diff options
| author | Gerd Rausch <gerd.rausch@oracle.com> | 2019-07-16 15:28:51 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-07-17 12:06:51 -0700 |
| commit | 2c7da8e6b041a8df2661def81ac90c9c0c719909 (patch) | |
| tree | 52734d4a773975166c4a839c3e8927d8f1c1f70e /net | |
| parent | f11fe1dae1c46762a9a7b0dd142b6bfebe7783ff (diff) | |
net/rds: Give fr_state a chance to transition to FRMR_IS_FREE
In the context of FRMR (ib_frmr.c):
Memory regions make it onto the "clean_list" via "rds_ib_flush_mr_pool",
after the memory region has been posted for invalidation via
"rds_ib_post_inv".
At that point in time, "fr_state" may still be in state "FRMR_IS_INUSE",
since the only place where "fr_state" transitions to "FRMR_IS_FREE"
is in "rds_ib_mr_cqe_handler", which is triggered by a tasklet.
So in case we notice that "fr_state != FRMR_IS_FREE" (see below),
we wait for "fr_inv_done" to trigger with a maximum of 10msec.
Then we check again, and only put the memory region onto the drop_list
(via "rds_ib_free_frmr") in case the situation remains unchanged.
This avoids the problem of memory-regions bouncing between "clean_list"
and "drop_list" before they even have a chance to be properly invalidated.
Signed-off-by: Gerd Rausch <gerd.rausch@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/rds/ib_frmr.c | 27 | ||||
| -rw-r--r-- | net/rds/ib_mr.h | 1 |
2 files changed, 27 insertions, 1 deletions
diff --git a/net/rds/ib_frmr.c b/net/rds/ib_frmr.c index 32ae26ed58a0..6038138d6e38 100644 --- a/net/rds/ib_frmr.c +++ b/net/rds/ib_frmr.c @@ -75,6 +75,7 @@ static struct rds_ib_mr *rds_ib_alloc_frmr(struct rds_ib_device *rds_ibdev, pool->max_items_soft = pool->max_items; frmr->fr_state = FRMR_IS_FREE; + init_waitqueue_head(&frmr->fr_inv_done); return ibmr; out_no_cigar: @@ -285,6 +286,7 @@ void rds_ib_mr_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc) if (frmr->fr_inv) { frmr->fr_state = FRMR_IS_FREE; frmr->fr_inv = false; + wake_up(&frmr->fr_inv_done); } atomic_inc(&ic->i_fastreg_wrs); @@ -345,8 +347,31 @@ struct rds_ib_mr *rds_ib_reg_frmr(struct rds_ib_device *rds_ibdev, } do { - if (ibmr) + if (ibmr) { + /* Memory regions make it onto the "clean_list" via + * "rds_ib_flush_mr_pool", after the memory region has + * been posted for invalidation via "rds_ib_post_inv". + * + * At that point in time, "fr_state" may still be + * in state "FRMR_IS_INUSE", since the only place where + * "fr_state" transitions to "FRMR_IS_FREE" is in + * is in "rds_ib_mr_cqe_handler", which is + * triggered by a tasklet. + * + * So we wait for "fr_inv_done" to trigger + * and only put memory regions onto the drop_list + * that failed (i.e. not marked "FRMR_IS_FREE"). + * + * This avoids the problem of memory-regions bouncing + * between "clean_list" and "drop_list" before they + * even have a chance to be properly invalidated. + */ + frmr = &ibmr->u.frmr; + wait_event(frmr->fr_inv_done, frmr->fr_state != FRMR_IS_INUSE); + if (frmr->fr_state == FRMR_IS_FREE) + break; rds_ib_free_frmr(ibmr, true); + } ibmr = rds_ib_alloc_frmr(rds_ibdev, nents); if (IS_ERR(ibmr)) return ibmr; diff --git a/net/rds/ib_mr.h b/net/rds/ib_mr.h index 5da12c248431..42daccb7b5eb 100644 --- a/net/rds/ib_mr.h +++ b/net/rds/ib_mr.h @@ -57,6 +57,7 @@ struct rds_ib_frmr { struct ib_mr *mr; enum rds_ib_fr_state fr_state; bool fr_inv; + wait_queue_head_t fr_inv_done; struct ib_send_wr fr_wr; unsigned int dma_npages; unsigned int sg_byte_len; |