Date: Mon, 20 Jun 2005 10:07:57 -0700 From: "David O'Brien" <obrien@FreeBSD.ORG> To: Dmitry Pryanishnikov <dmitry@atlantis.dp.ua> Cc: cvs-src@FreeBSD.ORG, src-committers@FreeBSD.ORG Subject: Re: cvs commit: src/sys/vm uma_int.h Message-ID: <20050620170757.GA40288@dragon.NUXI.org> In-Reply-To: <20050620124020.H21125@atlantis.atlantis.dp.ua> References: <20050620124020.H21125@atlantis.atlantis.dp.ua>
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On Mon, Jun 20, 2005 at 12:45:37PM +0300, Dmitry Pryanishnikov wrote:
>
> Hello!
>
> >Date: Sun, 19 Jun 2005 11:11:00 +0300
> >From: Giorgos Keramidas <keramida@ceid.upatras.gr>
> >To: Wilko Bulte <wb@freebie.xs4all.nl>
> >Cc: src-committers@FreeBSD.ORG, Alan Cox <alc@FreeBSD.ORG>,
> > cvs-src@FreeBSD.ORG, Alan Cox <alc@cs.rice.edu>,
> > cvs-all@FreeBSD.ORG, David O'Brien <obrien@FreeBSD.ORG>
> >
> >On 2005-06-17 21:24, Wilko Bulte <wb@freebie.xs4all.nl> wrote:
> >> On Fri, Jun 17, 2005 at 12:46:58PM -0500, Alan Cox wrote..
> >> >
> >> > I recall that 42 was the minimum to fix Eric's panic. I chose 48 so
> >>
> >Of course it should be 42...
> >
> >So, who's going to commit this?
> >
> >%
> >% -#define UMA_BOOT_PAGES 48 /* Pages allocated for
> >startup % +#define UMA_BOOT_PAGES 42 /* DON'T PANIC */
>
> Is it possible to tune this (or ideally, autotune) from the loader (or
> during the initialization of the kernel itself)?
I'm not sure what advantage there is in allowing this to be tuned from
the loader. What we need is to have the kernel itself auto-tune, or we
need a much better failure mode. We should have failed much more
gracefully than panics that seemed to have no rhyme or reason as to the
reason. Meaning the "smoking gun" commit wasn't the same for everyone
that hit the panic, nor was the back trace seemingly related to the "bad"
commit.
It looks like there was an attempt at a better failure mode:
sys/vm/uma_core.c:911: panic("UMA: Increase UMA_BOOT_PAGES");
but it wasn't extensive enough and was being triggered in this case.
--
-- David (obrien@FreeBSD.org)
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