From: Jakub Jelinek <jakub@redhat.com>
To: linux-kernel@vger.kernel.org
Subject: Why is get_current() not const function?
Date: Thu, 13 Mar 2003 06:19:26 -0500 [thread overview]
Message-ID: <20030313061926.S3910@devserv.devel.redhat.com> (raw)
Hi!
E.g. on x86-64,
NEW_AUX_ENT(AT_UID, (elf_addr_t) current->uid);
NEW_AUX_ENT(AT_EUID, (elf_addr_t) current->euid);
NEW_AUX_ENT(AT_GID, (elf_addr_t) current->gid);
NEW_AUX_ENT(AT_EGID, (elf_addr_t) current->egid);
results in 4 movq %gs:0,%rax instructions while one is completely
enough.
Anyone remembers why get_current function (on arches which define
current to get_current()) is not const and why on x86-64
the movq %%gs:0, %0 inline asm is volatile with "memory" clobber?
AFAIK current ought to be constant in any function with the exception of
schedule.
If the reason is kernel/sched.c, then IMHO it is certainly
worth making get_current const everywhere but in kernel/sched.c
(e.g. through special define in sched.c before any includes).
Jakub
next reply other threads:[~2003-03-13 11:08 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-13 11:19 Jakub Jelinek [this message]
2003-03-17 6:26 ` Why is get_current() not const function? Linus Torvalds
[not found] <20030313061926.S3910@devserv.devel.redhat.com.suse.lists.linux.kernel>
2003-03-13 13:31 ` Andi Kleen
[not found] ` <b53pqi$ud9$1@penguin.transmeta.com.suse.lists.linux.kernel>
2003-03-17 17:26 ` Andi Kleen
2003-03-17 17:39 ` Jakub Jelinek
-- strict thread matches above, loose matches on Subject: below --
2003-03-17 19:11 Manfred Spraul
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=20030313061926.S3910@devserv.devel.redhat.com \
--to=jakub@redhat.com \
--cc=linux-kernel@vger.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