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Date: Mon, 23 Apr 2018 20:31:15 -0400
From: "Emilio G. Cota" <cota@braap.org>
Message-ID: <20180424003115.GD8651@flamenco>
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Subject: Re: [Qemu-devel] [PATCH v2 12/17] translate-all: add
 page_collection assertions
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To: Richard Henderson <richard.henderson@linaro.org>
Cc: qemu-devel@nongnu.org, Alex =?iso-8859-1?Q?Benn=E9e?= <alex.bennee@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>

On Fri, Apr 13, 2018 at 17:42:45 -1000, Richard Henderson wrote:
> On 04/05/2018 04:13 PM, Emilio G. Cota wrote:
> > +static __thread bool page_collection_locked;
> > +
> > +void assert_page_collection_locked(bool val)
> > +{
> > +    tcg_debug_assert(page_collection_locked == val);
> > +}
> > +
> > +static inline void set_page_collection_locked(bool val)
> > +{
> > +    page_collection_locked = val;
> > +}
> > +
> 
> This seems fairly fragile to me.
> 
> (1) Do you ever do assert_page_collection_locked(true)?

No.

> You don't appear to do so, and it's somewhat confusing.

You're right. I think in testing I was using it, but now it
might make more sense to not take any arguments.

> (2) Why does do_page_entry_lock set "locked" and not page_collection_lock?

page_collection_lock calls page_entry_lock and page_trylock_add,
both of which end up calling do_page_entry_lock.

Thanks,

		Emilio