Re: spin lock contention: lru_list lock

[David S. Miller]

   Date:   Sat, 19 Feb 2000 13:53:14 +0100
   From: Manfred Spraul <[e-mail]>

   I get extremely long hold times for the lru_list lock:

   sync_buffers(): up to 14 milliseconds, average 12 milliseconds. [called
   10 times per second.]
   __invalidate_buffers(): up to 8 milliseconds, average 7 milliseconds.[
   called ~4.5 times/sec]

A lock can be held for 2 minutes at a time, this isn't what matters.

Are you seeing "contention" for the lock?  That is what matters.

lru_list lock is the longest held mainly because it is the outermost
lock in the buffer cache locking hierarchy.

Later,
David S. Miller
[e-mail]