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remove the poor emulation of the IllumOS needfree global variable to prevent

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the ARC reclaim thread running longer than needed.

Update the arc::needfree dtrace probe triggered in arc_lowmem() to also report
the value we may want to free.

Submitted by:	Nikita Kozlov <nikita.kozlov at blade-group.com>
Reviewed by:	avg
Approved by:	avg
MFC after:	3 weeks
Sponsored by:	blade
Differential Revision:	https://reviews.freebsd.org/D12163
This commit is contained in:
Baptiste Daroussin 2017-11-15 12:48:36 +00:00
parent 58c8430a32
commit c07d14deb5
1 changed files with 1 additions and 19 deletions
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20
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
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@ -4199,8 +4199,6 @@ arc_shrink(int64_t to_free)
}
}
static long needfree = 0;
typedef enum free_memory_reason_t {
FMR_UNKNOWN,
FMR_NEEDFREE,
@ -4238,14 +4236,6 @@ arc_available_memory(void)
free_memory_reason_t r = FMR_UNKNOWN;
#ifdef _KERNEL
if (needfree > 0) {
n = PAGESIZE * (-needfree);
if (n < lowest) {
lowest = n;
r = FMR_NEEDFREE;
}
}
/*
* Cooperate with pagedaemon when it's time for it to scan
* and reclaim some pages.
@ -4510,9 +4500,6 @@ arc_reclaim_thread(void *dummy __unused)
int64_t to_free =
(arc_c >> arc_shrink_shift) - free_memory;
if (to_free > 0) {
#ifdef _KERNEL
to_free = MAX(to_free, ptob(needfree));
#endif
arc_shrink(to_free);
}
} else if (free_memory < arc_c >> arc_no_grow_shift) {
@ -4533,9 +4520,6 @@ arc_reclaim_thread(void *dummy __unused)
* infinite loop.
*/
if (arc_size <= arc_c || evicted == 0) {
#ifdef _KERNEL
needfree = 0;
#endif
/*
* We're either no longer overflowing, or we
* can't evict anything more, so we should wake
@ -6310,9 +6294,7 @@ arc_lowmem(void *arg __unused, int howto __unused)
{
mutex_enter(&arc_reclaim_lock);
/* XXX: Memory deficit should be passed as argument. */
needfree = btoc(arc_c >> arc_shrink_shift);
DTRACE_PROBE(arc__needfree);
DTRACE_PROBE1(arc__needfree, int64_t, ((int64_t)freemem - zfs_arc_free_target) * PAGESIZE);
cv_signal(&arc_reclaim_thread_cv);
/*