Re: Limit hash table size

Andrew Morton
2004-02-06T03:11:04Z

Steve Lord <lord@xfs.org> wrote:
>
> I have seen some dire cases with the dcache, SGI had some boxes with
> millions of files out there, and every night a cron job would come
> along and suck them all into memory. Resources got tight at some point,
> and as more inodes and dentries were being read in, the try to free
> pages path was continually getting called. There was always something
> in filesystem cache which could get freed, and the inodes and dentries
> kept getting more and more of the memory.

There are a number of variables here. Certainly, the old
inodes-pinned-by-highmem pagecache will cause this to happen - badly. 2.6
is pretty aggressive at killing off those inodes.

What kernel was it?

Was it a highmem box? If so, was the filesystem in question placing
directory pagecache in highmem? If so, that was really bad on older 2.4:
the directory pagecache in highmem pins down all directory inodes.