2010-11-16 08:19:18

by Alexander V. Lukyanov

[permalink] [raw]
Subject: PATCH: allow inode_readahead_blks=0

Hello!

Currently the value 0 is disallowed, as it is not a power of 2.

This obvious patch fixes the problem.

--
Alexander.


Attachments:
(No filename) (130.00 B)
diff (608.00 B)
Download all attachments

2010-11-17 07:49:24

by Alexander V. Lukyanov

[permalink] [raw]
Subject: Re: PATCH: allow inode_readahead_blks=0

On Tue, Nov 16, 2010 at 11:05:46AM +0300, Alexander V. Lukyanov wrote:
> Currently the value 0 is disallowed, as it is not a power of 2.

BTW, the default value inode_readahead_blks=32 gives me troubles: it raises
load average and increases request latency on a busy squid server. I
explain it by random access to large number of files which are present in
the squid cache.

BTW2: the value of 0 should be allowed, it is explicitly used by the code:
/*
* If we need to do any I/O, try to pre-readahead extra
* blocks from the inode table.
*/
if (EXT4_SB(sb)->s_inode_readahead_blks) {
...
}
--
Alexander.