* Waiman Long <[email protected]> wrote: > As there is concern that the larger pcpu_list_node structure and the > per-cpu overhead may be a waste of resource on small system. This patch > adds a config parameter CONFIG_PERCPU_LIST to disable the per-cpu list > if the kernel builder chooses to do so. With per-cpu list disabled, > all the different groups of per-cpu lists will be degenerated into > global lists for all the CPUs. > > The current default is to enable per-cpu list. A kernel builder needs > to explicitly turn it off. > > Signed-off-by: Waiman Long <[email protected]> > --- > fs/inode.c | 2 +- > include/linux/percpu-list.h | 93 > ++++++++++++++++++++++++++++++++++++++++++- > lib/Kconfig | 14 ++++++ > lib/percpu-list.c | 24 +++++++++++- > 4 files changed, 130 insertions(+), 3 deletions(-)
I think this kind of #ifdef complexity and the doubling of our Kconfig and testing space is counterproductive, and I think the per CPU locking is a win on as small as dual core CPUs, and on UP CPUs the per CPU list becomes a single global list automatically. I'm not against visible memory savings for overly clever scalability features, but this does not appear to be such a case, so: NAKed-by: Ingo Molnar <[email protected]> Thanks, Ingo
