Fix comparison signedness in arc_is_overflowing()

When ARC size is very small, aggsum_lower_bound(&arc_size) may return
negative values, that due to unsigned comparison caused delays, waiting
for arc_adjust() to "fix" it by calling aggsum_value(&arc_size).  Use
of signed comparison there fixes the problem.

Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Closes #8873
This commit is contained in:
Alexander Motin 2019-06-10 12:52:25 -04:00 committed by Brian Behlendorf
parent 581c77e725
commit 72888812b0

View File

@ -5480,7 +5480,7 @@ static boolean_t
arc_is_overflowing(void) arc_is_overflowing(void)
{ {
/* Always allow at least one block of overflow */ /* Always allow at least one block of overflow */
uint64_t overflow = MAX(SPA_MAXBLOCKSIZE, int64_t overflow = MAX(SPA_MAXBLOCKSIZE,
arc_c >> zfs_arc_overflow_shift); arc_c >> zfs_arc_overflow_shift);
/* /*
@ -5492,7 +5492,7 @@ arc_is_overflowing(void)
* in the ARC. In practice, that's in the tens of MB, which is low * in the ARC. In practice, that's in the tens of MB, which is low
* enough to be safe. * enough to be safe.
*/ */
return (aggsum_lower_bound(&arc_size) >= arc_c + overflow); return (aggsum_lower_bound(&arc_size) >= (int64_t)arc_c + overflow);
} }
static abd_t * static abd_t *