Re: [Intel-gfx] [PATCH v4] string-choice: add yesno(), onoff(), enableddisabled(), plural() helpers
On 24/10/2019 09.40, Rasmus Villemoes wrote: > column. Maybe your compiler doesn't do string literal merging (since the > linker does it anyway), so your .rodata.str1.1 might contain several > copies of "yes" and "no", but they shouldn't really be counted. Sorry, that's of course nonsense - the strings only appear once in the TU (inside the static inline function), so gcc must treat them all as the same object - as opposed to the case where the implementation was #define yesno(x) ((x) ? "yes" : "no") So that can't explain why you saw a smaller text segment using the OOL version. Rasmus ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH v4] string-choice: add yesno(), onoff(), enableddisabled(), plural() helpers
On 24/10/2019 00.56, Andrew Morton wrote:
> On Wed, 23 Oct 2019 16:13:08 +0300 Jani Nikula wrote:
>
>> +
>> +static inline const char *yesno(bool v)
>> +{
>> +return v ? "yes" : "no";
>> +}
>> +
>> +static inline const char *onoff(bool v)
>> +{
>> +return v ? "on" : "off";
>> +}
>> +
>> +static inline const char *enableddisabled(bool v)
>> +{
>> +return v ? "enabled" : "disabled";
>> +}
>> +
>> +static inline const char *plural(long v)
>> +{
>> +return v == 1 ? "" : "s";
>> +}
>> +
>> +#endif /* __STRING_CHOICE_H__ */
>
> These aren't very good function names. Better to create a kernel-style
> namespace such as "choice_" and then add the expected underscores:
>
> choice_yes_no()
> choice_enabled_disabled()
> choice_plural()
I think I prefer the short names (no choice_ prefix), it's rather
obvious what they do. I also asked for underscores, especially for the
enableddisabled case, but Jani didn't want to change existing callers.
But I'll keep out of the naming discussion from now on.
> Also, I worry that making these functions inline means that each .o
> file will contain its own copy of the strings
They will, in .rodata.str1.1
("yes", "no", "enabled",
> etc) if the .c file calls the relevant helper. I'm not sure if the
> linker is smart enough (yet) to fix this up.
AFAIK, that's an optimization the linker has done forever - the whole
reason the SHF_MERGE | SHF_STRINGS (the MS in readelf -S output) flags
exist (and AFAICT they have been part of the ELF spec since forever) is
so the linker can do that trick. So no, do not make them ool.
> And doing this will cause additional savings: calling a single-arg
> out-of-line function generates less .text than calling yesno(). When I
> did this:
>
> ---
> a/include/linux/string-choice.h~string-choice-add-yesno-onoff-enableddisabled-plural-helpers-fix
> +++ a/include/linux/string-choice.h
> @@ -8,10 +8,7 @@
>
> #include
>
> -static inline const char *yesno(bool v)
> -{
> - return v ? "yes" : "no";
> -}
> +const char *yesno(bool v);
>
> static inline const char *onoff(bool v)
> {
>
> The text segment of drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.o
> (78 callsites) shrunk by 118 bytes.
>
Interesting, and not at all what I see. Mind dumping rss_config_show
before/after? Even better, cxgb4_debugfs.s before/after. Here's what I get:
static inline yesno:
cbb: 49 c7 c4 00 00 00 00mov$0x0,%r12cbe:
R_X86_64_32S .rodata.str1.1+0x197
cc2: 44 89 eamov%r13d,%edx
cc5: 48 c7 c6 00 00 00 00mov$0x0,%rsicc8:
R_X86_64_32S .rodata.str1.1+0x1b7
ccc: 48 c7 c5 00 00 00 00mov$0x0,%rbpccf:
R_X86_64_32S .rodata.str1.1+0x19b
Load "yes" into %12 and "no" into %rbp (or vice versa).
cd3: 4d 89 e7mov%r12,%r15
cd6: e8 00 00 00 00 callq cdb
cd7: R_X86_64_PC32 seq_printf-0x4
cdb: 45 85 edtest %r13d,%r13d
cde: 4c 89 e2mov%r12,%rdx
ce1: 48 89 dfmov%rbx,%rdi
ce4: 48 0f 49 d5 cmovns %rbp,%rdx
ce8: 48 c7 c6 00 00 00 00mov$0x0,%rsiceb:
R_X86_64_32S .rodata.str1.1+0x1cb
cef: e8 00 00 00 00 callq cf4
cf0: R_X86_64_PC32 seq_printf-0x4
cf4: 41 f7 c5 00 00 00 40test $0x4000,%r13d
cfb: 4c 89 e2mov%r12,%rdx
cfe: 48 89 dfmov%rbx,%rdi
d01: 48 0f 44 d5 cmove %rbp,%rdx
d05: 48 c7 c6 00 00 00 00mov$0x0,%rsid08:
R_X86_64_32S .rodata.str1.1+0x1e1
d0c: e8 00 00 00 00 callq d11
d0d: R_X86_64_PC32 seq_printf-0x4
Test a bit, move "yes" into %rdx, conditionally move "no" into %rdx
instead, call seq_printf.
d11: 41 f7 c5 00 00 00 20test $0x2000,%r13d
d18: 4c 89 e2mov%r12,%rdx
d1b: 48 89 dfmov%rbx,%rdi
d1e: 48 0f 44 d5 cmove %rbp,%rdx
d22: 48 c7 c6 00 00 00 00mov$0x0,%rsid25:
R_X86_64_32S .rodata.str1.1+0x1f7
d29: e8 00 00 00 00 callq d2e
d2a: R_X86_64_PC32 seq_printf-0x4
etc. That's a marginal (i.e., after the preamble storing "yes" and "no"
in callee-saved registers) cost of six instructions/29 bytes per
seq_printf, three of which are to implement the yesno() call.
extern const char *yesno():
64e7: 48 c7 c6 00 00 00 00mov$0x0,%rsi64ea:
R_X86_64_32S .rodata.str1.1+0x8e4
64ee: 89 ea mov%ebp,%edx
64f0: 41 89 edmov%ebp,%r13d
64f3: e8 00 00 00 00 callq 64f8
64f4: R_X86_64_PC32 seq_printf-0x4
64f8: 89 ef mov
Re: [Intel-gfx] [PATCH v4] string-choice: add yesno(), onoff(), enableddisabled(), plural() helpers
On Wed, 23 Oct 2019, Andrew Morton wrote:
> On Wed, 23 Oct 2019 16:13:08 +0300 Jani Nikula wrote:
>
>> The kernel has plenty of ternary operators to choose between constant
>> strings, such as condition ? "yes" : "no", as well as value == 1 ? "" :
>> "s":
>>
>> $ git grep '? "yes" : "no"' | wc -l
>> 258
>> $ git grep '? "on" : "off"' | wc -l
>> 204
>> $ git grep '? "enabled" : "disabled"' | wc -l
>> 196
>> $ git grep '? "" : "s"' | wc -l
>> 25
>>
>> Additionally, there are some occurences of the same in reverse order,
>> split to multiple lines, or otherwise not caught by the simple grep.
>>
>> Add helpers to return the constant strings. Remove existing equivalent
>> and conflicting functions in i915, cxgb4, and USB core. Further
>> conversion can be done incrementally.
>>
>> The main goal here is to abstract recurring patterns, and slightly clean
>> up the code base by not open coding the ternary operators.
>
> Fair enough.
>
>> --- /dev/null
>> +++ b/include/linux/string-choice.h
>> @@ -0,0 +1,31 @@
>> +/* SPDX-License-Identifier: MIT */
>> +/*
>> + * Copyright © 2019 Intel Corporation
>> + */
>> +
>> +#ifndef __STRING_CHOICE_H__
>> +#define __STRING_CHOICE_H__
>> +
>> +#include
>> +
>> +static inline const char *yesno(bool v)
>> +{
>> +return v ? "yes" : "no";
>> +}
>> +
>> +static inline const char *onoff(bool v)
>> +{
>> +return v ? "on" : "off";
>> +}
>> +
>> +static inline const char *enableddisabled(bool v)
>> +{
>> +return v ? "enabled" : "disabled";
>> +}
>> +
>> +static inline const char *plural(long v)
>> +{
>> +return v == 1 ? "" : "s";
>> +}
>> +
>> +#endif /* __STRING_CHOICE_H__ */
>
> These aren't very good function names. Better to create a kernel-style
> namespace such as "choice_" and then add the expected underscores:
>
> choice_yes_no()
> choice_enabled_disabled()
> choice_plural()
I was merely using existing function names used in several drivers in
the kernel. But I can rename no problem.
Are your suggestions the names we can settle on now, or should I expect
to receive more opinions, but only after I send v5?
> (Example: note that slabinfo.c already has an "onoff()").
Under tools/ though? I did mean to address all conflicts in this patch.
> Also, I worry that making these functions inline means that each .o
> file will contain its own copy of the strings ("yes", "no", "enabled",
> etc) if the .c file calls the relevant helper. I'm not sure if the
> linker is smart enough (yet) to fix this up. If not, we will end up
> with a smaller kernel by uninlining these functions.
> lib/string-choice.c would suit.
>
> And doing this will cause additional savings: calling a single-arg
> out-of-line function generates less .text than calling yesno(). When I
> did this:
>
> ---
> a/include/linux/string-choice.h~string-choice-add-yesno-onoff-enableddisabled-plural-helpers-fix
> +++ a/include/linux/string-choice.h
> @@ -8,10 +8,7 @@
>
> #include
>
> -static inline const char *yesno(bool v)
> -{
> - return v ? "yes" : "no";
> -}
> +const char *yesno(bool v);
>
> static inline const char *onoff(bool v)
> {
>
> The text segment of drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.o
> (78 callsites) shrunk by 118 bytes.
So we've already been back and forth on that particular topic in the
history of this patch. v2 had lib/string-choice.c and no inlines [1].
In the end, starting to use functions, inline or not, will let us rework
the implementation as we see fit, without touching the callers.
Again, it's no problem to go back to lib/string-choice.c, *once* more,
and the effort is trivial, but the ping-pong is getting old.
BR,
Jani.
[1] http://lore.kernel.org/r/20190930141842.15075-1-jani.nik...@intel.com
--
Jani Nikula, Intel Open Source Graphics Center
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Re: [Intel-gfx] [PATCH v4] string-choice: add yesno(), onoff(), enableddisabled(), plural() helpers
On Wed, 2019-10-23 at 15:56 -0700, Andrew Morton wrote: > And doing this will cause additional savings: calling a single-arg > out-of-line function generates less .text than calling yesno(). I get no change in size at all with any of extern static __always_inline with either of bool or int argument. gcc 8.3, defconfig with CONFIG_CHELSIO_T4 ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH v4] string-choice: add yesno(), onoff(), enableddisabled(), plural() helpers
On Wed, 23 Oct 2019 16:13:08 +0300 Jani Nikula wrote:
> The kernel has plenty of ternary operators to choose between constant
> strings, such as condition ? "yes" : "no", as well as value == 1 ? "" :
> "s":
>
> $ git grep '? "yes" : "no"' | wc -l
> 258
> $ git grep '? "on" : "off"' | wc -l
> 204
> $ git grep '? "enabled" : "disabled"' | wc -l
> 196
> $ git grep '? "" : "s"' | wc -l
> 25
>
> Additionally, there are some occurences of the same in reverse order,
> split to multiple lines, or otherwise not caught by the simple grep.
>
> Add helpers to return the constant strings. Remove existing equivalent
> and conflicting functions in i915, cxgb4, and USB core. Further
> conversion can be done incrementally.
>
> The main goal here is to abstract recurring patterns, and slightly clean
> up the code base by not open coding the ternary operators.
Fair enough.
> --- /dev/null
> +++ b/include/linux/string-choice.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2019 Intel Corporation
> + */
> +
> +#ifndef __STRING_CHOICE_H__
> +#define __STRING_CHOICE_H__
> +
> +#include
> +
> +static inline const char *yesno(bool v)
> +{
> + return v ? "yes" : "no";
> +}
> +
> +static inline const char *onoff(bool v)
> +{
> + return v ? "on" : "off";
> +}
> +
> +static inline const char *enableddisabled(bool v)
> +{
> + return v ? "enabled" : "disabled";
> +}
> +
> +static inline const char *plural(long v)
> +{
> + return v == 1 ? "" : "s";
> +}
> +
> +#endif /* __STRING_CHOICE_H__ */
These aren't very good function names. Better to create a kernel-style
namespace such as "choice_" and then add the expected underscores:
choice_yes_no()
choice_enabled_disabled()
choice_plural()
(Example: note that slabinfo.c already has an "onoff()").
Also, I worry that making these functions inline means that each .o
file will contain its own copy of the strings ("yes", "no", "enabled",
etc) if the .c file calls the relevant helper. I'm not sure if the
linker is smart enough (yet) to fix this up. If not, we will end up
with a smaller kernel by uninlining these functions.
lib/string-choice.c would suit.
And doing this will cause additional savings: calling a single-arg
out-of-line function generates less .text than calling yesno(). When I
did this:
---
a/include/linux/string-choice.h~string-choice-add-yesno-onoff-enableddisabled-plural-helpers-fix
+++ a/include/linux/string-choice.h
@@ -8,10 +8,7 @@
#include
-static inline const char *yesno(bool v)
-{
- return v ? "yes" : "no";
-}
+const char *yesno(bool v);
static inline const char *onoff(bool v)
{
The text segment of drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.o
(78 callsites) shrunk by 118 bytes.
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Re: [Intel-gfx] [PATCH v4] string-choice: add yesno(), onoff(), enableddisabled(), plural() helpers
On Wed, 23 Oct 2019, Rasmus Villemoes wrote: > On 23/10/2019 15.13, Jani Nikula wrote: >> The kernel has plenty of ternary operators to choose between constant >> strings, such as condition ? "yes" : "no", as well as value == 1 ? "" : >> "s": >> >> >> v4: Massaged commit message about space savings to make it less fluffy >> based on Rasmus' feedback. > > Thanks, it looks good to me. FWIW, > > Acked-by: Rasmus Villemoes Thanks. I think the question is, which tree to apply this to, who's going to pick it up? I'm fine with any route. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH v4] string-choice: add yesno(), onoff(), enableddisabled(), plural() helpers
On 23/10/2019 15.13, Jani Nikula wrote: > The kernel has plenty of ternary operators to choose between constant > strings, such as condition ? "yes" : "no", as well as value == 1 ? "" : > "s": > > > v4: Massaged commit message about space savings to make it less fluffy > based on Rasmus' feedback. Thanks, it looks good to me. FWIW, Acked-by: Rasmus Villemoes ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
[Intel-gfx] [PATCH v4] string-choice: add yesno(), onoff(), enableddisabled(), plural() helpers
The kernel has plenty of ternary operators to choose between constant
strings, such as condition ? "yes" : "no", as well as value == 1 ? "" :
"s":
$ git grep '? "yes" : "no"' | wc -l
258
$ git grep '? "on" : "off"' | wc -l
204
$ git grep '? "enabled" : "disabled"' | wc -l
196
$ git grep '? "" : "s"' | wc -l
25
Additionally, there are some occurences of the same in reverse order,
split to multiple lines, or otherwise not caught by the simple grep.
Add helpers to return the constant strings. Remove existing equivalent
and conflicting functions in i915, cxgb4, and USB core. Further
conversion can be done incrementally.
The main goal here is to abstract recurring patterns, and slightly clean
up the code base by not open coding the ternary operators.
Cc: Joonas Lahtinen
Cc: Rodrigo Vivi
Cc: intel-gfx@lists.freedesktop.org
Cc: Vishal Kulkarni
Cc: net...@vger.kernel.org
Cc: Greg Kroah-Hartman
Cc: linux-...@vger.kernel.org
Cc: Andrew Morton
Cc: linux-ker...@vger.kernel.org
Cc: Julia Lawall
Cc: Rasmus Villemoes
Reviewed-by: Greg Kroah-Hartman
Signed-off-by: Jani Nikula
---
v2: add string-choice.[ch] to not clutter kernel.h and to actually save
space on string constants.
v3: back to static inlines based on Rasmus' feedback
v4: Massaged commit message about space savings to make it less fluffy
based on Rasmus' feedback.
Example of further cleanup possibilities are at [1], to be done
incrementally afterwards.
[1] http://lore.kernel.org/r/20190903133731.2094-2-jani.nik...@intel.com
---
drivers/gpu/drm/i915/i915_utils.h | 16 +-
.../ethernet/chelsio/cxgb4/cxgb4_debugfs.c| 12 +--
drivers/usb/core/config.c | 6 +---
drivers/usb/core/generic.c| 6 +---
include/linux/string-choice.h | 31 +++
5 files changed, 35 insertions(+), 36 deletions(-)
create mode 100644 include/linux/string-choice.h
diff --git a/drivers/gpu/drm/i915/i915_utils.h
b/drivers/gpu/drm/i915/i915_utils.h
index 562f756da421..794f02a90efe 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -28,6 +28,7 @@
#include
#include
#include
+#include
#include
#include
@@ -395,21 +396,6 @@ wait_remaining_ms_from_jiffies(unsigned long
timestamp_jiffies, int to_wait_ms)
#define MBps(x) KBps(1000 * (x))
#define GBps(x) ((u64)1000 * MBps((x)))
-static inline const char *yesno(bool v)
-{
- return v ? "yes" : "no";
-}
-
-static inline const char *onoff(bool v)
-{
- return v ? "on" : "off";
-}
-
-static inline const char *enableddisabled(bool v)
-{
- return v ? "enabled" : "disabled";
-}
-
static inline void add_taint_for_CI(unsigned int taint)
{
/*
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
index ae6a47dd7dc9..d9123dae1d00 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
@@ -35,6 +35,7 @@
#include
#include
#include
+#include
#include
#include
@@ -2023,17 +2024,6 @@ static const struct file_operations rss_debugfs_fops = {
/* RSS Configuration.
*/
-/* Small utility function to return the strings "yes" or "no" if the supplied
- * argument is non-zero.
- */
-static const char *yesno(int x)
-{
- static const char *yes = "yes";
- static const char *no = "no";
-
- return x ? yes : no;
-}
-
static int rss_config_show(struct seq_file *seq, void *v)
{
struct adapter *adapter = seq->private;
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 151a74a54386..52cee9067eb4 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -10,6 +10,7 @@
#include
#include
#include
+#include
#include
#include "usb.h"
@@ -19,11 +20,6 @@
#define USB_MAXCONFIG 8 /* Arbitrary limit */
-static inline const char *plural(int n)
-{
- return (n == 1 ? "" : "s");
-}
-
static int find_next_descriptor(unsigned char *buffer, int size,
int dt1, int dt2, int *num_skipped)
{
diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c
index 38f8b3e31762..a784a09794d6 100644
--- a/drivers/usb/core/generic.c
+++ b/drivers/usb/core/generic.c
@@ -21,14 +21,10 @@
#include
#include
+#include
#include
#include "usb.h"
-static inline const char *plural(int n)
-{
- return (n == 1 ? "" : "s");
-}
-
static int is_rndis(struct usb_interface_descriptor *desc)
{
return desc->bInterfaceClass == USB_CLASS_COMM
diff --git a/include/linux/string-choice.h b/include/linux/string-choice.h
new file mode 100644
index ..320b598bd8f0
--- /dev/null
+++ b/include/linux/string-choice.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2019 Intel Corporation
+ */
+
+#ifndef __STRING_CHOICE_H__
+#define __STRING_CHOICE_H__
+
+#include
+
+static inline const char *yesno(bool v)
+{
+
