On 26. 06. 23 15:15, Takashi Iwai wrote:
On Mon, 26 Jun 2023 13:13:21 +0200,
Takashi Iwai wrote:
On Mon, 26 Jun 2023 13:09:00 +0200,
Jaroslav Kysela wrote:
On 26. 06. 23 13:02, Takashi Iwai wrote:
On Mon, 26 Jun 2023 09:56:47 +0200,
Jaroslav Kysela wrote:
On 26. 06. 23 9:33, Takashi Iwai wrote:
On Mon, 26 Jun 2023 09:31:18 +0200,
Tuo Li wrote:
Hello,
Thank you for your reply!
FWIW, the simplest fix would be something like below, just extending
the mutex coverage. But it'll serialize the all calls, so it might
influence on the performance, while it's the safest way.
It may be better to update total_pcm_alloc_bytes before
snd_dma_alloc_dir_pages() call and decrease this value when allocation
fails to allow parallel allocations. Then the mutex can be held only
for the total_pcm_alloc_bytes variable update.
Yes, it'd work. But a tricky part is that the actual allocation size
can be bigger, and we need to correct the total_pcm_alloc_bytes after
the allocation result. So the end result would be a patch like below,
which is a bit more complex than the previous simpler approach. But
it might be OK.
The patch looks good, but it may be better to move the "post" variable
updates to an inline function (mutex lock - update - mutex unlock) for
a better readability.
Sounds like a good idea. Let me cook later.
... and here it is.
If that looks OK, I'll submit a proper fix patch.
thanks,
Takashi
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -31,15 +31,41 @@ static unsigned long max_alloc_per_card = 32UL * 1024UL * 1024UL;
module_param(max_alloc_per_card, ulong, 0644);
MODULE_PARM_DESC(max_alloc_per_card, "Max total allocation bytes per card.");
+static void __update_allocated_size(struct snd_card *card, ssize_t bytes)
Missing inline ? May be also used for
+static void update_allocated_size(struct snd_card *card, ssize_t bytes)
+static void decrease_allocated_size(struct snd_card *card, size_t bytes)
The rest is fine in my eyes.
Reviewed-by: Jaroslav Kysela <perex@xxxxxxxx>
Thanks,
Jaroslav
--
Jaroslav Kysela <perex@xxxxxxxx>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
