obsolete option freelist_percent in documentation / question

[Ronald van Zantvoort <ronald@pcextreme.nl>]

Hi all,


https://www.kernel.org/doc/Documentation/bcache.txt reports

freelist_percent
   Size of the freelist as a percentage of nbuckets. Can be written to to
   increase the number of buckets kept on the freelist, which lets you
   artificially reduce the size of the cache at runtime. Mostly for testing
   purposes (i.e. testing how different size caches affect your hit 
rate), but
   since buckets are discarded when they move on to the freelist will 
also make
   the SSD's garbage collection easier by effectively giving it more 
reserved
   space.


However, on dec. 17, 2013, the allocator reserves got reworked and this 
option disappeared.

We're currently rolling out bcache on a number of older Intel SSD's 
which are notoriously bad on the GC part; they practically *need* a big 
chunk of reserved space to function properly.

Of course we could go with a HPA or a smaller partition, but it'd be 
much more elegant to do this from within bcache itself; so is this still 
possible , now that this option obviously no longer exists, and if so, how?

Thanks in advance!

Ronald