(resent to list)
Dear Wolfgang Denk,
Am 29.09.2010 um 22:01 schrieb Wolfgang Denk:
Dear =?UTF-8?q?Andreas=20Bie=C3=9Fmann?=,
In message 1285788486-43901-1-git-send-email-andreas.devel@googlemail.com you wrote:
[snip]
* 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).
** But in some cases it is necessary to have another algorithm to* get the size of hash table. Especially for extremely small buffers* there is the flag H_ALG_SMALL_BUF which takes another factor to* calculate the hash table size.*/
if (!htab->table) {
int nent = size / 8;
int nent;if (flag & H_ALG_SMALL_BUF)nent = size / 2;elsenent = size / 8;Did you read the comment above?
Yes, I did.
With your configuration, importing a 64 kB environment buffer would result in 32 k entries in the hash table.
Well therefore we have another 'algorithm' implemented to cope with this. The flag H_ALG_SMALL_BUF should be set especially when importing a small buffer. Anyhow the maximum limit some lines below will never be exceeded.
This obviously makes no sense.
I think we should rather make sure that a certain minimum of entries will always be available, for exmaple something like this:
int nent = 64 + size / 8;
This sounds also good but why do not calculate as before and after that check some (maybe definable) borders?
How about: int nent = size / 8; if (nent < CONFIG_ENV_MIN_ENTRIES) nent = CONFIG_ENV_MIN_ENTRIES; ...
or similar.
What do you think?
How about my suggestion?
[Actually I think the current setting (size / 8) is _way_ too conservative in most cases. eventually we'd really be better off with something like "64 + size / 32" or so. I'm interested in feedback - the statistics I have about environment settings (number of entries versus total size) is unfortunately a bit limited, and since most of the boards come from the same hands they follow a common style, which eventually is not what other users do.]
Well in most cases the environment needs a static size. The actual size of environment has (in my view) no/small connection to space for environment in NV memory. In most cases the space reserved for environment is way to big cause of sector boundaries. Therefore I think it would meet the needs when we have one (configurable) size for hash table without the calculation.
regards
Andreas Bießmann
Best regards,
Wolfgang Denk
-- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de As far as we know, our computer has never had an undetected error. -- Weisert