From: Andrew Morton <akpm@osdl.org>
To: Nikita Danilov <nikita@clusterfs.com>
Cc: pmarques@grupopie.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, hch@infradead.org
Subject: Re: [RFC] per thread page reservation patch
Date: Fri, 7 Jan 2005 15:43:05 -0800 [thread overview]
Message-ID: <20050107154305.790b8a51.akpm@osdl.org> (raw)
In-Reply-To: <m18y74rfqs.fsf@clusterfs.com>
Nikita Danilov <nikita@clusterfs.com> wrote:
>
> >
> > Why does the filesystem risk going oom during the rebalance anyway? Is it
> > doing atomic allocations?
>
> No, just __alloc_pages(GFP_KERNEL, 0, ...) returns NULL. When this
> happens, the only thing balancing can do is to panic.
__alloc_pages(GFP_KERNEL, ...) doesn't return NULL. It'll either succeed
or never return ;) That behaviour may change at any time of course, but it
does make me wonder why we're bothering with this at all. Maybe it's
because of the possibility of a GFP_IO failure under your feet or
something?
What happens if reiser4 simply doesn't use this code?
If we introduce this mechanism, people will end up using it all over the
place. Probably we could remove radix_tree_preload(), which is the only
similar code I can I can immediately think of.
Page reservation is not a bad thing per-se, but it does need serious
thought.
How does reiser4 end up deciding how many pages to reserve? Gross
overkill?
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next prev parent reply other threads:[~2005-01-07 23:43 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20050103011113.6f6c8f44.akpm@osdl.org>
[not found] ` <20050103114854.GA18408@infradead.org>
[not found] ` <41DC2386.9010701@namesys.com>
[not found] ` <1105019521.7074.79.camel@tribesman.namesys.com>
[not found] ` <20050107144644.GA9606@infradead.org>
2005-01-07 17:16 ` Vladimir Saveliev
2005-01-07 18:48 ` Andrew Morton
2005-01-07 20:21 ` Nikita Danilov
2005-01-07 19:05 ` Christoph Hellwig
2005-01-07 19:12 ` Christoph Hellwig
2005-01-07 19:21 ` Robert Love
2005-01-07 20:48 ` Nikita Danilov
2005-01-07 20:54 ` Christoph Hellwig
2005-01-07 21:00 ` Nikita Danilov
2005-01-07 21:07 ` Christoph Hellwig
2005-01-07 19:14 ` Paulo Marques
2005-01-07 19:32 ` Christoph Hellwig
2005-01-07 19:42 ` Andi Kleen
2005-01-07 20:55 ` Nikita Danilov
2005-01-07 21:24 ` Andrew Morton
2005-01-07 21:24 ` Andi Kleen
2005-01-07 22:12 ` Nikita Danilov
2005-01-07 23:03 ` Andrew Morton
2005-01-07 23:17 ` Nikita Danilov
2005-01-07 23:43 ` Andrew Morton [this message]
2005-01-08 12:44 ` Nikita Danilov
2005-01-08 13:43 ` Hugh Dickins
2005-01-09 11:35 ` Marcelo Tosatti
2005-01-09 18:16 ` Nikita Danilov
2005-01-25 16:39 ` reiser4 core patches: [Was: [RFC] per thread page reservation patch] Vladimir Saveliev
2005-01-27 10:37 ` Adrian Bunk
2005-01-27 11:01 ` Christoph Hellwig
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