rhashtable: Add nested tables

Browse source

This patch adds code that handles GFP_ATOMIC kmalloc failure on
insertion.  As we cannot use vmalloc, we solve it by making our
hash table nested.  That is, we allocate single pages at each level
and reach our desired table size by nesting them.

When a nested table is created, only a single page is allocated
at the top-level.  Lower levels are allocated on demand during
insertion.  Therefore for each insertion to succeed, only two
(non-consecutive) pages are needed.

After a nested table is created, a rehash will be scheduled in
order to switch to a vmalloced table as soon as possible.  Also,
the rehash code will never rehash into a nested table.  If we
detect a nested table during a rehash, the rehash will be aborted
and a new rehash will be scheduled.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

...

This commit is contained in:

Herbert Xu 2017-02-11 19:26:47 +08:00 • committed by David S. Miller

parent 40f9f43970

commit da20420f83

2 changed files with 276 additions and 72 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

78

include/linux/rhashtable.h

View file

270

lib/rhashtable.c

View file