diff options
author | Patrick Kelsey <pat.kelsey@cornelisnetworks.com> | 2023-04-07 19:52:49 +0300 |
---|---|---|
committer | Leon Romanovsky <leon@kernel.org> | 2023-04-09 13:27:34 +0300 |
commit | 866694afd644cd5ee32411713c3d802fcca22ebb (patch) | |
tree | f7b2f29645181be847f80c6f021d105558e9b752 /drivers/infiniband | |
parent | 00cbce5cbf88459cd1aa1d60d0f1df15477df127 (diff) | |
download | linux-866694afd644cd5ee32411713c3d802fcca22ebb.tar.xz |
IB/hfi1: Place struct mmu_rb_handler on cache line start
Place struct mmu_rb_handler on cache line start like so:
struct mmu_rb_handler *h;
void *free_ptr;
int ret;
free_ptr = kzalloc(sizeof(*h) + cache_line_size() - 1, GFP_KERNEL);
if (!free_ptr)
return -ENOMEM;
h = PTR_ALIGN(free_ptr, cache_line_size());
Additionally, move struct mmu_rb_handler fields "root" and "ops_args" to
start after the next cacheline using the "____cacheline_aligned_in_smp"
annotation.
Allocating an additional cache_line_size() - 1 bytes to place
struct mmu_rb_handler on a cache line start does increase memory
consumption.
However, few struct mmu_rb_handler are created when hfi1 is in use.
As mmu_rb_handler->root and mmu_rb_handler->ops_args are accessed
frequently, the advantage of having them both within a cache line is
expected to outweigh the disadvantage of the additional memory
consumption per struct mmu_rb_handler.
Signed-off-by: Brendan Cunningham <bcunningham@cornelisnetworks.com>
Signed-off-by: Patrick Kelsey <pat.kelsey@cornelisnetworks.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Link: https://lore.kernel.org/r/168088636963.3027109.16959757980497822530.stgit@252.162.96.66.static.eigbox.net
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r-- | drivers/infiniband/hw/hfi1/mmu_rb.c | 11 | ||||
-rw-r--r-- | drivers/infiniband/hw/hfi1/mmu_rb.h | 14 |
2 files changed, 19 insertions, 6 deletions
diff --git a/drivers/infiniband/hw/hfi1/mmu_rb.c b/drivers/infiniband/hw/hfi1/mmu_rb.c index 71b9ac018887..1cea8b0c78e0 100644 --- a/drivers/infiniband/hw/hfi1/mmu_rb.c +++ b/drivers/infiniband/hw/hfi1/mmu_rb.c @@ -46,12 +46,14 @@ int hfi1_mmu_rb_register(void *ops_arg, struct mmu_rb_handler **handler) { struct mmu_rb_handler *h; + void *free_ptr; int ret; - h = kzalloc(sizeof(*h), GFP_KERNEL); - if (!h) + free_ptr = kzalloc(sizeof(*h) + cache_line_size() - 1, GFP_KERNEL); + if (!free_ptr) return -ENOMEM; + h = PTR_ALIGN(free_ptr, cache_line_size()); h->root = RB_ROOT_CACHED; h->ops = ops; h->ops_arg = ops_arg; @@ -62,10 +64,11 @@ int hfi1_mmu_rb_register(void *ops_arg, INIT_LIST_HEAD(&h->del_list); INIT_LIST_HEAD(&h->lru_list); h->wq = wq; + h->free_ptr = free_ptr; ret = mmu_notifier_register(&h->mn, current->mm); if (ret) { - kfree(h); + kfree(free_ptr); return ret; } @@ -108,7 +111,7 @@ void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler) /* Now the mm may be freed. */ mmdrop(handler->mn.mm); - kfree(handler); + kfree(handler->free_ptr); } int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler, diff --git a/drivers/infiniband/hw/hfi1/mmu_rb.h b/drivers/infiniband/hw/hfi1/mmu_rb.h index ed75acdb7b83..c4da064188c9 100644 --- a/drivers/infiniband/hw/hfi1/mmu_rb.h +++ b/drivers/infiniband/hw/hfi1/mmu_rb.h @@ -33,15 +33,25 @@ struct mmu_rb_ops { }; struct mmu_rb_handler { + /* + * struct mmu_notifier is 56 bytes, and spinlock_t is 4 bytes, so + * they fit together in one cache line. mn is relatively rarely + * accessed, so co-locating the spinlock with it achieves much of + * the cacheline contention reduction of giving the spinlock its own + * cacheline without the overhead of doing so. + */ struct mmu_notifier mn; - struct rb_root_cached root; - void *ops_arg; spinlock_t lock; /* protect the RB tree */ + + /* Begin on a new cachline boundary here */ + struct rb_root_cached root ____cacheline_aligned_in_smp; + void *ops_arg; struct mmu_rb_ops *ops; struct list_head lru_list; struct work_struct del_work; struct list_head del_list; struct workqueue_struct *wq; + void *free_ptr; }; int hfi1_mmu_rb_register(void *ops_arg, |