On Sun, Mar 08, 2015 at 11:35:59AM -0700, Linus Torvalds wrote: > On Sun, Mar 8, 2015 at 3:02 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote: > But: > > > As a second hack (not to be applied), could we change: > > > > #define _PAGE_BIT_PROTNONE _PAGE_BIT_GLOBAL > > > > to: > > > > #define _PAGE_BIT_PROTNONE (_PAGE_BIT_GLOBAL+1) > > > > to double check that the position of the bit does not matter? > > Agreed. We should definitely try that. > > Dave? As Mel has already mentioned, I'm in Boston for LSFMM and don't have access to the test rig I've used to generate this. > Also, is there some sane way for me to actually see this behavior on a > regular machine with just a single socket? Dave is apparently running > in some fake-numa setup, I'm wondering if this is easy enough to > reproduce that I could see it myself. Should be - I don't actually use 500TB of storage to generate this - 50GB on an SSD is all you need from the storage side. I just use a sparse backing file to make it look like a 500TB device. :P i.e. create an XFS filesystem on a 500TB sparse file with "mkfs.xfs -d size=500t,file=1 /path/to/file.img", mount it on loopback or as a virtio,cache=none device for the guest vm and then use fsmark to generate several million files spread across many, many directories such as: $ fs_mark -D 10000 -S0 -n 100000 -s 1 -L 32 -d \ /mnt/scratch/0 -d /mnt/scratch/1 -d /mnt/scratch/2 -d \ /mnt/scratch/3 -d /mnt/scratch/4 -d /mnt/scratch/5 -d \ /mnt/scratch/6 -d /mnt/scratch/7 That should only take a few minutes to run - if you throw 8p at it then it should run at >100k files/s being created. Then unmount and run "xfs_repair -o bhash=101703 /path/to/file.img" on the resultant image file. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
