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| author | Mark Johnston <markj@FreeBSD.org> | 2018-09-18 17:51:45 +0000 |
|---|---|---|
| committer | Mark Johnston <markj@FreeBSD.org> | 2018-09-18 17:51:45 +0000 |
| commit | 26fe2217bfbd6aa6ec67f5c57a2e7344bcf2fdff (patch) | |
| tree | 091669dc29821f2709619bf4ee62b4f36c23ab75 | |
| parent | dc39aae35ec4afaa6119b1645488ef3ac525bcf3 (diff) | |
| download | src-26fe2217bfbd6aa6ec67f5c57a2e7344bcf2fdff.tar.gz src-26fe2217bfbd6aa6ec67f5c57a2e7344bcf2fdff.zip | |
Only update the domain cursor once in keg_fetch_slab().
We drop the keg lock when we go to actually allocate the slab, allowing
other threads to advance the cursor. This can cause us to exit the
round-robin loop before having attempted allocations from all domains,
resulting in a hang during a subsequent blocking allocation attempt from
a depleted domain.
Reported and tested by: Jan Bramkamp <crest@bultmann.eu>
Reviewed by: alc, cem
Approved by: re (gjb)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D17209
Notes
Notes:
svn path=/head/; revision=338755
| -rw-r--r-- | sys/vm/uma_core.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/sys/vm/uma_core.c b/sys/vm/uma_core.c index 908349379763..937e78452021 100644 --- a/sys/vm/uma_core.c +++ b/sys/vm/uma_core.c @@ -2698,10 +2698,8 @@ again: LIST_INSERT_HEAD(&dom->ud_part_slab, slab, us_link); return (slab); } - if (rr) { - keg->uk_cursor = (keg->uk_cursor + 1) % vm_ndomains; - domain = keg->uk_cursor; - } + if (rr) + domain = (domain + 1) % vm_ndomains; } while (domain != start); /* Retry domain scan with blocking. */ |