Messages in this thread | | | Date | Thu, 21 Oct 2004 14:29:32 -0400 | Subject | Re: [patch] Real-Time Preemption, -RT-2.6.9-rc4-mm1-U8 | From | Scott Wood <> |
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On Thu, Oct 21, 2004 at 10:10:17PM +0400, Eugeny S. Mints wrote: > Scott Wood wrote: > >If you keep it in priority order, then you're paying the O(n) cost > >every time you acquire a lock. If you keep it unordered and only > >search it when you need to recalculate a task's priority after a lock > >has been released (or priorities have been changed), you pay the cost > >much less often. Plus, the number of locks held by any given thread > >should generally be very small. > As to locks held by any given thread - it's not always true - take a > look at mm/filemap.c locks nesting map in comments.
I guess it depends on the definition of "very small" and "generally". :-)
A nesting of 5 locks is pushing the limits of "very small", but it's still no big deal to iterate over once in a while.
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