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author | Brian Behlendorf <[email protected]> | 2012-10-23 09:17:29 -0700 |
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committer | Brian Behlendorf <[email protected]> | 2012-10-23 09:36:19 -0700 |
commit | 71c9f0b00307e6ee703eef9eba91e7640731c458 (patch) | |
tree | 22829d5df4c548f911338dc4e981b9389322296a /include/sys/priv_impl.h | |
parent | 1e0c2c2ccfb720be81051a43c405fad173775963 (diff) |
Make kstat.ks_update() callback atomic
Move the kstat ks_update() callback under the ks_lock. This
enables dynamically sized kstats without modification to the
kstat API.
* Create a kstat with the KSTAT_FLAG_VIRTUAL flag.
* Register a ->ks_update() callback which does:
o Frees any existing ks_data buffer.
o Set ks_data_size to the kstat array size.
o Set ks_data to an allocated buffer of size ks_data_size
o Populate the array of buffers with the required data.
The buffer allocated in the ks_update() callback is guaranteed
to remain allocated and valid while the proc sequence handler
iterates over the buffer. The lock will not be dropped until
kstat_seq_stop() function is run making it safe for concurrent
access. To allow the ks_update() callback to perform memory
allocations the lock was changed to a mutex.
Signed-off-by: Brian Behlendorf <[email protected]>
Diffstat (limited to 'include/sys/priv_impl.h')
0 files changed, 0 insertions, 0 deletions