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Jeff Dike authored
This adds VM op batching to skas0. Rather than having a context switch to and from the userspace stub for each address space change, we write a number of operations to the stub data page and invoke a different stub which loops over them and executes them all in one go. The operations are stored as [ system call number, arg1, arg2, ... ] tuples. The set is terminated by a system call number of 0. Single operations, i.e. page faults, are handled in the old way, since that is slightly more efficient. For a kernel build, a minority (~1/4) of the operations are part of a set. These sets averaged ~100 in length, so for this quarter, the context switching overhead is greatly reduced. Signed-off-by:
Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
c5600490