lib/hashtable.c: add CONFIG_ENV_MIN_ENTRIES

This patch adds a new config parameter for adjusting the calculation of
hash table size when importing a buffer.

When importing a extremely small buffer (e.g. the default_environment)
the old calculation generated a hash table which could hold at most the
buffer content but no more entires.

The new calculation add a fixed number of entries to the result to fit
better for small import buffers. This amount may be configured by the
user in board file to adjust the behaviour.

Signed-off-by: Andreas Biemann <andreas.devel@googlemail.com>
This commit is contained in:
Andreas Bießmann 2010-10-01 22:51:02 +02:00 committed by Wolfgang Denk
parent f44a928e7e
commit fc5fc76bda

View file

@ -45,6 +45,9 @@
# include <linux/string.h>
#endif
#ifndef CONFIG_ENV_MIN_ENTRIES /* minimum number of entries */
#define CONFIG_ENV_MIN_ENTRIES 64
#endif
#ifndef CONFIG_ENV_MAX_ENTRIES /* maximum number of entries */
#define CONFIG_ENV_MAX_ENTRIES 512
#endif
@ -647,13 +650,14 @@ int himport_r(struct hsearch_data *htab,
* (CONFIG_ENV_SIZE). This heuristics will result in
* unreasonably large numbers (and thus memory footprint) for
* big flash environments (>8,000 entries for 64 KB
* envrionment size), so we clip it to a reasonable value
* (which can be overwritten in the board config file if
* needed).
* envrionment size), so we clip it to a reasonable value.
* On the other hand we need to add some more entries for free
* space when importing very small buffers. Both boundaries can
* be overwritten in the board config file if needed.
*/
if (!htab->table) {
int nent = size / 8;
int nent = CONFIG_ENV_MIN_ENTRIES + size / 8;
if (nent > CONFIG_ENV_MAX_ENTRIES)
nent = CONFIG_ENV_MAX_ENTRIES;