From: James Bottomley <James.Bottomley@SteelEye.com>
To: Andrew Morton <akpm@osdl.org>
Cc: luben_tuikov@adaptec.com, jim.houston@ccur.com,
Linux Kernel <linux-kernel@vger.kernel.org>,
SCSI Mailing List <linux-scsi@vger.kernel.org>,
Dave Jones <davej@redhat.com>, Jeff Garzik <jgarzik@pobox.com>
Subject: Re: [PATCH 2.6.12.5 1/2] lib: allow idr to be used in irq context
Date: Mon, 22 Aug 2005 09:28:58 -0500 [thread overview]
Message-ID: <1124720938.5211.13.camel@mulgrave> (raw)
In-Reply-To: <20050821205214.2a75b3cf.akpm@osdl.org>
On Sun, 2005-08-21 at 20:52 -0700, Andrew Morton wrote:
> erp. posix_timers has its own irq-safe lock, so we're doing extra,
> unneeded locking in that code path.
Possibly, the posix timer code is rather convoluted in this area so I'm
not entirely sure my analysis is correct.
> I think providing locking inside idr.c was always a mistake - generally we
> rely on caller-provided locking for such things.
Well, the reason is because they wanted lockless pre-alloc. If you do
it locked, you can't use GFP_KERNEL for the memory allocation flag which
rather defeats its purpose.
Perhaps the bug is in the API. We have pre-allocate, new, find and
remove. Perhaps what we're missing is a reuse all of which could then
rely on caller provided locking, with pre-alloc and remove requiring
user context but new, find and reuse being happy in irq context.
James
next prev parent reply other threads:[~2005-08-22 21:35 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-16 22:03 [PATCH 2.6.12.5 1/2] lib: allow idr to be used in irq context Luben Tuikov
2005-08-17 16:01 ` Jim Houston
2005-08-21 8:25 ` Andrew Morton
2005-08-21 15:49 ` Luben Tuikov
2005-08-21 16:06 ` James Bottomley
2005-08-21 17:27 ` Luben Tuikov
2005-08-21 22:03 ` James Bottomley
2005-08-22 0:33 ` Luben Tuikov
2005-08-22 3:15 ` James Bottomley
2005-08-22 3:52 ` Andrew Morton
2005-08-22 14:28 ` James Bottomley [this message]
2005-08-22 16:51 ` Luben Tuikov
2005-08-22 21:53 ` James Bottomley
2005-08-22 22:09 ` Andrew Morton
2005-08-23 17:15 ` James Bottomley
2005-08-22 16:33 ` Luben Tuikov
2005-08-22 14:06 ` Luben Tuikov
-- strict thread matches above, loose matches on Subject: below --
2005-08-21 20:40 Luben Tuikov
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