linux-kernel - Re: [PATCH resend] drop_caches: add some documentation and info message

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: <20130730074531.GA10584@dhcp22.suse.cz>
Date:	Tue, 30 Jul 2013 09:45:31 +0200
From:	Michal Hocko <mhocko@...e.cz>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	dave.hansen@...el.com, kosaki.motohiro@...fujitsu.com,
	kamezawa.hiroyu@...fujitsu.com, bp@...e.de,
	Dave Hansen <dave@...ux.vnet.ibm.com>
Subject: Re: [PATCH resend] drop_caches: add some documentation and info
 message

On Mon 29-07-13 13:57:43, Andrew Morton wrote:
> On Fri, 26 Jul 2013 14:44:29 +0200 Michal Hocko <mhocko@...e.cz> wrote:
[...]
> > --- a/fs/drop_caches.c
> > +++ b/fs/drop_caches.c
> > @@ -59,6 +59,8 @@ int drop_caches_sysctl_handler(ctl_table *table, int write,
> >  	if (ret)
> >  		return ret;
> >  	if (write) {
> > +		printk(KERN_INFO "%s (%d): dropped kernel caches: %d\n",
> > +		       current->comm, task_pid_nr(current), sysctl_drop_caches);
> >  		if (sysctl_drop_caches & 1)
> >  			iterate_supers(drop_pagecache_sb, NULL);
> >  		if (sysctl_drop_caches & 2)
> 
> How about we do
> 
> 	if (!(sysctl_drop_caches & 4))
> 		printk(....)
>
> so people can turn it off if it's causing problems?

I am OK with that  but can we use a top bit instead. Maybe we never have
other entities to drop in the future but it would be better to have a room for them
just in case. So what about using 1<<31 instead?


-- 
Michal Hocko
SUSE Labs
--
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/