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From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
	platform-driver-x86@vger.kernel.org
Subject: Re: [PATCH v5 11/14] software node: move small properties inline when copying
Date: Tue, 15 Oct 2019 11:25:53 -0700
Message-ID: <20191015182553.GG105649@dtor-ws> (raw)
In-Reply-To: <20191015122028.GI32742@smile.fi.intel.com>

On Tue, Oct 15, 2019 at 03:20:28PM +0300, Andy Shevchenko wrote:
> On Fri, Oct 11, 2019 at 04:07:18PM -0700, Dmitry Torokhov wrote:
> > When copying/duplicating set of properties, move smaller properties that
> > were stored separately directly inside property entry structures. We can
> > move:
> > 
> > - up to 8 bytes from U8 arrays
> > - up to 4 words
> > - up to 2 double words
> > - one U64 value
> > - one or 2 strings.
> 
> Can you show where you extract such values?

the "value" union's largest member is u64, which is 8 bytes. Strings are
pointers, so on 32-bit arches you can stuff 2 pointers into 8 bytes,
while on 64-bits you have space for only one.

> 
> > +	if (!dst->is_inline && dst->length <= sizeof(dst->value)) {
> > +		/* We have an opportunity to move the data inline */
> > +		const void *tmp = dst->pointer;
> > +
> 
> > +		memcpy(&dst->value, tmp, dst->length);
> 
> ...because this is strange trick.

Not sure what is so strange about it. You just take data that is stored
separately and move it into the structure, provided that it is not too
big (i.e. it does not exceed sizeof(value union) size).

> 
> > +		dst->is_inline = true;
> > +
> > +		kfree(tmp);
> > +	}
> 

Thanks.

-- 
Dmitry

  reply index

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-11 23:07 [PATCH v5 00/14] software node: add support for reference properties Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 01/14] software node: remove DEV_PROP_MAX Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 02/14] software node: introduce PROPERTY_ENTRY_ARRAY_XXX_LEN() Dmitry Torokhov
2019-10-15 12:02   ` Andy Shevchenko
2019-10-11 23:07 ` [PATCH v5 03/14] efi/apple-properties: use PROPERTY_ENTRY_U8_ARRAY_LEN Dmitry Torokhov
2019-10-15 12:01   ` Andy Shevchenko
2019-10-15 18:02     ` Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 04/14] software node: mark internal macros with double underscores Dmitry Torokhov
2019-10-15 12:03   ` Andy Shevchenko
2019-10-15 18:09     ` Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 05/14] software node: clean up property_copy_string_array() Dmitry Torokhov
2019-10-15 12:07   ` Andy Shevchenko
2019-10-15 18:12     ` Dmitry Torokhov
2019-10-16  7:53       ` Andy Shevchenko
2019-10-16 17:00         ` Dmitry Torokhov
2019-10-17  7:02           ` Andy Shevchenko
2019-10-11 23:07 ` [PATCH v5 06/14] software node: get rid of property_set_pointer() Dmitry Torokhov
2019-10-15 12:09   ` Andy Shevchenko
2019-10-15 18:14     ` Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 07/14] software node: remove property_entry_read_uNN_array functions Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 08/14] software node: unify PROPERTY_ENTRY_XXX macros Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 09/14] software node: simplify property_entry_read_string_array() Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 10/14] software node: rename is_array to is_inline Dmitry Torokhov
2019-10-14  7:37   ` Andy Shevchenko
2019-10-15 18:22     ` Dmitry Torokhov
2019-10-16  7:59       ` Andy Shevchenko
2019-10-16 16:54         ` Dmitry Torokhov
2019-10-17  7:16           ` Andy Shevchenko
2019-10-17 16:00             ` Dmitry Torokhov
2019-10-17 16:02   ` Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 11/14] software node: move small properties inline when copying Dmitry Torokhov
2019-10-15 12:20   ` Andy Shevchenko
2019-10-15 18:25     ` Dmitry Torokhov [this message]
2019-10-16  7:48       ` Andy Shevchenko
2019-10-16 16:01         ` Dmitry Torokhov
2019-10-16 16:18           ` Andy Shevchenko
2019-10-16 16:23             ` Andy Shevchenko
2019-10-16 16:44               ` Dmitry Torokhov
2019-10-17 16:04   ` Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 12/14] software node: implement reference properties Dmitry Torokhov
2019-10-11 23:07 ` [PATCH v5 13/14] platform/x86: intel_cht_int33fe: use inline " Dmitry Torokhov
2019-10-16  8:01   ` Andy Shevchenko
2019-10-11 23:07 ` [PATCH v5 14/14] software node: remove separate handling of references Dmitry Torokhov
2019-10-14  7:38 ` [PATCH v5 00/14] software node: add support for reference properties Andy Shevchenko
2019-10-14 23:57   ` Dmitry Torokhov
2019-10-16  8:02     ` Andy Shevchenko

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