linux-kernel - Re: [FOR REVIEW, PATCH 2/2] introduce "struct wait_opts" to simplify do

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu,  7 May 2009 00:20:03 -0700 (PDT)
From:	Roland McGrath <roland@...hat.com>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [FOR REVIEW, PATCH 2/2] introduce "struct wait_opts" to
	simplify do_wait() pathes

> Yes, I considered this option too. But since (I hope) you do not have
> a strong opinion on this, I'd prefer to keep the code as is. This way
> do_wait() looks more symmetrical wrt to other helpers. And we don't
> copy args twice.

I don't feel strongly.  But I do think that those two repeated assignment
blocks are more to read and harder to read, and more error-prone for drift
in future changes (vs prototype changes getting quick compilation errors).
do_wait() is not "another helper", it's the main function.  On machines
with 6 argument registers (everything but x86-32?), the compiler probably
does fine making the callers' register shuffling be free.  On x86-32, a few
cache-hot stack stores and loads are in the tiny noise vs the whole cost of
this hairy syscall, and IMHO don't compare to source maintainability issues.

Thanks,
Roland
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/