On 10/12/2012 02:22 AM, Mathieu Desnoyers wrote: > * Lai Jiangshan ([email protected]) wrote: >> rculfstack is not really require RCU-only. >> >> 1) cds_lfs_push_rcu() don't need any lock, don't need RCU nor other locks. > > Good point ! I even documented this peculiarness in the > comment at the top of _cds_lfs_push_rcu(). > >> 2) cds_lfs_pop_rcu() don't only one of the following synchronization(not >> only RCU): >> A) use rcu_read_lock() to protect cds_lfs_pop_rcu() and use >> synchronize_rcu() >> or call_rcu() to free the popped node. (current comments said we >> need this >> synchronization, and thus we named this struct with rcu prefix. >> But actually, >> the followings are OK, and are more popular/friendly) >> B) use mutexs/locks to protect cds_lfs_pop_rcu(), we can free to >> free/modify the >> popped node any time, we don't need any synchronization when free >> them. >> C) only ONE thread can call cds_lfs_pop_rcu(). (multi-providers-single >> customer) >> D) others, like read-write locks. >> >> I consider B) and C) are more popular. In linux kernel, >> kernel/task_work.c uses a hybird ways of B) and C). >> >> I suggest to rename it, Or document B) and C) at least. > > Yes, agreed! Do you suggest we introduce a "lfstack", and slowly > deprecate rculfstack ? > > We could then document the various ways to protect "pop", and also > implement a "splice" operation while we are there. >
Acked. Thanks, Lai _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
