From 7be85676f1d13c77a7e0c72e04903bfd39580d4f Mon Sep 17 00:00:00 2001 From: Sebastian Sanchez Date: Fri, 26 May 2017 05:35:12 -0700 Subject: [PATCH] IB/hfi1: Don't remove RB entry when not needed. An RB tree is used for the SDMA pinning cache. Cache entries are extracted and reinserted from the tree in case the address range for it changes. However, if the address range for the entry doesn't change, deleting the entry from the RB tree is not necessary. This affects performance since the tree needs to be rebalanced for each insertion, and this happens in the hot path. Optimize RB search by not removing entries when it's not needed. Reviewed-by: Mike Marciniszyn Reviewed-by: Mitko Haralanov Signed-off-by: Sebastian Sanchez Signed-off-by: Dennis Dalessandro Signed-off-by: Doug Ledford --- drivers/infiniband/hw/hfi1/mmu_rb.c | 14 ++++++++++---- drivers/infiniband/hw/hfi1/mmu_rb.h | 5 +++-- drivers/infiniband/hw/hfi1/user_sdma.c | 21 +++++++++++++++------ 3 files changed, 28 insertions(+), 12 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/mmu_rb.c b/drivers/infiniband/hw/hfi1/mmu_rb.c index ccbf52c8ff6f..d41fd87a39f2 100644 --- a/drivers/infiniband/hw/hfi1/mmu_rb.c +++ b/drivers/infiniband/hw/hfi1/mmu_rb.c @@ -217,21 +217,27 @@ static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler, return node; } -struct mmu_rb_node *hfi1_mmu_rb_extract(struct mmu_rb_handler *handler, - unsigned long addr, unsigned long len) +bool hfi1_mmu_rb_remove_unless_exact(struct mmu_rb_handler *handler, + unsigned long addr, unsigned long len, + struct mmu_rb_node **rb_node) { struct mmu_rb_node *node; unsigned long flags; + bool ret = false; spin_lock_irqsave(&handler->lock, flags); node = __mmu_rb_search(handler, addr, len); if (node) { + if (node->addr == addr && node->len == len) + goto unlock; __mmu_int_rb_remove(node, &handler->root); list_del(&node->list); /* remove from LRU list */ + ret = true; } +unlock: spin_unlock_irqrestore(&handler->lock, flags); - - return node; + *rb_node = node; + return ret; } void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg) diff --git a/drivers/infiniband/hw/hfi1/mmu_rb.h b/drivers/infiniband/hw/hfi1/mmu_rb.h index 754f6ebf13fb..f04cec1e99d1 100644 --- a/drivers/infiniband/hw/hfi1/mmu_rb.h +++ b/drivers/infiniband/hw/hfi1/mmu_rb.h @@ -81,7 +81,8 @@ int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler, void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg); void hfi1_mmu_rb_remove(struct mmu_rb_handler *handler, struct mmu_rb_node *mnode); -struct mmu_rb_node *hfi1_mmu_rb_extract(struct mmu_rb_handler *handler, - unsigned long addr, unsigned long len); +bool hfi1_mmu_rb_remove_unless_exact(struct mmu_rb_handler *handler, + unsigned long addr, unsigned long len, + struct mmu_rb_node **rb_node); #endif /* _HFI1_MMU_RB_H */ diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c index 16fd519216dc..79450cf2a3d5 100644 --- a/drivers/infiniband/hw/hfi1/user_sdma.c +++ b/drivers/infiniband/hw/hfi1/user_sdma.c @@ -1165,14 +1165,23 @@ static int pin_vector_pages(struct user_sdma_request *req, struct hfi1_user_sdma_pkt_q *pq = req->pq; struct sdma_mmu_node *node = NULL; struct mmu_rb_node *rb_node; + bool extracted; - rb_node = hfi1_mmu_rb_extract(pq->handler, - (unsigned long)iovec->iov.iov_base, - iovec->iov.iov_len); - if (rb_node) + extracted = + hfi1_mmu_rb_remove_unless_exact(pq->handler, + (unsigned long) + iovec->iov.iov_base, + iovec->iov.iov_len, &rb_node); + if (rb_node) { node = container_of(rb_node, struct sdma_mmu_node, rb); - else - rb_node = NULL; + if (!extracted) { + atomic_inc(&node->refcount); + iovec->pages = node->pages; + iovec->npages = node->npages; + iovec->node = node; + return 0; + } + } if (!node) { node = kzalloc(sizeof(*node), GFP_KERNEL);