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From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Kent Overstreet <koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org,
	Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Mikulas Patocka
	<mpatocka-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	bharrosh-C4P08NqkoRlBDgjK7y7TUQ@public.gmane.org,
	david-FqsqvQoI3Ljby3iVrkZq2A@public.gmane.org
Subject: Re: [PATCH 2/2] block: Avoid deadlocks with bio allocation by stacking drivers
Date: Mon, 10 Sep 2012 13:40:10 -0700	[thread overview]
Message-ID: <20120910204010.GA32310@google.com> (raw)
In-Reply-To: <20120910202435.GG16360-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>

Hello, Kent.

On Mon, Sep 10, 2012 at 01:24:35PM -0700, Kent Overstreet wrote:
> And at that point, why duplicate that line of code? It doesn't matter that
> much, but IMO a goto retry better labels what's actually going on (it's
> something that's not uncommon in the kernel and if I see a retry label
> in a function I pretty immediately have an idea of what's going on).
> 
> So we could do
> 
> retry:
> p = mempool_alloc(bs->bio_pool, gfp_mask);
> if (!p && gfp_mask != saved_gfp) {
> 	punt_bios_to_rescuer(bs);
> 	gfp_mask = saved_gfp;
> 	goto retry;
> }

Yes, we do retry loops if that makes the code simpler.  Doing that to
save one extra alloc call, I don't think so.

Thanks.

-- 
tejun

  parent reply	other threads:[~2012-09-10 20:40 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-07 22:12 [PATCH 0/2] Avoid deadlocks with bio allocation Kent Overstreet
     [not found] ` <1347055973-11581-1-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-07 22:12   ` [PATCH 1/2] block: Reorder struct bio_set Kent Overstreet
2012-09-07 22:12 ` [PATCH 2/2] block: Avoid deadlocks with bio allocation by stacking drivers Kent Overstreet
     [not found]   ` <1347055973-11581-3-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-08 19:36     ` Tejun Heo
     [not found]       ` <20120908193641.GB12773-RcKxWJ4Cfj1J2suj2OqeGauc2jM2gXBXkQQo+JxHRPFibQn6LdNjmg@public.gmane.org>
2012-09-10  0:28         ` Kent Overstreet
     [not found]           ` <20120910002810.GA23241-jC9Py7bek1znysI04z7BkA@public.gmane.org>
2012-09-10 15:25             ` Vivek Goyal
2012-09-10 17:22             ` Tejun Heo
     [not found]               ` <20120910172210.GC14103-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-10 20:24                 ` Kent Overstreet
     [not found]                   ` <20120910202435.GG16360-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-10 20:40                     ` Tejun Heo [this message]
     [not found]                       ` <20120910204010.GA32310-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-10 21:33                         ` Kent Overstreet
     [not found]                           ` <20120910213349.GH16360-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-10 21:37                             ` Tejun Heo
2012-09-10 21:56                               ` Kent Overstreet
     [not found]                                 ` <20120910215633.GA19739-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-10 22:09                                   ` Tejun Heo
     [not found]                                     ` <20120910220910.GB7677-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-10 22:50                                       ` [dm-devel] " Alasdair G Kergon
     [not found]                                         ` <20120910225057.GA10477-FDJ95KluN3Z0klwcnFlA1dvLeJWuRmrY@public.gmane.org>
2012-09-10 23:01                                           ` Tejun Heo
2012-09-10 23:06                                             ` Kent Overstreet
     [not found]                                             ` <CAOS58YO5puV2iPhwe0vbyEydPnR=eWPStNRm=xEpMeo-TMHCaw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-09-10 23:09                                               ` Alasdair G Kergon
     [not found]                                                 ` <20120910230917.GB10477-FDJ95KluN3Z0klwcnFlA1dvLeJWuRmrY@public.gmane.org>
2012-09-10 23:35                                                   ` Tejun Heo
     [not found]                                                     ` <20120910233502.GH7677-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-10 23:45                                                       ` Alasdair G Kergon
2012-09-10 23:01                                           ` Kent Overstreet
2012-09-10 23:13                                       ` Tejun Heo
2012-09-11 18:36                                   ` Muthu Kumar
     [not found]                                     ` <CAFR8ued=Le4B4i_Rf4eECXsVgKvce9J7bO9sDSS91PFzBZ6j5w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-09-11 18:45                                       ` Tejun Heo
     [not found]                                         ` <20120911184553.GT7677-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-11 18:58                                           ` Muthu Kumar
2012-09-11 19:31                                             ` Kent Overstreet
     [not found]                                               ` <20120911193124.GI19739-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-11 20:00                                                 ` Muthu Kumar

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