On Sun, 03 Dec 2006 12:49:42 -0500Just saw you suggested the "next door" LKML thread ("la la la la ... swappiness") to use "-o sync" ? Well, now I do see you're determined ... anyway, I think I got my stuff working without this kernel patch ... still under testing though.
Wendy Cheng <wcheng@xxxxxxxxxx> wrote:
I read this as "It is ok to give system admin(s) commands (that this "drop_pagecache_sb() call" is all about) to drop page cache. It is, however, not ok to give filesystem developer(s) this very same function to trim their own page cache if the filesystems choose to do so" ?
If you're referring to /proc/sys/vm/drop_pagecache then no, that isn't for
administrators - it's a convenience thing for developers, to get repeatable
benchmarks. Attempts to make it a per-numa-node control for admin purposes have
been rejected.
Yes, dentries are part of the logic (during lookup time) but book-keepings (reference count, reclaim, delete, etc) are all done thru inode structures.[snip] .......hmm, I suppose that makes sense.
Are there dentries associated with these locks?
Yes, just found the new DLM uses "jhash" call (include/linux/jhash.h). I'm on an older version of DLM that uses FNV hash algorithm (http://www.isthe.com/chongo/tech/comp/fnv/). Will do some performance test runs to compare these two methods.
Did you look at improving that lock-lookup algorithm, btw? Core kernel has
no problem maintaining millions of cached VFS objects - is there any reason
why your lock lookup cannot be similarly efficient?