From: Christoph Hellwig <hch@lst.de>
To: NeilBrown <neilb@suse.com>
Cc: shli@fb.com, linux-raid@vger.kernel.org
Subject: Re: [PATCH 1/2] raid5-cache: use a bio_set
Date: Mon, 14 Dec 2015 22:12:00 +0100 [thread overview]
Message-ID: <20151214211200.GA17714@lst.de> (raw)
In-Reply-To: <87bna0r0ez.fsf@notabene.neil.brown.name>
On Wed, Dec 09, 2015 at 10:22:12AM +1100, NeilBrown wrote:
> > +/*
> > + * We only need 2 bios per I/O unit to make progress, but ensure we
> > + * have a few more available to not get too tight.
> > + */
> > +#define R5L_POOL_SIZE 1024
> > +
>
> I'm really suspicious of big pool sizes.
> The memory allocated to the pool is almost never used - only where no
> other memory is available - so large pools are largely wasted.
I originally had 16 here, andd incremented it for some debugging that
stuck. I retested with 4 and that works as well. That will be included
in the next resend.
next prev parent reply other threads:[~2015-12-14 21:12 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-02 16:10 [RFC] using mempools for raid5-cache Christoph Hellwig
2015-12-02 16:10 ` [PATCH 1/2] raid5-cache: use a bio_set Christoph Hellwig
2015-12-03 5:01 ` Shaohua Li
2015-12-08 23:22 ` NeilBrown
2015-12-14 21:12 ` Christoph Hellwig [this message]
2015-12-02 16:10 ` [PATCH 2/2] raid5-cache: use a mempool for the metadata block Christoph Hellwig
2015-12-08 23:27 ` NeilBrown
2015-12-03 4:49 ` [RFC] using mempools for raid5-cache Shaohua Li
2015-12-09 0:36 ` NeilBrown
2015-12-09 1:28 ` Shaohua Li
2015-12-09 6:34 ` NeilBrown
2015-12-10 23:40 ` Shaohua Li
2015-12-11 0:09 ` NeilBrown
2015-12-11 1:10 ` Shaohua Li
2015-12-11 1:56 ` NeilBrown
2015-12-09 13:51 ` Wols Lists
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