On Thu, 27 Jan 2011 09:23:20 +0100 Michal Hocko <mhocko@xxxxxxx> wrote: > On Wed 26-01-11 14:06:18, Andrew Morton wrote: > > On Wed, 26 Jan 2011 16:21:58 +0100 > > Michal Hocko <mhocko@xxxxxxx> wrote: > > > > > I am sorry but the patch which added swapaccount parameter is not > > > correct (we have discussed it https://lkml.org/lkml/2010/11/16/103). > > > I didn't get the way how __setup parameters are handled correctly. > > > The patch bellow fixes that. > > > > > > I am CCing stable as well because the patch got into .37 kernel. > > > > > > --- > > > >From 144c2e8aed27d82d48217896ee1f58dbaa7f1f84 Mon Sep 17 00:00:00 2001 > > > From: Michal Hocko <mhocko@xxxxxxx> > > > Date: Wed, 26 Jan 2011 14:12:41 +0100 > > > Subject: [PATCH] memsw: handle swapaccount kernel parameter correctly > > > > > > __setup based kernel command line parameters handled in > > > obsolete_checksetup provides the parameter value including = (more > > > precisely everything right after the parameter name) so we have to check > > > for =0 resp. =1 here. If no value is given then we get an empty string > > > rather then NULL. > > > > This doesn't provide a description of the bug which just got fixed. > > > > From reading the code I think the current behaviour is > > > > "swapaccount": works OK > > Not really because the original test was !s || s="1" but as I am writing > in the commit message we are getting an empty string rather than NULL in > no parameter value case.. > So noswapaccount is actually the only thing that is working. > > > "noswapaccount": works OK > > "swapaccount=0": doesn't do anything > > "swapaccount=1": doesn't do anything > > > > but I might be wrong about that. Please send a changelog update to > > clarify all this. > > Sorry for not being specific enough. What about somthing like this: > --- > From 317dec3d13ef7f11e8f2699331bc32fcd6a8ea0e Mon Sep 17 00:00:00 2001 > From: Michal Hocko <mhocko@xxxxxxx> > Date: Wed, 26 Jan 2011 14:12:41 +0100 > Subject: [PATCH] memsw: handle swapaccount kernel parameter correctly > > __setup based kernel command line parameters handlers which are handled in > obsolete_checksetup are provided with the parameter value including = > (more precisely everything right after the parameter name). > > This means that the current implementation of swapaccount[=1|0] doesn't > work at all because if there is a value for the parameter then we are > testing for "0" resp. "1" but we are getting "=0" resp. "=1" and if > there is no parameter value we are getting an empty string rather than > NULL. > > The original noswapccount parameter, which doesn't care about the value, > works correctly. > > Signed-off-by: Michal Hocko <mhocko@xxxxxxx> > --- > mm/memcontrol.c | 6 +++--- > 1 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index db76ef7..cea2be48 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -5013,9 +5013,9 @@ struct cgroup_subsys mem_cgroup_subsys = { > static int __init enable_swap_account(char *s) > { > /* consider enabled if no parameter or 1 is given */ > - if (!s || !strcmp(s, "1")) > + if (!(*s) || !strcmp(s, "=1")) > really_do_swap_account = 1; > - else if (!strcmp(s, "0")) > + else if (!strcmp(s, "=0")) > really_do_swap_account = 0; > return 1; > } Hmm, usual callser of __setup() includes '=' to parameter name, as mm/hugetlb.c:__setup("hugepages=", hugetlb_nrpages_setup); mm/hugetlb.c:__setup("default_hugepagesz=", hugetlb_default_setup); How about moving "=" to __setup() ? Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>