Performance optimization is 15% brains, 85% black magic. I could easily
imagine that in many conditions, the extra locked-down free buffers
improve performance by making a pool of quick-allocation free buffers
available, even at the expense of other things.
> i'm genuinely curious to know, btw, what pathological conditions
> do you think might cause a catastrophic memory shortage?
I said they were unlikely..
Basically, the only real case I can imagine where this actually could
result in serious problems is:
- write a large file that fills much of your memory because you're not
doing anything else.
- remove the file.
- start applications that do _not_ do any writes to the filesystem, but
use lots of memory other ways..
> the best solution is to figure out how to allow page stealing while not
> disturbing the LRU queues in the buffer cache.
Indeed. Leaving the b_count at an elevated number may give you some of
that advantage, but it's definitely not something I want to count on for
good behaviour..
Linus
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