path: root/fs/ext3/super.c
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authorTejun Heo <tj@kernel.org>2014-09-20 01:27:25 -0400
committerTejun Heo <tj@kernel.org>2014-09-20 01:27:25 -0400
commite625305b390790717cf2cccf61efb81299647028 (patch)
tree87bde164e935bf06fca1b4adfa26d23f1cca4238 /fs/ext3/super.c
parentpercpu-refcount: improve WARN messages (diff)
percpu-refcount: make percpu_ref based on longs instead of ints
percpu_ref is currently based on ints and the number of refs it can cover is (1 << 31). This makes it impossible to use a percpu_ref to count memory objects or pages on 64bit machines as it may overflow. This forces those users to somehow aggregate the references before contributing to the percpu_ref which is often cumbersome and sometimes challenging to get the same level of performance as using the percpu_ref directly. While using ints for the percpu counters makes them pack tighter on 64bit machines, the possible gain from using ints instead of longs is extremely small compared to the overall gain from per-cpu operation. This patch makes percpu_ref based on longs so that it can be used to directly count memory objects or pages. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Kent Overstreet <kmo@daterainc.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
Diffstat (limited to 'fs/ext3/super.c')
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