Hi Neil, all,
The nfs daemons run holding the global kernel lock. They still hold
this lock over calls to file_op's read and write.
The file system kernel interface (FSKI) doesn't require the kernel lock
to be held over these read/write calls. The nfs daemons do not require
that the reads or writes do not block (would be v silly if they did), so
they have no guarantee the lock isn't dropped and retaken during
blocking. ie. they aren't using it as a guard across the calls.
Dropping the kernel lock around read and write in fs/nfsd/vfs.c is a
_big_ SMP scalability win!
Attached patch is against 2.4.1-ac18, but should apply to most recent
kernel versions.
Mark
This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 21:00:18 EST