From: NeilBrown <neilb@suse.de>
To: Alexander Lyakas <alex.bolshoy@gmail.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: mdadm/Monitor.c - never removes MD devices from statelist
Date: Wed, 21 Sep 2011 15:06:13 +1000 [thread overview]
Message-ID: <20110921150613.74e044f0@notabene.brown> (raw)
In-Reply-To: <CAGRgLy4=dMRmqZW4_+Wv+0QZzanH_ZCX88xxL5QD2OK03GmYww@mail.gmail.com>
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On Mon, 12 Sep 2011 11:32:23 +0300 Alexander Lyakas <alex.bolshoy@gmail.com>
wrote:
> Hello Neil,
> yes, I will try to produce a patch (although I am using git, I have
> never done patches yet).
If you are using git, then patches are easy:
git show --format=email
>
> But I don't understand why do you require 'err' to be set. I would say
> that when there is a "DeviceDisappeared" event plus --scan is set,
> then you should remove. (And also perhaps if this array does not
> appear in the device list provided by the user).
A DeviceDisappeared event sets ->err to 1. So testing ->err is an easy way
to test if the device disappeated.
It doesn't matter if the device was listed by the user: if --scan is set we
will find it again anyway.
NeilBrown
>
> Alex.
>
>
> On Mon, Sep 12, 2011 at 6:36 AM, NeilBrown <neilb@suse.de> wrote:
> > On Sun, 11 Sep 2011 21:32:12 +0300 Alexander Lyakas <alex.bolshoy@gmail.com>
> > wrote:
> >
> >> Hi everybody,
> >> looking at the code of Monitor.c and doing some tests with it, I see
> >> that it is capable of detecting new arrays, when they appear in
> >> /proc/mdstat (if --scan is given). However, once array is added to
> >> 'statelist', it is never removed from there. Is this intentional?
> >> Perhaps only if --scan is given, and device disappears from
> >> /proc/mdstat, then it should be removed from monitoring, otherwise it
> >> could stick there forever, even though the array has been gone long
> >> time ago. And if it appears again, it will be picked up anyways.
> >>
> >
> > You are right - arrays are never removed.
> >
> > Is that a problem? Probably not, though I guess you could probably create
> > a scenario where there were lots of inactive devices cluttering memory.
> >
> > Is it worth fixing? I don't know - it depends on how intrusive the patch is.
> > We would only want to remove arrays with ->err set if 'scan' was set, but
> > when it is, it possible makes sense.
> >
> > Want to try creating a patch?
> >
> > NeilBrown
> >
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prev parent reply other threads:[~2011-09-21 5:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-11 18:32 mdadm/Monitor.c - never removes MD devices from statelist Alexander Lyakas
2011-09-12 3:36 ` NeilBrown
2011-09-12 8:32 ` Alexander Lyakas
2011-09-21 5:06 ` NeilBrown [this message]
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