Re: [Bug 3268] New: Lowmemory exhaustion problem with v2.6.8.1-mm4 16gb

On Wed, 2004-08-25 at 13:37, Hugh Dickins wrote:

On Wed, 25 Aug 2004, keith wrote:

quoted

I turned CONFIG_DEBUG_PAGEALLOC off.

Good, thanks.

quoted

I ran into problems when I tried
building 60 kernel trees or so.  It is using about 10gb of tmpfs space. 
See http://bugme.osdl.org/attachment.cgi?id=3566&action=view for more
info.

Okay, that's more to the point.

quoted

It looks like there should be a maximum number of inodes for tmpfs.
Because I didn't know how many inodes it is using but I gave it a large
playground to use (mount -t tmpfs -o size=15G,nr_inodes=10000k,mode=0700
tmpfs /mytmpfs)

Well, by default it does give you a maximum number of inodes for tmpfs:
which at 16GB of RAM (in 4KB pages: odd that that factors in, but I've
no great urge to depart from existing defaults except where it's buggy)
would give you 2M inodes.  But since each might roughly be expected to
consume 1KB (a shmem_inode, a dentry, a longer name, a radix node) of
low memory, we'd want 2GB of lowmem to support all those: too much.

I think there is a need for a hard upper limit to the number of inodes
tmpfs can use.  With this system I can have 32gb of memory and I also
have a 64gb(i386) system. tempfs sizes above 15=g are definitely
possible.  What about a 40gig tmpfs.... 

So, how well does the patch below work for you, if you leave nr_inodes
to its default?  Carry on setting size=15G, that should be okay; but
I don't think the kernel should stop you if you insist on setting
nr_inodes to something unfortunate like 10M.  "df -i" will show
how many inodes it's actually giving you by default.

I was wondering how to do that thanks. 
With the patch I only get 82294 inodes.  Hmmmm.... I don't have any
lowmem issues but I can't create too many files.  

Thanks,
  Keith Mannthey 

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