[PATCH RFC 0/3] nfsd: convert nfsd DRC code to use list_lru infrastructure

[Jeff Layton <jlayton@redhat.com>]

This patchset converts the LRU list in the nfsd duplicate reply cache to
use the new list_lru infrastrucure. Note that this is based on top of
the patch that I sent to Bruce earlier this week that fixes the
svc_cacherep direct reclaim bug. I'm sending this as an RFC since I'm
not 100% convinced it's an improvement.

The majorly unintuitive thing about list_lru that I've found is that
you can't call call list_lru_del from list_lru_walk. So, you need
different routines to free an object depending on how it's being freed.

Using list_lru also means extra spinlocking since we'd be moving to a
per-node LRU, but that's probably not a big deal since all of this is
done under the cache_lock anyway.

In any case, here's what a conversion to list_lru would look like...

Discuss!

Jeff Layton (3):
  nfsd: don't try to reuse an expired DRC entry off the list
  list_lru: add a new LRU_SKIP_REST lru_status value and handling
  nfsd: convert DRC code to use list_lru

 fs/nfsd/nfscache.c       | 130 +++++++++++++++++++++++++----------------------
 include/linux/list_lru.h |   2 +
 mm/list_lru.c            |   4 +-
 3 files changed, 75 insertions(+), 61 deletions(-)

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1.8.4.2