Messages in this thread | | | From | Waiman Long <> | Subject | [RFC PATCH 0/2] percpu_counter: Enable switching to global counter | Date | Fri, 4 Mar 2016 21:51:37 -0500 |
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This patchset allows the degeneration of per-cpu counters back to global counters when:
1) The number of CPUs in the system is large, hence a high cost for calling percpu_counter_sum(). 2) The initial count value is small so that it has a high chance of excessive percpu_counter_sum() calls.
When the above 2 conditions are true, this patchset allows the user of per-cpu counters to selectively degenerate them into global counters with lock. This is done by calling the new percpu_counter_set_limit() API after percpu_counter_set(). Without this call, there is no change in the behavior of the per-cpu counters.
Patch 1 implements the new percpu_counter_set_limit() API.
Patch 2 modifies XFS to call the new API for the m_ifree and m_fdblocks per-cpu counters.
Waiman Long (2): percpu_counter: Allow falling back to global counter on large system xfs: Allow degeneration of m_fdblocks/m_ifree to global counters
fs/xfs/xfs_mount.c | 1 - fs/xfs/xfs_mount.h | 5 +++ fs/xfs/xfs_super.c | 6 +++ include/linux/percpu_counter.h | 10 +++++ lib/percpu_counter.c | 72 +++++++++++++++++++++++++++++++++++++++- 5 files changed, 92 insertions(+), 2 deletions(-)
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