linux-kernel - RE: aio is unlikely

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]

Message-ID: <058f01c7998e$1406e370$650df7cd@MUMBA>
Date:	Fri, 18 May 2007 16:49:49 -0400
From:	"Alex Volkov" <avcp-lkmail@....net>
To:	"'Andrew Morton'" <akpm@...ux-foundation.org>,
	"'Jeff Garzik'" <jeff@...zik.org>
Cc:	"'Linux Kernel Mailing List'" <linux-kernel@...r.kernel.org>
Subject: RE: aio is unlikely


Andrew Morton wrote:
>     aio is unlikely
>     Stick an unlikely() around is_aio(): I assert that most IO is
synchronous.
>
> -#define in_aio() !is_sync_wait(current->io_wait)
> +#define in_aio() (unlikely(!is_sync_wait(current->io_wait)))

> Jeff Garzik <jeff@...zik.org> wrote:
> 
> > > -#define in_aio() !is_sync_wait(current->io_wait)
> > > +#define in_aio() (unlikely(!is_sync_wait(current->io_wait)))
> > 
> > Please revert.  Workload-dependent "likelihood" should not cause 
> > programmers to add such markers.
> a) disagree with the above
> 
> b) if in_aio() ever returns true we do
> 
> 	printk(KERN_ERR "%s(%s:%d) called in async context!\n",
> 		__FUNCTION__, __FILE__, __LINE__);
> 
>    so I sure hope it's unlikely for all workloads. 

Shouldn't unlikely() go where in_aio() is actually used, if we printk(error)
there?
Isn't putting likely/unlikely into a boolean function-like macro itself
asking for later trouble?

--Alex.


-
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/