Re: [PATCH net-next 2/2] bonding: combine netlink and console error messages

From: Joe Perches
Date: Mon Aug 09 2021 - 01:05:43 EST


On Sun, 2021-08-08 at 22:07 -0400, Jonathan Toppins wrote:
> On 8/8/21 6:02 AM, Joe Perches wrote:
> > On Sat, 2021-08-07 at 17:54 -0400, Jonathan Toppins wrote:
> > > On 8/6/21 11:52 PM, Joe Perches wrote:
> > > > On Fri, 2021-08-06 at 23:30 -0400, Jonathan Toppins wrote:
> > > > > There seems to be no reason to have different error messages between
> > > > > netlink and printk. It also cleans up the function slightly.
> > > > []
> > > > > diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> > > > []
> > > > > +#define BOND_NL_ERR(bond_dev, extack, errmsg) do { \
> > > > > + NL_SET_ERR_MSG(extack, errmsg); \
> > > > > + netdev_err(bond_dev, "Error: " errmsg "\n"); \
> > > > > +} while (0)
> > > > > +
> > > > > +#define SLAVE_NL_ERR(bond_dev, slave_dev, extack, errmsg) do { \
> > > > > + NL_SET_ERR_MSG(extack, errmsg); \
> > > > > + slave_err(bond_dev, slave_dev, "Error: " errmsg "\n"); \
> > > > > +} while (0)
> > > >
> > > > If you are doing this, it's probably smaller object code to use
> > > > "%s", errmsg
> > > > as the errmsg string can be reused
> > > >
> > > > #define BOND_NL_ERR(bond_dev, extack, errmsg) \
> > > > do { \
> > > > NL_SET_ERR_MSG(extack, errmsg); \
> > > > netdev_err(bond_dev, "Error: %s\n", errmsg); \
> > > > } while (0)
> > > >
> > > > #define SLAVE_NL_ERR(bond_dev, slave_dev, extack, errmsg) \
> > > > do { \
> > > > NL_SET_ERR_MSG(extack, errmsg); \
> > > > slave_err(bond_dev, slave_dev, "Error: %s\n", errmsg); \
> > > > } while (0)
> > > >
> > > >
> > >
> > > I like the thought and would agree if not for how NL_SET_ERR_MSG is
> > > coded. Unfortunately it does not appear as though doing the above change
> > > actually generates smaller object code. Maybe I have incorrectly
> > > interpreted something?
> >
> > No, it's because you are compiling allyesconfig or equivalent.
> > Try defconfig with bonding.
> >
> >
>
> $ git clean -dxf
> $ git log -1 -p
> commit 8985f8d3fa38bca5f5384f9210ed735d58fd94f2 (HEAD ->
> upstream-bonding-cleanup)
> Author: Jonathan Toppins <jtoppins@xxxxxxxxxx>
> Date: Sun Aug 8 21:45:14 2021 -0400
>
>      object code optimization
>
> diff --git a/drivers/net/bonding/bond_main.c
> b/drivers/net/bonding/bond_main.c
> index 46b95175690b..e2903ae7cdab 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -1714,12 +1714,12 @@ void bond_lower_state_changed(struct slave *slave)
>
>   #define BOND_NL_ERR(bond_dev, extack, errmsg) do { \
>          NL_SET_ERR_MSG(extack, errmsg); \
> - netdev_err(bond_dev, "Error: " errmsg "\n"); \
> + netdev_err(bond_dev, "Error: %s\n", errmsg); \
>   } while (0)
>
>   #define SLAVE_NL_ERR(bond_dev, slave_dev, extack, errmsg) do { \
>          NL_SET_ERR_MSG(extack, errmsg); \
> - slave_err(bond_dev, slave_dev, "Error: " errmsg "\n"); \
> + slave_err(bond_dev, slave_dev, "Error: %s\n", errmsg); \
>   } while (0)
>
>   /* enslave device <slave> to bond device <master> */
> $ git log --oneline -2
> 8985f8d3fa38 (HEAD -> upstream-bonding-cleanup) object code optimization
> e326bf8fd30f bonding: combine netlink and console error messages
> $ make defconfig
>    HOSTCC scripts/basic/fixdep
> [...]
> *** Default configuration is based on 'x86_64_defconfig'
> #
> # configuration written to .config
> #
> $ grep "BONDING" .config
> # CONFIG_BONDING is not set
> $ make menuconfig
>    UPD scripts/kconfig/mconf-cfg
> [...]
> configuration written to .config
>
> *** End of the configuration.
> *** Execute 'make' to start the build or try 'make help'.
>
> $ grep "BONDING" .config
> CONFIG_BONDING=m
> $ git rebase -i --exec "make drivers/net/bonding/bond_main.o; ls -l
> drivers/net/bonding/bond_main.o" HEAD^^
> Executing: make drivers/net/bonding/bond_main.o; ls -l
> drivers/net/bonding/bond_main.o
>    SYNC include/config/auto.conf.cmd
> [...]
>    CC /home/jtoppins/projects/linux-rhel7/tools/objtool/librbtree.o
>    LD /home/jtoppins/projects/linux-rhel7/tools/objtool/objtool-in.o
>    LINK /home/jtoppins/projects/linux-rhel7/tools/objtool/objtool
>    CC [M] drivers/net/bonding/bond_main.o
> -rw-r--r--. 1 jtoppins jtoppins 131800 Aug 8 21:47
> drivers/net/bonding/bond_main.o
> Executing: make drivers/net/bonding/bond_main.o; ls -l
> drivers/net/bonding/bond_main.o
>    CALL scripts/checksyscalls.sh
>    CALL scripts/atomic/check-atomics.sh
>    DESCEND objtool
>    CC [M] drivers/net/bonding/bond_main.o
> -rw-r--r--. 1 jtoppins jtoppins 131928 Aug 8 21:47

Your size is significantly different than mine (x86-64 defconfig w/ bonding)

$ gcc --version
gcc (Ubuntu 10.3.0-1ubuntu1) 10.3.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Original:

$ git log -1
commit 7999516e20bd9bb5d1f7351cbd05ca529a3a8d60 (HEAD, tag: next-20210806, origin/master, origin/HEAD)
Author: Mark Brown <broonie@xxxxxxxxxx>
Date: Fri Aug 6 17:52:53 2021 +0100

Add linux-next specific files for 20210806

Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>

$ size drivers/net/bonding/built-in.a -t
text data bss dec hex filename
59630 399 460 60489 ec49 drivers/net/bonding/bond_main.o (ex drivers/net/bonding/built-in.a)
16790 14 2 16806 41a6 drivers/net/bonding/bond_3ad.o (ex drivers/net/bonding/built-in.a)
17101 50 0 17151 42ff drivers/net/bonding/bond_alb.o (ex drivers/net/bonding/built-in.a)
7116 1516 0 8632 21b8 drivers/net/bonding/bond_sysfs.o (ex drivers/net/bonding/built-in.a)
1411 72 0 1483 5cb drivers/net/bonding/bond_sysfs_slave.o (ex drivers/net/bonding/built-in.a)
165 0 0 165 a5 drivers/net/bonding/bond_debugfs.o (ex drivers/net/bonding/built-in.a)
6971 232 0 7203 1c23 drivers/net/bonding/bond_netlink.o (ex drivers/net/bonding/built-in.a)
15889 74 0 15963 3e5b drivers/net/bonding/bond_options.o (ex drivers/net/bonding/built-in.a)
4769 0 0 4769 12a1 drivers/net/bonding/bond_procfs.o (ex drivers/net/bonding/built-in.a)
129842 2357 462 132661 20635 (TOTALS)

Then with your 2 patches:

$ size -t drivers/net/bonding/built-in.a
text data bss dec hex filename
59590 399 460 60449 ec21 drivers/net/bonding/bond_main.o (ex drivers/net/bonding/built-in.a)
16790 14 2 16806 41a6 drivers/net/bonding/bond_3ad.o (ex drivers/net/bonding/built-in.a)
17101 50 0 17151 42ff drivers/net/bonding/bond_alb.o (ex drivers/net/bonding/built-in.a)
7116 1516 0 8632 21b8 drivers/net/bonding/bond_sysfs.o (ex drivers/net/bonding/built-in.a)
1411 72 0 1483 5cb drivers/net/bonding/bond_sysfs_slave.o (ex drivers/net/bonding/built-in.a)
165 0 0 165 a5 drivers/net/bonding/bond_debugfs.o (ex drivers/net/bonding/built-in.a)
6971 232 0 7203 1c23 drivers/net/bonding/bond_netlink.o (ex drivers/net/bonding/built-in.a)
15889 74 0 15963 3e5b drivers/net/bonding/bond_options.o (ex drivers/net/bonding/built-in.a)
4769 0 0 4769 12a1 drivers/net/bonding/bond_procfs.o (ex drivers/net/bonding/built-in.a)
129802 2357 462 132621 2060d (TOTALS)

Then with my suggestion:

$ size -t drivers/net/bonding/built-in.a
text data bss dec hex filename
59561 399 460 60420 ec04 drivers/net/bonding/bond_main.o (ex drivers/net/bonding/built-in.a)
16790 14 2 16806 41a6 drivers/net/bonding/bond_3ad.o (ex drivers/net/bonding/built-in.a)
17101 50 0 17151 42ff drivers/net/bonding/bond_alb.o (ex drivers/net/bonding/built-in.a)
7116 1516 0 8632 21b8 drivers/net/bonding/bond_sysfs.o (ex drivers/net/bonding/built-in.a)
1411 72 0 1483 5cb drivers/net/bonding/bond_sysfs_slave.o (ex drivers/net/bonding/built-in.a)
165 0 0 165 a5 drivers/net/bonding/bond_debugfs.o (ex drivers/net/bonding/built-in.a)
6971 232 0 7203 1c23 drivers/net/bonding/bond_netlink.o (ex drivers/net/bonding/built-in.a)
15889 74 0 15963 3e5b drivers/net/bonding/bond_options.o (ex drivers/net/bonding/built-in.a)
4769 0 0 4769 12a1 drivers/net/bonding/bond_procfs.o (ex drivers/net/bonding/built-in.a)
129773 2357 462 132592 205f0 (TOTALS)

cheers, Joe