From 5a902f5aaa1fbf6f7e459ec29f6d1d988ec78b0a Mon Sep 17 00:00:00 2001 From: Alexander Motin Date: Mon, 10 Jun 2019 12:52:25 -0400 Subject: [PATCH] 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 Reviewed-by: Brian Behlendorf Reviewed-by: George Melikov Signed-off-by: Alexander Motin Closes #8873 --- module/zfs/arc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/module/zfs/arc.c b/module/zfs/arc.c index c387fd88f..946ea3415 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -5480,7 +5480,7 @@ static boolean_t arc_is_overflowing(void) { /* 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); /* @@ -5492,7 +5492,7 @@ arc_is_overflowing(void) * in the ARC. In practice, that's in the tens of MB, which is low * 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 *