From: Dave Jones <davej@redhat.com>
To: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: potential for buffer_head shrinkage.
Date: Fri, 29 Dec 2006 21:45:54 -0500 [thread overview]
Message-ID: <20061230024554.GA12306@redhat.com> (raw)
Looking at struct buffer_head, it seems that b_state
uses at most 15 bits, where it's defined as a 64bit entity
due to it being used by bit_spin_lock and friends.
Given it's not uncommon for a few hundred thousand of these
to be present, I wonder if it's worth the effort of folding
b_count into the upper bits of b_state, thus shrinking
buffer_head by 16 bits? This would still leave 32 bits
'wasted' for further bh_state_bits expansion if necessary.
Opinions?
Dave
--
http://www.codemonkey.org.uk
next reply other threads:[~2006-12-30 2:45 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-30 2:45 Dave Jones [this message]
2006-12-30 2:50 ` potential for buffer_head shrinkage Dave Jones
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