| Message ID | 20240823183856.561166-1-visitorckw@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | crypto: hisilicon/zip - Optimize performance by replacing rw_lock with spinlock | expand |
On Sat, Aug 24, 2024 at 02:38:56AM +0800, Kuan-Wei Chiu wrote: > The req_lock is currently implemented as a rw_lock, but there are no > instances where read_lock() is called. This means that the lock is > effectively only used by writers, making it functionally equivalent to > a simple spinlock. > > As stated in Documentation/locking/spinlocks.rst: > "Reader-writer locks require more atomic memory operations than simple > spinlocks. Unless the reader critical section is long, you are better > off just using spinlocks." > > Since the rw_lock in this case incurs additional atomic memory > operations without any benefit from reader-writer locking, it is more > efficient to replace it with a spinlock. This patch implements that > replacement to optimize the driver's performance. > > Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> > --- > Note: Build test only. > > drivers/crypto/hisilicon/zip/zip_crypto.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) Patch applied. Thanks.
diff --git a/drivers/crypto/hisilicon/zip/zip_crypto.c b/drivers/crypto/hisilicon/zip/zip_crypto.c index 94e2d66b04b6..92d3bd0dfe1b 100644 --- a/drivers/crypto/hisilicon/zip/zip_crypto.c +++ b/drivers/crypto/hisilicon/zip/zip_crypto.c @@ -54,7 +54,7 @@ struct hisi_zip_req { struct hisi_zip_req_q { struct hisi_zip_req *q; unsigned long *req_bitmap; - rwlock_t req_lock; + spinlock_t req_lock; u16 size; }; @@ -116,17 +116,17 @@ static struct hisi_zip_req *hisi_zip_create_req(struct hisi_zip_qp_ctx *qp_ctx, struct hisi_zip_req *req_cache; int req_id; - write_lock(&req_q->req_lock); + spin_lock(&req_q->req_lock); req_id = find_first_zero_bit(req_q->req_bitmap, req_q->size); if (req_id >= req_q->size) { - write_unlock(&req_q->req_lock); + spin_unlock(&req_q->req_lock); dev_dbg(&qp_ctx->qp->qm->pdev->dev, "req cache is full!\n"); return ERR_PTR(-EAGAIN); } set_bit(req_id, req_q->req_bitmap); - write_unlock(&req_q->req_lock); + spin_unlock(&req_q->req_lock); req_cache = q + req_id; req_cache->req_id = req_id; @@ -140,9 +140,9 @@ static void hisi_zip_remove_req(struct hisi_zip_qp_ctx *qp_ctx, { struct hisi_zip_req_q *req_q = &qp_ctx->req_q; - write_lock(&req_q->req_lock); + spin_lock(&req_q->req_lock); clear_bit(req->req_id, req_q->req_bitmap); - write_unlock(&req_q->req_lock); + spin_unlock(&req_q->req_lock); } static void hisi_zip_fill_addr(struct hisi_zip_sqe *sqe, struct hisi_zip_req *req) @@ -456,7 +456,7 @@ static int hisi_zip_create_req_q(struct hisi_zip_ctx *ctx) goto err_free_comp_q; } - rwlock_init(&req_q->req_lock); + spin_lock_init(&req_q->req_lock); req_q->q = kcalloc(req_q->size, sizeof(struct hisi_zip_req), GFP_KERNEL);
The req_lock is currently implemented as a rw_lock, but there are no instances where read_lock() is called. This means that the lock is effectively only used by writers, making it functionally equivalent to a simple spinlock. As stated in Documentation/locking/spinlocks.rst: "Reader-writer locks require more atomic memory operations than simple spinlocks. Unless the reader critical section is long, you are better off just using spinlocks." Since the rw_lock in this case incurs additional atomic memory operations without any benefit from reader-writer locking, it is more efficient to replace it with a spinlock. This patch implements that replacement to optimize the driver's performance. Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> --- Note: Build test only. drivers/crypto/hisilicon/zip/zip_crypto.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)