread_cv);
+ if (arc_initialized)
+ zthr_wakeup(arc_reap_zthr);
}
static void
@@ -3905,13 +3923,14 @@ arc_evict_state_impl(multilist_t *ml, int idx, arc_buf
* function should proceed in this case).
*
* If threads are left sleeping, due to not
- * using cv_broadcast, they will be woken up
- * just before arc_reclaim_thread() sleeps.
+ * using cv_broadcast here, they will be woken
+ * up via cv_broadcast in arc_adjust_cb() just
+ * before arc_adjust_zthr sleeps.
*/
- mutex_enter(&arc_reclaim_lock);
+ mutex_enter(&arc_adjust_lock);
if (!arc_is_overflowing())
- cv_signal(&arc_reclaim_waiters_cv);
- mutex_exit(&arc_reclaim_lock);
+ cv_signal(&arc_adjust_waiters_cv);
+ mutex_exit(&arc_adjust_lock);
} else {
ARCSTAT_BUMP(arcstat_mutex_miss);
}
@@ -4565,8 +4584,8 @@ arc_flush(spa_t *spa, boolean_t retry)
(void) arc_flush_state(arc_mfu_ghost, guid, ARC_BUFC_METADATA, retry);
}
-uint64_t
-arc_shrink(int64_t to_free)
+static void
+arc_reduce_target_size(int64_t to_free)
{
uint64_t asize = aggsum_value(&arc_size);
if (arc_c > arc_c_min) {
@@ -4593,9 +4612,12 @@ arc_shrink(int64_t to_free)
if (asize > arc_c) {
DTRACE_PROBE2(arc__shrink_adjust, uint64_t, asize,
uint64_t, arc_c);
- return (arc_adjust());
+ /* See comment in arc_adjust_cb_check() on why lock+flag */
+ mutex_enter(&arc_adjust_lock);
+ arc_adjust_needed = B_TRUE;
+ mutex_exit(&arc_adjust_lock);
+ zthr_wakeup(arc_adjust_zthr);
}
- return (0);
}
typedef enum free_memory_reason_t {
@@ -4765,7 +4787,7 @@ extern kmem_cache_t *range_seg_cache;
extern kmem_cache_t *abd_chunk_cache;
static __noinline void
-arc_kmem_reap_now(void)
+arc_kmem_reap_soon(void)
{
size_t i;
kmem_cache_t *prev_cache = NULL;
@@ -4788,16 +4810,6 @@ arc_kmem_reap_now(void)
#endif
#endif
- /*
- * If a kmem reap is already active, don't schedule more. We must
- * check for this because kmem_cache_reap_soon() won't actually
- * block on the cache being reaped (this is to prevent callers from
- * becoming implicitly blocked by a system-wide kmem reap -- which,
- * on a system with many, many full magazines, can take minutes).
- */
- if (kmem_cache_reap_active())
- return;
-
for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) {
if (zio_buf_cache[i] != prev_cache) {
prev_cache = zio_buf_cache[i];
@@ -4826,141 +4838,163 @@ arc_kmem_reap_now(void)
DTRACE_PROBE(arc__kmem_reap_end);
}
-/*
- * Threads can block in arc_get_data_impl() waiting for this thread to evict
- * enough data and signal them to proceed. When this happens, the threads in
- * arc_get_data_impl() are sleeping while holding the hash lock for their
- * particular arc header. Thus, we must be careful to never sleep on a
- * hash lock in this thread. This is to prevent the following deadlock:
- *
- * - Thread A sleeps on CV in arc_get_data_impl() holding hash lock "L",
- * waiting for the reclaim thread to signal it.
- *
- * - arc_reclaim_thread() tries to acquire hash lock "L" using mutex_enter,
- * fails, and goes to sleep forever.
- *
- * This possible deadlock is avoided by always acquiring a hash lock
- * using mutex_tryenter() from arc_reclaim_thread().
- */
/* ARGSUSED */
-static void
-arc_reclaim_thread(void *unused __unused)
+static boolean_t
+arc_adjust_cb_check(void *arg, zthr_t *zthr)
{
- hrtime_t growtime = 0;
- hrtime_t kmem_reap_time = 0;
- callb_cpr_t cpr;
+ /*
+ * This is necessary in order for the mdb ::arc dcmd to
+ * show up to date information. Since the ::arc command
+ * does not call the kstat's update function, without
+ * this call, the command may show stale stats for the
+ * anon, mru, mru_ghost, mfu, and mfu_ghost lists. Even
+ * with this change, the data might be up to 1 second
+ * out of date(the arc_adjust_zthr has a maximum sleep
+ * time of 1 second); but that should suffice. The
+ * arc_state_t structures can be queried directly if more
+ * accurate information is needed.
+ */
+ if (arc_ksp != NULL)
+ arc_ksp->ks_update(arc_ksp, KSTAT_READ);
- CALLB_CPR_INIT(&cpr, &arc_reclaim_lock, callb_generic_cpr, FTAG);
+ /*
+ * We have to rely on arc_get_data_impl() to tell us when to adjust,
+ * rather than checking if we are overflowing here, so that we are
+ * sure to not leave arc_get_data_impl() waiting on
+ * arc_adjust_waiters_cv. If we have become "not overflowing" since
+ * arc_get_data_impl() checked, we need to wake it up. We could
+ * broadcast the CV here, but arc_get_data_impl() may have not yet
+ * gone to sleep. We would need to use a mutex to ensure that this
+ * function doesn't broadcast until arc_get_data_impl() has gone to
+ * sleep (e.g. the arc_adjust_lock). However, the lock ordering of
+ * such a lock would necessarily be incorrect with respect to the
+ * zthr_lock, which is held before this function is called, and is
+ * held by arc_get_data_impl() when it calls zthr_wakeup().
+ */
+ return (arc_adjust_needed);
+}
- mutex_enter(&arc_reclaim_lock);
- while (!arc_reclaim_thread_exit) {
- uint64_t evicted = 0;
+/*
+ * Keep arc_size under arc_c by running arc_adjust which evicts data
+ * from the ARC. */
+/* ARGSUSED */
+static int
+arc_adjust_cb(void *arg, zthr_t *zthr)
+{
+ uint64_t evicted = 0;
+ /* Evict from cache */
+ evicted = arc_adjust();
+
+ /*
+ * If evicted is zero, we couldn't evict anything
+ * via arc_adjust(). This could be due to hash lock
+ * collisions, but more likely due to the majority of
+ * arc buffers being unevictable. Therefore, even if
+ * arc_size is above arc_c, another pass is unlikely to
+ * be helpful and could potentially cause us to enter an
+ * infinite loop. Additionally, zthr_iscancelled() is
+ * checked here so that if the arc is shutting down, the
+ * broadcast will wake any remaining arc adjust waiters.
+ */
+ mutex_enter(&arc_adjust_lock);
+ arc_adjust_needed = !zthr_iscancelled(arc_adjust_zthr) &&
+ evicted > 0 && aggsum_compare(&arc_size, arc_c) > 0;
+ if (!arc_adjust_needed) {
/*
- * This is necessary in order for the mdb ::arc dcmd to
- * show up to date information. Since the ::arc command
- * does not call the kstat's update function, without
- * this call, the command may show stale stats for the
- * anon, mru, mru_ghost, mfu, and mfu_ghost lists. Even
- * with this change, the data might be up to 1 second
- * out of date; but that should suffice. The arc_state_t
- * structures can be queried directly if more accurate
- * information is needed.
+ * We're either no longer overflowing, or we
+ * can't evict anything more, so we should wake
+ * up any waiters.
*/
- if (arc_ksp != NULL)
- arc_ksp->ks_update(arc_ksp, KSTAT_READ);
+ cv_broadcast(&arc_adjust_waiters_cv);
+ }
+ mutex_exit(&arc_adjust_lock);
- mutex_exit(&arc_reclaim_lock);
+ return (0);
+}
+/* ARGSUSED */
+static boolean_t
+arc_reap_cb_check(void *arg, zthr_t *zthr)
+{
+ int64_t free_memory = arc_available_memory();
+
+ /*
+ * If a kmem reap is already active, don't schedule more. We must
+ * check for this because kmem_cache_reap_soon() won't actually
+ * block on the cache being reaped (this is to prevent callers from
+ * becoming implicitly blocked by a system-wide kmem reap -- which,
+ * on a system with many, many full magazines, can take minutes).
+ */
+ if (!kmem_cache_reap_active() &&
+ free_memory < 0) {
+ arc_no_grow = B_TRUE;
+ arc_warm = B_TRUE;
/*
- * We call arc_adjust() before (possibly) calling
- * arc_kmem_reap_now(), so that we can wake up
- * arc_get_data_impl() sooner.
+ * Wait at least zfs_grow_retry (default 60) seconds
+ * before considering growing.
*/
- evicted = arc_adjust();
+ arc_growtime = gethrtime() + SEC2NSEC(arc_grow_retry);
+ return (B_TRUE);
+ } else if (free_memory < arc_c >> arc_no_grow_shift) {
+ arc_no_grow = B_TRUE;
+ } else if (gethrtime() >= arc_growtime) {
+ arc_no_grow = B_FALSE;
+ }
- int64_t free_memory = arc_available_memory();
- if (free_memory < 0) {
- hrtime_t curtime = gethrtime();
- arc_no_grow = B_TRUE;
- arc_warm = B_TRUE;
+ return (B_FALSE);
+}
- /*
- * Wait at least zfs_grow_retry (default 60) seconds
- * before considering growing.
- */
- growtime = curtime + SEC2NSEC(arc_grow_retry);
+/*
+ * Keep enough free memory in the system by reaping the ARC's kmem
+ * caches. To cause more slabs to be reapable, we may reduce the
+ * target size of the cache (arc_c), causing the arc_adjust_cb()
+ * to free more buffers.
+ */
+/* ARGSUSED */
+static int
+arc_reap_cb(void *arg, zthr_t *zthr)
+{
+ int64_t free_memory;
- /*
- * Wait at least arc_kmem_cache_reap_retry_ms
- * between arc_kmem_reap_now() calls. Without
- * this check it is possible to end up in a
- * situation where we spend lots of time
- * reaping caches, while we're near arc_c_min.
- */
- if (curtime >= kmem_reap_time) {
- arc_kmem_reap_now();
- kmem_reap_time = gethrtime() +
- MSEC2NSEC(arc_kmem_cache_reap_retry_ms);
- }
+ /*
+ * Kick off asynchronous kmem_reap()'s of all our caches.
+ */
+ arc_kmem_reap_soon();
- /*
- * If we are still low on memory, shrink the ARC
- * so that we have arc_shrink_min free space.
- */
- free_memory = arc_available_memory();
+ /*
+ * Wait at least arc_kmem_cache_reap_retry_ms between
+ * arc_kmem_reap_soon() calls. Without this check it is possible to
+ * end up in a situation where we spend lots of time reaping
+ * caches, while we're near arc_c_min. Waiting here also gives the
+ * subsequent free memory check a chance of finding that the
+ * asynchronous reap has already freed enough memory, and we don't
+ * need to call arc_reduce_target_size().
+ */
+ delay((hz * arc_kmem_cache_reap_retry_ms + 999) / 1000);
- int64_t to_free =
- (arc_c >> arc_shrink_shift) - free_memory;
- if (to_free > 0) {
+ /*
+ * Reduce the target size as needed to maintain the amount of free
+ * memory in the system at a fraction of the arc_size (1/128th by
+ * default). If oversubscribed (free_memory < 0) then reduce the
+ * target arc_size by the deficit amount plus the fractional
+ * amount. If free memory is positive but less then the fractional
+ * amount, reduce by what is needed to hit the fractional amount.
+ */
+ free_memory = arc_available_memory();
+
+ int64_t to_free =
+ (arc_c >> arc_shrink_shift) - free_memory;
+ if (to_free > 0) {
#ifdef _KERNEL
#ifdef illumos
- to_free = MAX(to_free, ptob(needfree));
+ to_free = MAX(to_free, ptob(needfree));
#endif
#endif
- evicted += arc_shrink(to_free);
- }
- } else if (free_memory < arc_c >> arc_no_grow_shift) {
- arc_no_grow = B_TRUE;
- } else if (gethrtime() >= growtime) {
- arc_no_grow = B_FALSE;
- }
-
- mutex_enter(&arc_reclaim_lock);
-
- /*
- * If evicted is zero, we couldn't evict anything via
- * arc_adjust(). This could be due to hash lock
- * collisions, but more likely due to the majority of
- * arc buffers being unevictable. Therefore, even if
- * arc_size is above arc_c, another pass is unlikely to
- * be helpful and could potentially cause us to enter an
- * infinite loop.
- */
- if (aggsum_compare(&arc_size, arc_c) <= 0|| evicted == 0) {
- /*
- * We're either no longer overflowing, or we
- * can't evict anything more, so we should wake
- * up any threads before we go to sleep.
- */
- cv_broadcast(&arc_reclaim_waiters_cv);
-
- /*
- * Block until signaled, or after one second (we
- * might need to perform arc_kmem_reap_now()
- * even if we aren't being signalled)
- */
- CALLB_CPR_SAFE_BEGIN(&cpr);
- (void) cv_timedwait_hires(&arc_reclaim_thread_cv,
- &arc_reclaim_lock, SEC2NSEC(1), MSEC2NSEC(1), 0);
- CALLB_CPR_SAFE_END(&cpr, &arc_reclaim_lock);
- }
+ arc_reduce_target_size(to_free);
}
- arc_reclaim_thread_exit = B_FALSE;
- cv_broadcast(&arc_reclaim_thread_cv);
- CALLB_CPR_EXIT(&cpr); /* drops arc_reclaim_lock */
- thread_exit();
+ return (0);
}
static u_int arc_dnlc_evicts_arg;
@@ -5055,8 +5089,11 @@ arc_adapt(int bytes, arc_state_t *state)
}
ASSERT((int64_t)arc_p >= 0);
+ /*
+ * Wake reap thread if we do not have any available memory
+ */
if (arc_reclaim_needed()) {
- cv_signal(&arc_reclaim_thread_cv);
+ zthr_wakeup(arc_reap_zthr);
return;
}
@@ -5164,7 +5201,7 @@ arc_get_data_impl(arc_buf_hdr_t *hdr, uint64_t size, v
* overflowing; thus we don't use a while loop here.
*/
if (arc_is_overflowing()) {
- mutex_enter(&arc_reclaim_lock);
+ mutex_enter(&arc_adjust_lock);
/*
* Now that we've acquired the lock, we may no longer be
@@ -5178,11 +5215,12 @@ arc_get_data_impl(arc_buf_hdr_t *hdr, uint64_t size, v
* shouldn't cause any harm.
*/
if (arc_is_overflowing()) {
- cv_signal(&arc_reclaim_thread_cv);
- cv_wait(&arc_reclaim_waiters_cv, &arc_reclaim_lock);
+ arc_adjust_needed = B_TRUE;
+ zthr_wakeup(arc_adjust_zthr);
+ (void) cv_wait(&arc_adjust_waiters_cv,
+ &arc_adjust_lock);
}
-
- mutex_exit(&arc_reclaim_lock);
+ mutex_exit(&arc_adjust_lock);
}
VERIFY3U(hdr->b_type, ==, type);
@@ -6898,19 +6936,28 @@ static eventhandler_tag arc_event_lowmem = NULL;
static void
arc_lowmem(void *arg __unused, int howto __unused)
{
+ int64_t free_memory, to_free;
- mutex_enter(&arc_reclaim_lock);
- DTRACE_PROBE1(arc__needfree, int64_t, ((int64_t)freemem -
zfs_arc_free_target) * PAGESIZE);
- cv_signal(&arc_reclaim_thread_cv);
+ 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);
+ mutex_enter(&arc_adjust_lock);
+ arc_adjust_needed = B_TRUE;
+ zthr_wakeup(arc_adjust_zthr);
+
/*
* 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)
- (void) cv_wait(&arc_reclaim_waiters_cv, &arc_reclaim_lock);
- mutex_exit(&arc_reclaim_lock);
+ (void) cv_wait(&arc_adjust_waiters_cv, &arc_adjust_lock);
+ mutex_exit(&arc_adjust_lock);
}
#endif
@@ -7052,12 +7099,9 @@ arc_init(void)
#else
uint64_t allmem = kmem_size();
#endif
+ mutex_init(&arc_adjust_lock, NULL, MUTEX_DEFAULT, NULL);
+ cv_init(&arc_adjust_waiters_cv, NULL, CV_DEFAULT, NULL);
-
- mutex_init(&arc_reclaim_lock, NULL, MUTEX_DEFAULT, NULL);
- cv_init(&arc_reclaim_thread_cv, NULL, CV_DEFAULT, NULL);
- cv_init(&arc_reclaim_waiters_cv, NULL, CV_DEFAULT, NULL);
-
mutex_init(&arc_dnlc_evicts_lock, NULL, MUTEX_DEFAULT, NULL);
cv_init(&arc_dnlc_evicts_cv, NULL, CV_DEFAULT, NULL);
@@ -7159,6 +7203,13 @@ arc_init(void)
zfs_arc_max = arc_c_max;
arc_state_init();
+
+ /*
+ * The arc must be "uninitialized", so that hdr_recl() (which is
+ * registered by buf_init()) will not access arc_reap_zthr before
+ * it is created.
+ */
+ ASSERT(!arc_initialized);
buf_init();
list_create(&arc_prune_list, sizeof (arc_prune_t),
@@ -7168,7 +7219,6 @@ arc_init(void)
arc_prune_taskq = taskq_create("arc_prune", max_ncpus, minclsyspri,
max_ncpus, INT_MAX, TASKQ_PREPOPULATE | TASKQ_DYNAMIC);
- arc_reclaim_thread_exit = B_FALSE;
arc_dnlc_evicts_thread_exit = FALSE;
arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED,
@@ -7180,8 +7230,10 @@ arc_init(void)
kstat_install(arc_ksp);
}
- (void) thread_create(NULL, 0, arc_reclaim_thread, NULL, 0, &p0,
- TS_RUN, minclsyspri);
+ arc_adjust_zthr = zthr_create_timer(arc_adjust_cb_check,
+ arc_adjust_cb, NULL, SEC2NSEC(1));
+ arc_reap_zthr = zthr_create_timer(arc_reap_cb_check,
+ arc_reap_cb, NULL, SEC2NSEC(1));
#ifdef _KERNEL
arc_event_lowmem = EVENTHANDLER_REGISTER(vm_lowmem, arc_lowmem, NULL,
@@ -7191,7 +7243,7 @@ arc_init(void)
(void) thread_create(NULL, 0, arc_dnlc_evicts_thread, NULL, 0, &p0,
TS_RUN, minclsyspri);
- arc_dead = B_FALSE;
+ arc_initialized = B_TRUE;
arc_warm = B_FALSE;
/*
@@ -7256,18 +7308,6 @@ arc_fini(void)
EVENTHANDLER_DEREGISTER(vm_lowmem, arc_event_lowmem);
#endif
- mutex_enter(&arc_reclaim_lock);
- arc_reclaim_thread_exit = B_TRUE;
- /*
- * The reclaim thread will set arc_reclaim_thread_exit back to
- * B_FALSE when it is finished exiting; we're waiting for that.
- */
- while (arc_reclaim_thread_exit) {
- cv_signal(&arc_reclaim_thread_cv);
- cv_wait(&arc_reclaim_thread_cv, &arc_reclaim_lock);
- }
- mutex_exit(&arc_reclaim_lock);
-
/* Use B_TRUE to ensure *all* buffers are evicted */
arc_flush(NULL, B_TRUE);
@@ -7283,7 +7323,7 @@ arc_fini(void)
}
mutex_exit(&arc_dnlc_evicts_lock);
- arc_dead = B_TRUE;
+ arc_initialized = B_FALSE;
if (arc_ksp != NULL) {
kstat_delete(arc_ksp);
@@ -7304,12 +7344,18 @@ arc_fini(void)
list_destroy(&arc_prune_list);
mutex_destroy(&arc_prune_mtx);
- mutex_destroy(&arc_reclaim_lock);
- cv_destroy(&arc_reclaim_thread_cv);
- cv_destroy(&arc_reclaim_waiters_cv);
+ (void) zthr_cancel(arc_adjust_zthr);
+ zthr_destroy(arc_adjust_zthr);
+
mutex_destroy(&arc_dnlc_evicts_lock);
cv_destroy(&arc_dnlc_evicts_cv);
+
+ (void) zthr_cancel(arc_reap_zthr);
+ zthr_destroy(arc_reap_zthr);
+
+ mutex_destroy(&arc_adjust_lock);
+ cv_destroy(&arc_adjust_waiters_cv);
arc_state_fini();
buf_fini();
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zthr.h
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zthr.h Fri Mar
15 18:53:36 2019 (r345199)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zthr.h Fri Mar
15 18:59:04 2019 (r345200)
@@ -29,6 +29,7 @@ struct zthr {
kmutex_t zthr_lock;
kcondvar_t zthr_cv;
boolean_t zthr_cancel;
+ hrtime_t zthr_wait_time;
zthr_checkfunc_t *zthr_checkfunc;
zthr_func_t *zthr_func;
@@ -38,6 +39,9 @@ struct zthr {
extern zthr_t *zthr_create(zthr_checkfunc_t checkfunc,
zthr_func_t *func, void *arg);
+extern zthr_t *zthr_create_timer(zthr_checkfunc_t *checkfunc,
+ zthr_func_t *func, void *arg, hrtime_t nano_wait);
+
extern void zthr_exit(zthr_t *t, int rc);
extern void zthr_destroy(zthr_t *t);
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zthr.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zthr.c Fri Mar 15
18:53:36 2019 (r345199)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zthr.c Fri Mar 15
18:59:04 2019 (r345200)
@@ -47,6 +47,10 @@
* 3] When the zthr is done, it changes the indicator to stopped, allowing
* a new cycle to start.
*
+ * Besides being awakened by other threads, a zthr can be configured
+ * during creation to wakeup on it's own after a specified interval
+ * [see zthr_create_timer()].
+ *
* == ZTHR creation
*
* Every zthr needs three inputs to start running:
@@ -74,6 +78,9 @@
*
* To start a zthr:
* zthr_t *zthr_pointer = zthr_create(checkfunc, func, args);
+ * or
+ * zthr_t *zthr_pointer = zthr_create_timer(checkfunc, func,
+ * args, max_sleep);
*
* After that you should be able to wakeup, cancel, and resume the
* zthr from another thread using zthr_pointer.
@@ -189,7 +196,13 @@ zthr_procedure(void *arg)
mutex_enter(&t->zthr_lock);
} else {
/* go to sleep */
- cv_wait(&t->zthr_cv, &t->zthr_lock);
+ if (t->zthr_wait_time == 0) {
+ cv_wait(&t->zthr_cv, &t->zthr_lock);
+ } else {
+ (void) cv_timedwait_hires(&t->zthr_cv,
+ &t->zthr_lock, t->zthr_wait_time,
+ MSEC2NSEC(1), 0);
+ }
}
}
mutex_exit(&t->zthr_lock);
@@ -200,6 +213,18 @@ zthr_procedure(void *arg)
zthr_t *
zthr_create(zthr_checkfunc_t *checkfunc, zthr_func_t *func, void *arg)
{
+ return (zthr_create_timer(checkfunc, func, arg, (hrtime_t)0));
+}
+
+/*
+ * Create a zthr with specified maximum sleep time. If the time
+ * in sleeping state exceeds max_sleep, a wakeup(do the check and
+ * start working if required) will be triggered.
+ */
+zthr_t *
+zthr_create_timer(zthr_checkfunc_t *checkfunc, zthr_func_t *func,
+ void *arg, hrtime_t max_sleep)
+{
zthr_t *t = kmem_zalloc(sizeof (*t), KM_SLEEP);
mutex_init(&t->zthr_lock, NULL, MUTEX_DEFAULT, NULL);
cv_init(&t->zthr_cv, NULL, CV_DEFAULT, NULL);
@@ -208,6 +233,7 @@ zthr_create(zthr_checkfunc_t *checkfunc, zthr_func_t *
t->zthr_checkfunc = checkfunc;
t->zthr_func = func;
t->zthr_arg = arg;
+ t->zthr_wait_time = max_sleep;
t->zthr_thread = thread_create(NULL, 0, zthr_procedure, t,
0, &p0, TS_RUN, minclsyspri);
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