From 05f6a172967321798f63869d330f88a1bc2c8ed9 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 11 Dec 2007 08:22:53 +0100 Subject: [PATCH] syslet: make sure ring buffer is a power-of-2 Signed-off-by: Jens Axboe --- engines/syslet-rw.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/engines/syslet-rw.c b/engines/syslet-rw.c index d74fcdf8..2e23fc93 100644 --- a/engines/syslet-rw.c +++ b/engines/syslet-rw.c @@ -225,13 +225,30 @@ static int fio_syslet_init(struct thread_data *td) { struct syslet_data *sd; void *ring = NULL, *stack = NULL; + unsigned int ring_size, ring_nr; sd = malloc(sizeof(*sd)); memset(sd, 0, sizeof(*sd)); sd->events = malloc(sizeof(struct io_u *) * td->o.iodepth); memset(sd->events, 0, sizeof(struct io_u *) * td->o.iodepth); - if (posix_memalign(&ring, sizeof(uint64_t), sizeof(struct syslet_ring))) + + /* + * The ring needs to be a power-of-2, so round it up if we have to + */ + ring_nr = td->o.iodepth; + if (ring_nr & (ring_nr - 1)) { + int bits = 1; + + while (ring_nr >>= 1) + bits++; + + ring_nr = 1 << bits; + } + + ring_size = sizeof(struct syslet_ring) + + ring_nr * sizeof(struct syslet_completion); + if (posix_memalign(&ring, sizeof(uint64_t), ring_size)) goto err_mem; if (posix_memalign(&stack, page_size, page_size)) goto err_mem; @@ -239,8 +256,8 @@ static int fio_syslet_init(struct thread_data *td) sd->ring = ring; sd->stack = stack; - memset(sd->ring, 0, sizeof(*sd->ring)); - sd->ring->elements = td->o.iodepth; + memset(sd->ring, 0, ring_size); + sd->ring->elements = ring_nr; if (!check_syslet_support(sd)) { td->io_ops->data = sd; -- 2.25.1