Messages in this thread | | | Subject | Re: [Ext2-devel] Re: 2.4.6 and ext3-2.4-0.9.1-246 | Date | Fri, 13 Jul 2001 12:27:33 -0500 | From | Steve Lord <> |
| |
> Hi, > > On Fri, Jul 13, 2001 at 09:54:56AM -0400, Mike Black wrote: > > I give up! I'm getting file system corruption now on the ext3 partition... > > and I've got a kernel oops (soon to be decoded) > > Please, do send details. We already know that the VM has a hard job > under load, and journaling exacerbates that --- ext3 cannot always > write to disk without first allocating more memory, and the VM simply > doesn't have a mechanism for dealing with that reliably. It seems to > be compounded by (a) 2.4 having less write throttling than 2.2 had, > and (b) the zoned allocator getting confused about which zones > actually need to be recycled.
We seem to have managed to keep XFS going without the memory reservation scheme - and the way we do I/O on metadata right now means there is always a memory allocation in that path. At the moment the only thing I can kill the system with is make -j bzImage it eventually grinds to a halt with the swapper waiting for a request slot in the block layer but the system is in such a mess that I have not been able to diagnose it further than that.
A lot of careful use of GFP flags on memory allocation was necessary to get to this point, the GFP_NOIO and GFP_NOFS finally made this deadlock clean.
Steve
> > It's not just ext3 --- highmem bounce buffering and soft raid buffers > have the same problem, and work around it by doing their own internal > preallocation of emergency buffers. Loop devices and nbd will have a > similar problem if you use those for swap or writable mmaps, as will > NFS. > > One proposed suggestion is to do per-zone memory reservations for the > VM's use: Ben LaHaise has prototype code for that and we'll be testing > to see if it makes for an improvement when used with ext3. > > Cheers, > Stephen > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |