From f30e6d3e419bfb5540fa82ba7eca01d578556e6b Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Fri, 22 Apr 2011 15:13:54 +0200 Subject: firewire: octlet AT payloads can be stack-allocated We do not need slab allocations anymore in order to satisfy streaming DMA mapping constraints, thanks to commit da28947e7e36 "firewire: ohci: avoid separate DMA mapping for small AT payloads". (Besides, the slab-allocated buffers that firewire-core, firewire-sbp2, and firedtv used to provide for 8-byte write and lock requests were still not fully portable since they crossed cacheline boundaries or shared a cacheline with unrelated CPU-accessed data. snd-firewire-lib got this aspect right by using an extra kmalloc/ kfree just for the 8-byte transaction buffer.) This change replaces kmalloc'ed lock transaction scratch buffers in firewire-core, firedtv, and snd-firewire-lib by local stack allocations. Perhaps the most notable result of the change is simpler locking because there is no need to serialize usages of preallocated per-device buffers anymore. Also, allocations and deallocations are simpler. Signed-off-by: Stefan Richter Acked-by: Clemens Ladisch --- sound/firewire/cmp.c | 3 +-- sound/firewire/iso-resources.c | 12 +++--------- sound/firewire/iso-resources.h | 1 - 3 files changed, 4 insertions(+), 12 deletions(-) (limited to 'sound') diff --git a/sound/firewire/cmp.c b/sound/firewire/cmp.c index 4a37f3a6fab..14cacbc655d 100644 --- a/sound/firewire/cmp.c +++ b/sound/firewire/cmp.c @@ -49,10 +49,9 @@ static int pcr_modify(struct cmp_connection *c, enum bus_reset_handling bus_reset_handling) { struct fw_device *device = fw_parent_device(c->resources.unit); - __be32 *buffer = c->resources.buffer; int generation = c->resources.generation; int rcode, errors = 0; - __be32 old_arg; + __be32 old_arg, buffer[2]; int err; buffer[0] = c->last_pcr_value; diff --git a/sound/firewire/iso-resources.c b/sound/firewire/iso-resources.c index 775dbd5f344..bb9c0c1fb52 100644 --- a/sound/firewire/iso-resources.c +++ b/sound/firewire/iso-resources.c @@ -11,7 +11,6 @@ #include #include #include -#include #include #include "iso-resources.h" @@ -25,10 +24,6 @@ */ int fw_iso_resources_init(struct fw_iso_resources *r, struct fw_unit *unit) { - r->buffer = kmalloc(2 * 4, GFP_KERNEL); - if (!r->buffer) - return -ENOMEM; - r->channels_mask = ~0uLL; r->unit = fw_unit_get(unit); mutex_init(&r->mutex); @@ -44,7 +39,6 @@ int fw_iso_resources_init(struct fw_iso_resources *r, struct fw_unit *unit) void fw_iso_resources_destroy(struct fw_iso_resources *r) { WARN_ON(r->allocated); - kfree(r->buffer); mutex_destroy(&r->mutex); fw_unit_put(r->unit); } @@ -131,7 +125,7 @@ retry_after_bus_reset: bandwidth = r->bandwidth + r->bandwidth_overhead; fw_iso_resource_manage(card, r->generation, r->channels_mask, - &channel, &bandwidth, true, r->buffer); + &channel, &bandwidth, true); if (channel == -EAGAIN) { mutex_unlock(&r->mutex); goto retry_after_bus_reset; @@ -184,7 +178,7 @@ int fw_iso_resources_update(struct fw_iso_resources *r) bandwidth = r->bandwidth + r->bandwidth_overhead; fw_iso_resource_manage(card, r->generation, 1uLL << r->channel, - &channel, &bandwidth, true, r->buffer); + &channel, &bandwidth, true); /* * When another bus reset happens, pretend that the allocation * succeeded; we will try again for the new generation later. @@ -220,7 +214,7 @@ void fw_iso_resources_free(struct fw_iso_resources *r) if (r->allocated) { bandwidth = r->bandwidth + r->bandwidth_overhead; fw_iso_resource_manage(card, r->generation, 1uLL << r->channel, - &channel, &bandwidth, false, r->buffer); + &channel, &bandwidth, false); if (channel < 0) dev_err(&r->unit->device, "isochronous resource deallocation failed\n"); diff --git a/sound/firewire/iso-resources.h b/sound/firewire/iso-resources.h index 3f0730e4d84..5a9af7c6165 100644 --- a/sound/firewire/iso-resources.h +++ b/sound/firewire/iso-resources.h @@ -24,7 +24,6 @@ struct fw_iso_resources { unsigned int bandwidth_overhead; int generation; /* in which allocation is valid */ bool allocated; - __be32 *buffer; }; int fw_iso_resources_init(struct fw_iso_resources *r, -- cgit v1.2.3 From 13882a82ee1646336c3996c93b4a560a55d2a419 Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Mon, 2 May 2011 09:33:56 +0200 Subject: firewire: optimize iso queueing by setting wake only after the last packet When queueing iso packets, the run time is dominated by the two MMIO accesses that set the DMA context's wake bit. Because most drivers submit packets in batches, we can save much time by removing all but the last wakeup. The internal kernel API is changed to require a call to fw_iso_context_queue_flush() after a batch of queued packets. The user space API does not change, so one call to FW_CDEV_IOC_QUEUE_ISO must specify multiple packets to take advantage of this optimization. In my measurements, this patch reduces the time needed to queue fifty skip packets from userspace to one sixth on a 2.5 GHz CPU, or to one third at 800 MHz. Signed-off-by: Clemens Ladisch Signed-off-by: Stefan Richter --- sound/firewire/amdtp.c | 1 + 1 file changed, 1 insertion(+) (limited to 'sound') diff --git a/sound/firewire/amdtp.c b/sound/firewire/amdtp.c index b18140ff2b9..87657dd7714 100644 --- a/sound/firewire/amdtp.c +++ b/sound/firewire/amdtp.c @@ -396,6 +396,7 @@ static void out_packet_callback(struct fw_iso_context *context, u32 cycle, for (i = 0; i < packets; ++i) queue_out_packet(s, ++cycle); + fw_iso_context_queue_flush(s->context); } static int queue_initial_skip_packets(struct amdtp_out_stream *s) -- cgit v1.2.3