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Date:      Sat, 27 Sep 2014 20:55:52 -0500
From:      Bryan Venteicher <bryanv@daemoninthecloset.org>
To:        Steven Hartland <killing@multiplay.co.uk>
Cc:        "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>
Subject:   Re: Change uma_mtx to rwlock
Message-ID:  <CAMo0n6QMogoNS-X0exL-LHc_pymRGDA1kn408KF59XgJ1qRQtw@mail.gmail.com>
In-Reply-To: <CF61374E89D8461093CEDB42D4FCBABE@multiplay.co.uk>
References:  <CAMo0n6Q=P5H3%2BCqr8KjFRVLvWHZfJYnROVe4xF3DmKw95D%2B5zQ@mail.gmail.com> <CF61374E89D8461093CEDB42D4FCBABE@multiplay.co.uk>

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On Sat, Sep 27, 2014 at 8:42 PM, Steven Hartland <killing@multiplay.co.uk>
wrote:

> Out of interest does that include ZFS and its UMA zones, as we're current=
ly
> investigating issues around this.
>
>
=E2=80=8BYes, I believe this would include ZFS's zones too.=E2=80=8B



>    Regards
>    Steve
>
> ----- Original Message ----- From: "Bryan Venteicher" <
> bryanv@daemoninthecloset.org>
> To: <freebsd-hackers@freebsd.org>
> Sent: Sunday, September 28, 2014 1:59 AM
> Subject: Change uma_mtx to rwlock
>
>
>
>  Hi,
>>
>> I'd appreciate some comments attached patch that changes the uma_mtx to =
a
>> rwlock.
>>
>> At $JOB, we have machines with ~400GB RAM, with much of that being
>> allocated through UMA zones. We've observed that timeouts were sometimes
>> unexpectedly delayed by a half second or more. We tracked one of the
>> reasons for this down to when the page daemon was running, calling
>> uma_reclaim() -> zone_foreach(). zone_foreach() holds the uma_mtx while
>> zone_drain()'ing each zone. If uma_timeout() fires, it will block on the
>> uma_mtx when it tries to zone_timeout() each zone.
>>
>>
>
> ------------------------------------------------------------
> --------------------
>
>
>  _______________________________________________
>> freebsd-hackers@freebsd.org mailing list
>> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
>> To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.or=
g
>> "
>>
>



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