Re: [RFC] /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages

[Michal Hocko <mhocko@suse.cz>]

On Wed 05-01-11 11:42:01, CAI Qian wrote:
> 
> 
> ----- Original Message -----
> > On Wed 05-01-11 10:36:47, CAI Qian wrote:
> > > From f90b54f9f5607128e375bd78d21e751c433b3cf6 Mon Sep 17 00:00:00
> > > 2001
> > > From: CAI Qian <caiqian@redhat.com>
> > > Date: Wed, 5 Jan 2011 23:26:57 +0800
> > > Subject: [PATCH] hugetlbfs: check invalid nr_hugepages and
> > > nr_overcommit_hugepages
> > >
> > > First, nr_*hugepages* in procfs and sysfs do not check for invalid
> > > input like "". Second, when using oversize pages, nr_*hugepages* are
> > > expected to be allocated during boot time. Therefore, return -EINVAL
> > > for those cases.
> > 
> > I think that the two things should be split into two patches - one for
> > the proper input data handling and the other one for the size check.
> > Albeit, I am not sure about the size check because this is a thing
> > that is just a current implementation limitation and can be change later.
> OK, will do two patches.

Then you can use the patch I sent earlier and make just a size check
patch on top of it, right?

> 
> > > Signed-off-by: CAI Qian <caiqian@redhat.com>
> > > ---
> > >  fs/sysfs/file.c | 2 ++
> > >  mm/hugetlb.c | 18 ++++++++++++++++--
> > >  2 files changed, 18 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
> > > index da3fefe..9f4ea67 100644
> > > --- a/fs/sysfs/file.c
> > > +++ b/fs/sysfs/file.c
> > > @@ -207,6 +207,8 @@ flush_write_buffer(struct dentry * dentry,
> > > struct sysfs_buffer * buffer, size_t
> > >  		return -ENODEV;
> > >
> > >  	rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count);
> > > + if (!rc)
> > > + return -EINVAL;
> > 
> > This doesn't look correct, you would imbalance sysfs_{get,put}_active.
> Right, I'll fix this up.
> 
> Thanks.
> 
> CAI Qian

-- 
Michal Hocko
L3 team 
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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