From: Russell King <rmk@arm.linux.org.uk>
To: hugh@veritas.com (Hugh Dickins)
Cc: alan@lxorguk.ukuu.org.uk (Alan Cox),
tytso@mit.edu (Theodore Ts'o),
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] alloc_tty_struct() wastage?
Date: Fri, 2 Mar 2001 23:37:26 +0000 (GMT) [thread overview]
Message-ID: <200103022337.XAA01526@raistlin.arm.linux.org.uk> (raw)
In-Reply-To: <Pine.LNX.4.21.0103022326070.1719-100000@localhost.localdomain> from "Hugh Dickins" at Mar 02, 2001 11:29:02 PM
Hugh Dickins writes:
> I've been puzzling over alloc_tty_struct(), which seems determined
> to waste memory on a machine of page size 8KB.
Maybe you could change the ">" to ">="?
> I've come to the conclusion that it represents great caution on
> Russell's part when introducing ARM, not to interfere with
> existing code of other architectures - is that so, Russell?
My understanding of the usage of get_free_page there is as follows:
The problem was that sizeof(struct tty_struct) was very close to
the page size of x86 machines (4K), and kmalloc wasted space
unnecessarily. Therefore get_free_page was used by x86 to allocate
this structure. I think I'm right in saying that allocating
anything larger than half your page size is best done with
get_free_page.
Someone will probably correct me on that comment above though.
Can someone confirm please: is it safe and reasonable to use
kmalloc on allocating tty_struct on all architectures now?
--
Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux
http://www.arm.linux.org.uk/personal/aboutme.html
prev parent reply other threads:[~2001-03-02 23:38 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-03-02 17:47 Linux 2.4.2ac9 Alan Cox
2001-03-02 21:37 ` [PATCH] QIC-02 tape broken buffaddr Hugh Dickins
2001-03-05 15:52 ` lvm_snap calc_max_buckets num_physpages Hugh Dickins
2001-03-05 15:55 ` netfilter ip_conntrack num_physpages Hugh Dickins
2001-03-29 14:20 ` [PATCH] sparc64 module_map dont vfree Hugh Dickins
2001-04-17 14:00 ` [PATCH] emu10k1/audio un reserve Hugh Dickins
2001-03-02 21:39 ` [PATCH] CS89x0 demands too many pages Hugh Dickins
2001-03-03 12:39 ` [PATCH] cs89x0.c Andrew Morton
2001-03-02 21:41 ` [PATCH] getname() buffer overflow Hugh Dickins
2001-03-02 23:29 ` [PATCH] alloc_tty_struct() wastage? Hugh Dickins
2001-03-02 23:37 ` Russell King [this message]
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