diff options
| author | Olaf Kirch <okir@lst.de> | 2008-04-29 13:46:53 -0700 |
|---|---|---|
| committer | Roland Dreier <rolandd@cisco.com> | 2008-04-29 13:46:53 -0700 |
| commit | 0bfe151cc4049f3f304adf28b37ea5437d02ad96 (patch) | |
| tree | 4e67ca79ec441896bd9cfde98268eb287987989e /drivers/infiniband/hw | |
| parent | bbdc2821db041fb07ffa52e4a0e1ebb5410790e9 (diff) | |
IB/mthca: Avoid recycling old FMR R_Keys too soon
When a FMR is unmapped, mthca resets the map count to 0, and clears
the upper part of the R_Key which is used as the sequence counter.
This poses a problem for RDS, which uses ib_fmr_unmap as a fence
operation. RDS assumes that after issuing an unmap, the old R_Keys
will be invalid for a "reasonable" period of time. For instance,
Oracle processes uses shared memory buffers allocated from a pool of
buffers. When a process dies, we want to reclaim these buffers -- but
we must make sure there are no pending RDMA operations to/from those
buffers. The only way to achieve that is by using unmap and sync the
TPT.
However, when the sequence count is reset on unmap, there is a high
likelihood that a new mapping will be given the same R_Key that was
issued a few milliseconds ago.
To prevent this, don't reset the sequence count when unmapping a FMR.
Signed-off-by: Olaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Diffstat (limited to 'drivers/infiniband/hw')
| -rw-r--r-- | drivers/infiniband/hw/mthca/mthca_mr.c | 13 |
1 files changed, 0 insertions, 13 deletions
diff --git a/drivers/infiniband/hw/mthca/mthca_mr.c b/drivers/infiniband/hw/mthca/mthca_mr.c index 3538da16e3fe..820205dec560 100644 --- a/drivers/infiniband/hw/mthca/mthca_mr.c +++ b/drivers/infiniband/hw/mthca/mthca_mr.c @@ -818,15 +818,9 @@ int mthca_arbel_map_phys_fmr(struct ib_fmr *ibfmr, u64 *page_list, void mthca_tavor_fmr_unmap(struct mthca_dev *dev, struct mthca_fmr *fmr) { - u32 key; - if (!fmr->maps) return; - key = tavor_key_to_hw_index(fmr->ibmr.lkey); - key &= dev->limits.num_mpts - 1; - fmr->ibmr.lkey = fmr->ibmr.rkey = tavor_hw_index_to_key(key); - fmr->maps = 0; writeb(MTHCA_MPT_STATUS_SW, fmr->mem.tavor.mpt); @@ -834,16 +828,9 @@ void mthca_tavor_fmr_unmap(struct mthca_dev *dev, struct mthca_fmr *fmr) void mthca_arbel_fmr_unmap(struct mthca_dev *dev, struct mthca_fmr *fmr) { - u32 key; - if (!fmr->maps) return; - key = arbel_key_to_hw_index(fmr->ibmr.lkey); - key &= dev->limits.num_mpts - 1; - key = adjust_key(dev, key); - fmr->ibmr.lkey = fmr->ibmr.rkey = arbel_hw_index_to_key(key); - fmr->maps = 0; *(u8 *) fmr->mem.arbel.mpt = MTHCA_MPT_STATUS_SW; |