linux/drivers/base/regmap
Lars-Peter Clausen 472fdec738 regmap: rbtree: Reduce number of nodes, take 2
Support for reducing the number of nodes and memory consumption of the rbtree
cache by allowing for small unused holes in the node's register cache block was
initially added in commit 0c7ed856 ("regmap: Cut down on the average # of nodes
in the rbtree cache"). But the commit had problems and so its effect was
reverted again in commit 4e67fb5 ("regmap: rbtree: Fix overlapping rbnodes.").
This patch brings the feature back of reducing the average number of nodes,
which will speedup node look-up, while at the same time also reducing the memory
usage of the rbtree cache. This patch takes a slightly different approach than
the original patch though. It modifies the adjacent node look-up to not only
consider nodes that are just one to the left or the right of the register but
any node that falls in a certain range around the register. The range is
calculated based on how much memory it would take to allocate a new node
compared to how much memory it takes adding a set of unused registers to an
existing node. E.g. if a node takes up 24 bytes and each register in a block
uses 1 byte the range will be from the register address - 24 to the register
address + 24. If we find a node that falls within this range it is cheaper or as
expensive to add the register to the existing node and have a couple of unused
registers in the node's cache compared to allocating a new node.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-08-29 13:32:40 +01:00
..
internal.h regmap: fix regcache_reg_present() for empty cache 2013-08-09 12:47:29 +01:00
Kconfig regmap: select REGMAP if REGMAP_MMIO and REGMAP_IRQ enabled 2012-10-17 22:09:35 +09:00
Makefile regmap: flat: Add flat cache type 2013-01-02 10:58:53 +00:00
regcache-flat.c regmap: flat: Add flat cache type 2013-01-02 10:58:53 +00:00
regcache-lzo.c regmap: cache: Pass the map rather than the word size when updating values 2013-03-04 10:30:27 +08:00
regcache-rbtree.c regmap: rbtree: Reduce number of nodes, take 2 2013-08-29 13:32:40 +01:00
regcache.c Merge remote-tracking branch 'regmap/topic/cache' into regmap-rbtree 2013-08-29 13:32:36 +01:00
regmap-debugfs.c Merge remote-tracking branch 'regmap/topic/debugfs' into regmap-next 2013-06-30 12:40:02 +01:00
regmap-i2c.c i2c: Split I2C_M_NOSTART support out of I2C_FUNC_PROTOCOL_MANGLING 2012-05-30 10:55:34 +02:00
regmap-irq.c regmap: irq: Clarify error message when we fail to request primary IRQ 2013-03-19 10:50:56 +00:00
regmap-mmio.c regmap: mmio: add register clock support 2013-02-14 16:40:28 +00:00
regmap-spi.c regmap: spi: Handle allocation failures gracefully 2013-02-05 14:14:32 +00:00
regmap.c regmap: regcache: allow read-only regs to be cached 2013-08-09 12:47:29 +01:00