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Date: Tue, 30 Jul 2013 08:08:10 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Michal Hocko <mhocko@suse.cz>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, kosaki.motohiro@jp.fujitsu.com,
        kamezawa.hiroyu@jp.fujitsu.com, bp@suse.de,
        Dave Hansen <dave@linux.vnet.ibm.com>
Subject: Re: [PATCH resend] drop_caches: add some documentation and info
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On Tue, 30 Jul 2013 07:47:12 -0700 Dave Hansen <dave.hansen@intel.com> wrote:

> On 07/30/2013 05:55 AM, Michal Hocko wrote:
> >> > If we add another flag in the future it can use bit 3?
> > What if we get crazy and need more of them?
> 
> I really hate using bits for these kinds of interfaces.  I'm forgetful
> and never remember which bit is which, and they're possible to run out of.
> 
> I'm not saying do it now, but we can switch over to:
> 
> 	echo 'slab|pagecache' > drop_caches
> or
> 	echo 'quiet|slab' > drop_caches
> 
> any time we want and still have compatibility with the existing bitwise
> interface.

	/bin/drop_caches "slab|pagecache"

That we always insist on doing such things in the kernel instead is
exhibit #1 in Why We Suck.