From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: Matthias Maennich <maennich@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Cc: Android Kernel" <kernel-team@android.com>,
Jessica Yu <jeyu@kernel.org>, Martijn Coenen <maco@android.com>,
Lucas De Marchi <lucas.de.marchi@gmail.com>,
Shaun Ruffell <sruffell@sruffell.net>,
Will Deacon <will@kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
linux-modules <linux-modules@vger.kernel.org>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: Re: [PATCH 4/4] export: avoid code duplication in include/linux/export.h
Date: Sat, 12 Oct 2019 13:25:32 +0900 [thread overview]
Message-ID: <CAK7LNASvQd8C4UE3Zm9tsSH48w3QKwskyTKn2P8tegBMrV0_ww@mail.gmail.com> (raw)
In-Reply-To: <20191011154311.GA192647@google.com>
On Sat, Oct 12, 2019 at 12:43 AM Matthias Maennich <maennich@google.com> wrote:
>
> On Fri, Oct 11, 2019 at 05:31:27PM +0200, Greg Kroah-Hartman wrote:
> >On Thu, Oct 10, 2019 at 04:14:43PM +0100, Matthias Maennich wrote:
> >> Now that the namespace value is not part of the __ksymtab entry name
> >> anymore, we can simplify the implementation of EXPORT_SYMBOL*. By
> >> allowing the empty string "" to represent 'no namespace', we can unify
> >> the implementation and drop a lot redundant code. That increases
> >> readability and maintainability.
> >>
> >> As Masahiro pointed out earlier,
> >> "The drawback of this change is, it grows the code size. When the symbol
> >> has no namespace, sym->namespace was previously NULL, but it is now am
> >> empty string "". So, it increases 1 byte for every no namespace
> >> EXPORT_SYMBOL. A typical kernel configuration has 10K exported symbols,
> >> so it increases 10KB in rough estimation."
> >
> >10Kb of non-swapable memory isn't good. But if you care about that, you
> >can get it back with the option to compile away any non-used symbols,
> >and that shouldn't be affected by this change, right?
>
> Rasmus suggested to put the 'aMS' flags on the __ksymtab_strings section
> to mitigate this:
> https://lore.kernel.org/lkml/f2e28d6b-77c5-5fe2-0bc4-b24955de9954@rasmusvillemoes.dk/
>
> I was not yet able to properly test this, so I did not include it in
> this series. As I said in the cover letter, this 4th patch might be
> optional for 5.4. So, we could defer it to a later time when we have
> addressed that properly.
This looks the same as my patch, though.
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2019-10-12 4:26 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-10 15:14 [PATCH 0/4] export/modpost: avoid renaming __ksymtab entries for symbol namespaces Matthias Maennich
2019-10-10 15:14 ` [PATCH 1/4] modpost: delegate updating namespaces to separate function Matthias Maennich
2019-10-11 14:24 ` Will Deacon
2019-10-11 15:32 ` Greg Kroah-Hartman
2019-10-12 3:19 ` Masahiro Yamada
2019-10-10 15:14 ` [PATCH 2/4] modpost: make updating the symbol namespace explict Matthias Maennich
2019-10-11 14:24 ` Will Deacon
2019-10-11 15:33 ` Greg Kroah-Hartman
2019-10-12 3:22 ` Masahiro Yamada
2019-10-10 15:14 ` [PATCH 3/4] symbol namespaces: revert to previous __ksymtab name scheme Matthias Maennich
2019-10-11 14:24 ` Will Deacon
2019-10-11 15:33 ` Greg Kroah-Hartman
2019-10-12 3:35 ` Masahiro Yamada
2019-10-10 15:14 ` [PATCH 4/4] export: avoid code duplication in include/linux/export.h Matthias Maennich
2019-10-11 15:31 ` Greg Kroah-Hartman
2019-10-11 15:43 ` Matthias Maennich
2019-10-12 4:25 ` Masahiro Yamada [this message]
2019-10-18 9:31 ` [PATCH v2 0/4] export/modpost: avoid renaming __ksymtab entries for symbol namespaces Matthias Maennich
2019-10-18 9:31 ` [PATCH v2 1/4] modpost: delegate updating namespaces to separate function Matthias Maennich
2019-10-18 9:31 ` [PATCH v2 2/4] modpost: make updating the symbol namespace explicit Matthias Maennich
2019-10-18 9:31 ` [PATCH v2 3/4] symbol namespaces: revert to previous __ksymtab name scheme Matthias Maennich
2019-10-18 9:31 ` [PATCH v2 4/4] export: avoid code duplication in include/linux/export.h Matthias Maennich
2019-10-21 13:31 ` [PATCH v2 0/4] export/modpost: avoid renaming __ksymtab entries for symbol namespaces Jessica Yu
2019-10-23 12:22 ` Luis Chamberlain
2019-10-24 9:35 ` Matthias Maennich
2019-10-24 10:24 ` Luis Chamberlain
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAK7LNASvQd8C4UE3Zm9tsSH48w3QKwskyTKn2P8tegBMrV0_ww@mail.gmail.com \
--to=yamada.masahiro@socionext.com \
--cc=gregkh@linuxfoundation.org \
--cc=jeyu@kernel.org \
--cc=kernel-team@android.com \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-modules@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=lucas.de.marchi@gmail.com \
--cc=maco@android.com \
--cc=maennich@google.com \
--cc=sruffell@sruffell.net \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).