new_inode() dirties a contended cache line to get increasing
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, and give same
spreading ino numbers than before.
(same wraparound after 2^32 allocations)

Signed-off-by: Eric Dumazet <redacted>
---
 fs/inode.c |   35 ++++++++++++++++++++++++++++++++---
 1 files changed, 32 insertions(+), 3 deletions(-)