From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH v6 11/15] software node: move small properties inline when copying Date: Thu, 7 Nov 2019 16:28:44 -0800 Message-ID: <20191108002844.GX57214@dtor-ws> References: <20191023200233.86616-1-dmitry.torokhov@gmail.com> <47671501.dVG71sAca0@kreacher> <20191105235656.GW57214@dtor-ws> <3310518.lfHdziMng4@kreacher> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <3310518.lfHdziMng4@kreacher> Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" 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 List-Id: platform-driver-x86.vger.kernel.org On Fri, Nov 08, 2019 at 01:04:31AM +0100, Rafael J. Wysocki wrote: > 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. Sorry, just sent out updated series before receiving your email. I can cook up new patch cleaning this. I think we can drop scalars and only have arrays and have initializers use _data[0] to create initial property entries. > > > 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. Hmm, drivers/platform/x86/intel_cht_int33fe_typec.c used to be drivers/platform/x86/intel_cht_int33fe.c I think. I can either regenerate against your tree instead of -next (but then there will be merge conflict) or we could postpone #13 and #14 (or #5 and #6 in v7) till after merge window. Please let me know. -- Dmitry