[PATCH 3/6] fs: Introduce a per_cpu last_ino allocator

new_inode() dirties a contended cache line to get inode numbers.

Solve this problem by providing to each cpu a per_cpu variable,
feeded by the shared last_ino, but once every 1024 allocations.

This reduce contention on the shared last_ino.

Note : last_ino_get() method must be called with preemption
disabled on SMP.


(socket8 bench result : no differences, but this is because inode_lock
cost is too heavy)

Signed-off-by: Eric Dumazet <redacted>
---
 fs/inode.c |   27 +++++++++++++++++++++++++--
 1 files changed, 25 insertions(+), 2 deletions(-)