linux-kernel - Re: [PATCH v9 03/18] kunit: test: add string_stream a std::stream like string builder

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Message-Id: <20190715220407.0030420665@mail.kernel.org>
Date:   Mon, 15 Jul 2019 15:04:06 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Brendan Higgins <brendanhiggins@...gle.com>
Cc:     Frank Rowand <frowand.list@...il.com>,
        Greg KH <gregkh@...uxfoundation.org>,
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Subject: Re: [PATCH v9 03/18] kunit: test: add string_stream a std::stream like string builder

Quoting Brendan Higgins (2019-07-15 14:11:50)
> On Mon, Jul 15, 2019 at 1:43 PM Stephen Boyd <sboyd@...nel.org> wrote:
> >
> > I also wonder if it would be better to just have a big slop buffer of a
> > 4K page or something so that we almost never have to allocate anything
> > with a string_stream and we can just rely on a reader consuming data
> > while writers are writing. That might work out better, but I don't quite
> > understand the use case for the string stream.
> 
> That makes sense, but might that also waste memory since we will
> almost never need that much memory?

Why do we care? These are unit tests. Having allocations in here makes
things more complicated, whereas it would be simpler to have a pointer
and a spinlock operating on a chunk of memory that gets flushed out
periodically.