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author | attilio <attilio@FreeBSD.org> | 2010-01-07 01:19:01 +0000 |
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committer | attilio <attilio@FreeBSD.org> | 2010-01-07 01:19:01 +0000 |
commit | 80498ec26cbddc4754bb64a55078d6364878a881 (patch) | |
tree | 25647384888806c4bc594e15fbf1bdbc0330f281 /sys/kern | |
parent | 5d0cfcfe1ddc88db5f4d35bf5376a4c8d2147efc (diff) | |
download | FreeBSD-src-80498ec26cbddc4754bb64a55078d6364878a881.zip FreeBSD-src-80498ec26cbddc4754bb64a55078d6364878a881.tar.gz |
Tweak comments.
Diffstat (limited to 'sys/kern')
-rw-r--r-- | sys/kern/kern_lock.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/sys/kern/kern_lock.c b/sys/kern/kern_lock.c index 6783a43..0d0444f 100644 --- a/sys/kern/kern_lock.c +++ b/sys/kern/kern_lock.c @@ -277,6 +277,11 @@ wakeupshlk(struct lock *lk, const char *file, int line) * avoid a starvation for the threads sleeping on the shared * queue by giving them precedence and cleaning up the * exclusive waiters bit anyway. + * Please note that lk_exslpfail count may be lying about + * the real number of waiters with the LK_SLEEPFAIL flag on + * because they may be used in conjuction with interruptible + * sleeps so lk_exslpfail is consider as a 'upper limit' + * bound, considering the edge cases. */ realexslp = sleepq_sleepcnt(&lk->lock_object, SQ_EXCLUSIVE_QUEUE); @@ -943,6 +948,12 @@ __lockmgr_args(struct lock *lk, u_int flags, struct lock_object *ilk, * empty avoid a starvation for the threads sleeping * on the shared queue by giving them precedence * and cleaning up the exclusive waiters bit anyway. + * Please note that lk_exslpfail count may be lying + * about the real number of waiters with the + * LK_SLEEPFAIL flag on because they may be used in + * conjuction with interruptible sleeps so + * lk_exslpfail is consider as a 'upper limit' bound, + * considering the edge cases. */ MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); realexslp = sleepq_sleepcnt(&lk->lock_object, @@ -1046,6 +1057,13 @@ __lockmgr_args(struct lock *lk, u_int flags, struct lock_object *ilk, * threads sleeping on the shared queue by * giving them precedence and cleaning up the * exclusive waiters bit anyway. + * Please note that lk_exslpfail count may be + * lying about the real number of waiters with + * the LK_SLEEPFAIL flag on because they may + * be used in conjuction with interruptible + * sleeps so lk_exslpfail is consider as a + * 'upper limit' bound, considering the edge + * cases. */ if (v & LK_EXCLUSIVE_WAITERS) { queue = SQ_EXCLUSIVE_QUEUE; |