Re: [PATCH 14/17] bcache: back to cache all readahead I/Os

Michael Lyle
2020-01-24T16:48:23Z

Hi Coly---

Thank you for holding the patch. I'm sorry for the late review (I was
travelling).

(We sure have a lot of settings and a lot of code dealing with them
all, which is unfortunate... but workloads / hardware used with bcache
are so varied).

Mike

On Thu, Jan 23, 2020 at 9:28 AM Coly Li <colyli@suse.de> wrote:
>
> On 2020/1/24 1:19 上午, Michael Lyle wrote:
> > Hi Coly and Jens--
> >
> > One concern I have with this is that it's going to wear out
> > limited-lifetime SSDs a -lot- faster. Was any thought given to making
> > this a tunable instead of just changing the behavior? Even if we have
> > an anecdote or two that it seems to have increased performance for
> > some workloads, I don't expect it will have increased performance in
> > general and it may even be costly for some workloads (it all comes
> > down to what is more useful in the cache-- somewhat-recently readahead
> > data, or the data that it is displacing).
>
> Hi Mike,
>
> Copied. This is good suggestion, I will do it after I back from Lunar
> New Year vacation, and submit it with other tested patches in following
> v5.6-rc versions.
>
> Thanks.
>
> Coly Li
>
> [snipped]
>
> --
>
> Coly Li