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From: Jan Engelhardt <jengelh@linux01.gwdg.de>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Tomas M <tomas@slax.org>, linux-kernel@vger.kernel.org
Subject: Re: max_loop limit
Date: Fri, 23 Mar 2007 02:34:04 +0100 (MET)	[thread overview]
Message-ID: <Pine.LNX.4.61.0703230232320.9555@yvahk01.tjqt.qr> (raw)
In-Reply-To: <20070322144210.73dfaf83.dada1@cosmosbay.com>


On Mar 22 2007 14:42, Eric Dumazet wrote:
>Instead of using :
>
>static struct loop_device *loop_dev;
>loop_dev = kmalloc(max_loop * sizeof(struct loop_device));
>
>Switch to :
>
>static struct loop_device **loop_dev;
>loop_dev = kmalloc(max_loop * sizeof(void *));
>if (!loop_dev) rollback...
>for (i = 0 ; i < max_loop ; i++) {
>	loop_dev[i] = kmalloc(sizeof(struct loop_device));
>	if (!loop_dev[i]) rollback...
>}
>
>This time, you would be limited to 16384 loop devices on x86_64, 32768 on i386
>:)

Oh noes. Please use a linked list (kmalloc cope = perfect) if you really need
loads of loopdevs. Sorta

 struct loopdev {
    struct list_head lh;
    int lo_number;
 };

to keep the /dev/loop%d number consistent across loopdev removal.
Maybe it's better to even use an rbtree (linked list does not scale to it).


Jan
-- 

  parent reply	other threads:[~2007-03-23  1:35 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-22  7:57 Tomas M
2007-03-22 11:00 ` markus reichelt
2007-03-22 11:37   ` Tomas M
2007-03-22 13:42     ` Eric Dumazet
2007-03-22 13:42       ` Jens Axboe
2007-03-22 13:52         ` Eric Dumazet
2007-03-22 13:54           ` Jens Axboe
2007-03-22 14:11             ` William Lee Irwin III
2007-03-22 15:22               ` Arjan van de Ven
2007-03-22 16:09               ` Pádraig Brady
2007-03-28 23:34                 ` Karel Zak
     [not found]             ` <20070322151826.c1421851.dada1@cosmosbay.com>
     [not found]               ` <20070322142306.GU19922@kernel.dk>
     [not found]                 ` <20070322153603.1f5d442d.dada1@cosmosbay.com>
2007-03-22 15:31                   ` max_loop limit - paid job offer Tomas M
2007-03-22 14:33         ` max_loop limit Al Viro
2007-03-22 19:51           ` Olivier Galibert
2007-03-22 14:25       ` Tomas M
2007-03-23  1:34       ` Jan Engelhardt [this message]
2007-03-23 23:26         ` [PATCH] " Jan Engelhardt
2007-03-25  0:17           ` Ken Chen
2007-03-25  0:29           ` Ken Chen
2007-03-25  8:40           ` Tomas M
2007-03-28 23:41             ` Karel Zak
2007-03-29  3:54           ` Kyle Moffett
2007-03-29  4:16             ` [PATCH] max_loop limit, t2 Jan Engelhardt
2007-03-29  8:38               ` [PATCH] max_loop limit, loop.c final working version Tomas M
2007-03-29 14:16     ` max_loop limit Bill Davidsen
2007-03-22 13:53 devzero
2007-03-22 23:23 devzero
2007-03-23  8:59 ` Tomas M
2007-03-22 23:37 roland
2007-03-29 14:20 ` Bill Davidsen

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