On Thu, Mar 10, 2011 at 02:37:51AM -0500, Christoph Hellwig wrote: > On Thu, Mar 10, 2011 at 10:37:56AM +1100, Dave Chinner wrote: > > From: Dave Chinner <dchinner@xxxxxxxxxx> > > > > On 32 bit systems, vmalloc space is limited and XFS can chew through > > it quickly as the vmalloc space is lazily freed. This can result in > > failure to map buffers, even when there is apparently large amounts > > of vmalloc space available. Hence, if we fail to map a buffer, purge > > the aliases that have not yet been freed to hopefuly free up enough > > vmalloc space to allow a retry to succeed. > > IMHO this should be done by vm_map_ram internally. If we can't get the > core code fixes we can put this in as a last resort. OK. The patch was done as part of the triage for this bug: https://bugzilla.kernel.org/show_bug.cgi?id=27492 where the vmalloc space on 32 bit systems is getting exhausted. I can easily move this flush-and-retry into the vmap code. FWIW, while the VM folk might be paying attention about vmap realted stuff, this vmap BUG() also needs triage: https://bugzilla.kernel.org/show_bug.cgi?id=27002 And, finally, the mm-vmap-area-cache.patch in the current mmotm also needs to be pushed forward because we've been getting reports of excessive CPU time being spent walking the vmap area rbtree during vm_map_ram operations and this patch supposedly fixes that problem.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>