[lkml]   [2007]   [Jan]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC 8/8] Reduce inode memory usage for systems with a high MAX_NUMNODES
On 1/16/07, Christoph Lameter <> wrote:
> On Tue, 16 Jan 2007, Paul Menage wrote:
> > On 1/15/07, Christoph Lameter <> wrote:
> > >
> > > This solution may be a bit hokey. I tried other approaches but this
> > > one seemed to be the simplest with the least complications. Maybe someone
> > > else can come up with a better solution?
> >
> > How about a 64-bit field in struct inode that's used as a bitmask if
> > there are no more than 64 nodes, and a pointer to a bitmask if there
> > are more than 64 nodes. The filesystems wouldn't need to be involved
> > then, as the bitmap allocation could be done in the generic code.
> How would we decide if there are more than 64 nodes? Runtime or compile
> time?

I was thinking runtime, unless MAX_NUMNODES is less than 64 in which
case you can make the decision at compile time.

> If done at compile time then we will end up with a pointer to an unsigned
> long for a system with <= 64 nodes. If we allocate the nodemask via
> kmalloc then we will always end up with a mininum allocation size of 64
> bytes.

Can't we get less overhead with a slab cache with appropriate-sized objects?

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-01-16 21:37    [W:0.089 / U:6.096 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site