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  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:	Mon, 10 Nov 2014 16:18:36 +0530
From:	Preeti U Murthy <preeti@...ux.vnet.ibm.com>
To:	mpe@...erman.id.au, mikey@...ling.org, joel.stanley@....ibm.com,
	"benh@...nel.crashing.org" <benh@...nel.crashing.org>
CC:	linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
	rjw@...ysocki.net
Subject: Re: [PATCH] cpuidle/powernv: Fix return value of idle index in fastsleep

Hi Ben, Mikey,

Can you please take a look at this patch?  I feel the commit dcb1869 was
just a plug-in solution. Shouldn't we take a look at this again?

Ideally we should not need this check. With the cpuidle redesign on
PowerNV going in, we can enable fastsleep at bootup itself and without
checks on any debug parameters such as powersave_nap .We will then only
need to check for powersave_nap == 0 and return only if that is the
case. This check is still required since the user can disable all deep
idle states by setting powersave_nap to 0.

Regards
Preeti U Murthy

On 10/27/2014 06:56 PM, Preeti U Murthy wrote:
> Commit dcb18694 : Fix ipi on Palmeto added a workaround to disable
> going into fastsleep on Palmeto boards which was reported to fail
> to boot when fastsleep was enabled. However it missed returning
> an idle index. Fix this.
> 
> There is probably no harm in returning the index of fastsleep
> although the cpu did not enter this state. The governor will notice
> the difference in the residency time in the idle state and the
> target residency of the idle state and prevent cpus from entering
> fastsleep from that point on. Hence the usage and time statistics
> logged for fastsleep will not be out of sync with reality except
> for the first entry.
> 
> Signed-off-by: Preeti U Murthy <preeti@...ux.vnet.ibm.com>
> ---
> Do we still need this workaround? Or can we get rid of the check
> on powersave_nap altogether?
> ---
> 
>  drivers/cpuidle/cpuidle-powernv.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
> index fa79392..c18da24 100644
> --- a/drivers/cpuidle/cpuidle-powernv.c
> +++ b/drivers/cpuidle/cpuidle-powernv.c
> @@ -70,7 +70,7 @@ static int fastsleep_loop(struct cpuidle_device *dev,
>  	unsigned long new_lpcr;
>  
>  	if (powersave_nap < 2)
> -		return;
> +		return index;
>  	if (unlikely(system_state < SYSTEM_RUNNING))
>  		return index;
>  
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@...ts.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
> 

--
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/

Powered by blists - more mailing lists