From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C78AAC43331 for ; Fri, 8 Nov 2019 00:04:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 76E6F21D79 for ; Fri, 8 Nov 2019 00:04:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726094AbfKHAEf (ORCPT ); Thu, 7 Nov 2019 19:04:35 -0500 Received: from cloudserver094114.home.pl ([79.96.170.134]:48860 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725940AbfKHAEe (ORCPT ); Thu, 7 Nov 2019 19:04:34 -0500 Received: from 79.184.254.83.ipv4.supernova.orange.pl (79.184.254.83) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.292) id 4b51c36d0c6d2e90; Fri, 8 Nov 2019 01:04:31 +0100 From: "Rafael J. Wysocki" To: Dmitry Torokhov Cc: "Rafael J. Wysocki" , Heikki Krogerus , Andy Shevchenko , Mika Westerberg , Linus Walleij , Ard Biesheuvel , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org Subject: Re: [PATCH v6 11/15] software node: move small properties inline when copying Date: Fri, 08 Nov 2019 01:04:31 +0100 Message-ID: <3310518.lfHdziMng4@kreacher> In-Reply-To: <20191105235656.GW57214@dtor-ws> References: <20191023200233.86616-1-dmitry.torokhov@gmail.com> <47671501.dVG71sAca0@kreacher> <20191105235656.GW57214@dtor-ws> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Wednesday, November 6, 2019 12:56:56 AM CET Dmitry Torokhov wrote: > Hi Rafael, > > On Wed, Nov 06, 2019 at 12:42:02AM +0100, Rafael J. Wysocki wrote: > > On Wednesday, October 23, 2019 10:02:29 PM CET 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. > > > > Yes, we can do that, but how much of a difference does this really make? > > Arguably not much I think, but it was pretty cheap to do. > > > > > Also, how can one distinguish between a single-value property and an inline > > array which this change? By looking at the length? > > We do not really need to distinguish between the 2. The device > properties API is typically wrap single values around arrays (i.e. it is > perfectly fine to use scalar API to fetch first element of array and use > array API to fetch a scalar). So we have property of certain type with > certain number of elements, and it can either be stored inside > property_entry structure, or outside of it. They are 2 orthogonal > concepts. > > > > > > Signed-off-by: Dmitry Torokhov > > > --- > > > drivers/base/swnode.c | 10 ++++++++++ > > > 1 file changed, 10 insertions(+) > > > > > > diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c > > > index 18a30fb3cc58..49e1108aa4b7 100644 > > > --- a/drivers/base/swnode.c > > > +++ b/drivers/base/swnode.c > > > @@ -280,6 +280,16 @@ static int property_entry_copy_data(struct property_entry *dst, > > > if (!dst->name) > > > goto out_free_data; > > > > > > + 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); > > > + dst->is_inline = true; > > > + > > > + kfree(tmp); > > > > This would have been more useful if we had been able to avoid making the > > allocation altogether. > > OK, I can do that and re-send this patch and the one with the tests. But if you do that, IMO it would be prudent to extend the definition of struct property_entry like this: struct property_entry { const char *name; size_t length; bool is_array; enum dev_prop_type type; union { union { const u8 *u8_data; const u16 *u16_data; const u32 *u32_data; const u64 *u64_data; const char * const *str; } pointer; union { u8 u8_data; u16 u16_data; u32 u32_data; u64 u64_data; const char *str; + u8 u8_buf[sizeof(u64)]; + u16 u16_buf[sizeof(u64)/sizeof(u16)]; + u32 u32_buf[sizeof(u64)/sizeof(u32)]; + char char_buf[sizeof(u64)]; } value; }; }; to make it clear that the value field is going to be used as an array in some cases. > In the mean time, can you please consider patches 12-14? I cannot find drivers/platform/x86/intel_cht_int33fe_typec.c in the mainline, so I cannot apply patch [13/15] now and I'm not sure how useful it would be to apply patches [10,12/15] without the other two.