Re: buffer cache behavior on memory-constrained systems (fwd)

Chuck Lever (cel@monkey.org)
Sat, 27 Mar 1999 14:38:11 -0500 (EST)

On Sat, 27 Mar 1999, Andrea Arcangeli wrote:
> Note that you should also revert to freeing at least the freelist (this is
> the reason Linus posted the patch against 2.2.4) and all other lru-list if
> the BUF_CLEAN is empty.
>
> But more important you could have the first entry in the lru list not
> freeable (don't ask me why ;), and in such case you would have big
> stability problems.

in which case you'd probably see some "out of memory" errors.

> Note that in ftp://e-mind.com/pub/linux/andrea-tree/2.2.4_andrea3.bz2 I am
> just freeing pages in shrink_mmap() in perfect lru basis (taking care also
> of buffer aging). But I am doing it at the pagemap level. I see it far
> more clean and general. I am touching the buffer not in bread but in
> get_hash_table and in getblk if the buffer is not found in the hash table.

nice work, andrea...

i've only tried this patch for a short time, but it seems to exhibit lots
of desirable characteristics when memory becomes constrained. i'll take a
closer look at it as soon as i have time.

- Chuck Lever

--
corporate:	<chuckl@netscape.com>
personal:	<chucklever@netscape.net> or <cel@monkey.org>


The Linux Scalability project:
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