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 Bießmann andreas.devel@googlemail.com --- v2: implement as suggested by Wolfgang
lib/hashtable.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/lib/hashtable.c b/lib/hashtable.c index b747f1f..57802cf 100644 --- a/lib/hashtable.c +++ b/lib/hashtable.c @@ -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;