

Linux now free from Big Kernel Lock - kia
http://kernelnewbies.org/Linux_2_6_37#head-43fa76e538d9ff338cc8e80a281e83c1ddbb908a

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pmjordan
Well, almost:

" _Summary: Linux 2.6.37 includes several SMP scalability improvements for
Ext4 and XFS, an option to compile the kernel with the Big Kernel Lock
disabled_ "

It's still used in some old drivers and more importantly for file locking,
which obviously can't be used when the BKL isn't compiled in.

~~~
JoachimSchipper
Wait wait, this breaks _file locking_? Are you sure? It isn't in the linked
page, and it seems _too_ insane.

~~~
pmjordan
Follow the _commit_ link just below it:

[http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6...](http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=6de5bd128d381ad88ac6d419a5e597048eb468cf)

Quote:

 _The one exception is file locking, which is practically always enabled and
does a 'select BKL' instead. This effectively forces CONFIG_BKL to be enabled
until we have solved the fs/lockd mess and can apply the patch that removes
the BKL from fs/locks.c._

This is presumably why there hasn't been a big announcement by core kernel
hackers. After all, reduction in BKL use has been an ongoing effort for the
last half dozen or so releases and 2.6.37 is yet another milestone but not the
end of the road quite yet.

------
ehamberg
it sounds scarier than it is:

“all the critical Linux codepaths have been BKL-free for a long time”

