Hello Yuval, +-- On Sun, 16 Dec 2018, Yuval Shaia wrote --+ | With this patch the last step fails, the guest OS hangs, trying to probably | unload pvrdma driver and finally gave up after 3 minutes.
Strange... | Anyways with debug turned on i have noticed that there is one case that | devices gets 129 nchunks (i think in MPI) while your patch limits it to 128. | >From pvrdma source code we can see that first page is dedicated to ring | state, this means that it maybe correct that 128 is the limit but we | should check that nchunks does not exceed 129, not 128. | | What do you think? -> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/infiniband/hw/vmw_pvrdma/pvrdma_mr.c?id=fdf82a7856b32d905c39afc85e34364491e46346#n201 the vmw_pvrdma kernel driver also seems to set MAX_FAST_REG_PAGE = 128. | Ie. to replace this line from create_cq_ring | + if (!nchunks || nchunks > PVRDMA_MAX_FAST_REG_PAGES) { | with this | + if (!nchunks || nchunks > PVRDMA_MAX_FAST_REG_PAGES + 1) { | | Let me know your opinion. While it may help to fix the regression. I'm not sure it's a right fix. 129 seems a little odd number to have as limit. Is it possible MPI is erring in getting 129 chunks? IMO it's better to confirm the right value for 'MAX_FAST_REG_PAGES', before going with > PVRDMA_MAX_FAS_REG_PAGES(=128) + 1. Thank you. -- Prasad J Pandit / Red Hat Product Security Team 47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F
