From: Jakub Kicinski <kuba@kernel.org>
To: Joe Perches <joe@perches.com>
Cc: netdev <netdev@vger.kernel.org>,
Johannes Berg <johannes.berg@intel.com>,
Jonathan Toppins <jtoppins@redhat.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] netlink: NL_SET_ERR_MSG - remove local static array
Date: Tue, 10 Aug 2021 13:30:58 -0700 [thread overview]
Message-ID: <20210810133058.0c7f0736@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <1f99c69f4e640accaf7459065e6625e73ec0f8d4.camel@perches.com>
On Mon, 09 Aug 2021 10:04:00 -0700 Joe Perches wrote:
> The want was to have some separate object section for netlink messages
> so all netlink messages could be specifically listed by some tool but
> the effect is duplicating static const char arrays in the object code.
>
> It seems unused presently so change the macro to avoid the local static
> declarations until such time as these actually are wanted and used.
>
> This reduces object size ~8KB in an x86-64 defconfig without modules.
>
> $ size vmlinux.o*
> text data bss dec hex filename
> 20110471 3460344 741760 24312575 172faff vmlinux.o.new
> 20119444 3460344 741760 24321548 1731e0c vmlinux.o.old
>
> Signed-off-by: Joe Perches <joe@perches.com>
I guess we can bring it back when it's needed.
> diff --git a/include/linux/netlink.h b/include/linux/netlink.h
> index 61b1c7fcc401e..4bb32ae134aa8 100644
> --- a/include/linux/netlink.h
> +++ b/include/linux/netlink.h
> @@ -89,13 +89,12 @@ struct netlink_ext_ack {
> * to the lack of an output buffer.)
> */
> #define NL_SET_ERR_MSG(extack, msg) do { \
> - static const char __msg[] = msg; \
> struct netlink_ext_ack *__extack = (extack); \
> \
> - do_trace_netlink_extack(__msg); \
> + do_trace_netlink_extack(msg); \
> \
> if (__extack) \
> - __extack->_msg = __msg; \
> + __extack->_msg = msg; \
> } while (0)
But you've made us evaluate msg multiple times now.
Given extack is carefully evaluated only once this stands out.
> #define NL_SET_ERR_MSG_MOD(extack, msg) \
> @@ -111,13 +110,12 @@ struct netlink_ext_ack {
> #define NL_SET_BAD_ATTR(extack, attr) NL_SET_BAD_ATTR_POLICY(extack, attr, NULL)
>
> #define NL_SET_ERR_MSG_ATTR_POL(extack, attr, pol, msg) do { \
> - static const char __msg[] = msg; \
> struct netlink_ext_ack *__extack = (extack); \
> \
> - do_trace_netlink_extack(__msg); \
> + do_trace_netlink_extack(msg); \
> \
> if (__extack) { \
> - __extack->_msg = __msg; \
> + __extack->_msg = msg; \
> __extack->bad_attr = (attr); \
> __extack->policy = (pol); \
Same here.
next prev parent reply other threads:[~2021-08-10 20:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-09 17:04 [PATCH] netlink: NL_SET_ERR_MSG - remove local static array Joe Perches
2021-08-09 22:30 ` Jonathan Toppins
2021-08-10 20:30 ` Jakub Kicinski [this message]
2021-08-11 4:07 ` Joe Perches
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