On 11/01/2021 13:43, Ahmed S. Darwish wrote:
Hi John, Jason,
On Tue, Dec 22, 2020 at 12:54:58PM +0000, John Garry wrote:
On 22/12/2020 12:30, Jason Yan wrote:
return event;
So default for phy->ha->event_thres is 32, and I can't imagine that
The default value is 1024.
Ah, 32 is the minimum allowed set via sysfs.
anyone has ever reconfigured this via sysfs or even required a value
that large. Maybe Jason (cc'ed) knows better. It's an arbitrary
value to say that the PHY is malfunctioning. I do note that there is
the circular path sas_alloc_event() -> sas_notify_phy_event() ->
sas_alloc_event() there also.
Anyway, if the 32x event memories were per-allocated, maybe there is
a clean method to manage this memory, which even works in atomic
context, so we could avoid this rework (ignoring the context bugs
you reported for a moment). I do also note that the sas_event_cache
size is not huge.
Pre-allocated memory is an option.(Which we have tried at the very
beginnig by Wang Yijing.)
Right, I remember this, but I think the concern was having a proper method
to manage this pre-allocated memory then. And same problem now.
Or directly use GFP_ATOMIC is maybe better than passing flags from lldds.
I think that if we don't really need this, then should not use it.
Kind reminder. Do we have any consensus here?
Hi Ahmed,
To me, what you're doing seems fine.
I was looking for some API to manage small memory pools and which is
atomic safe to avoid passing the context flag, but I didn't find such a
thing.
Just one other thing to mention:
I have a patch to remove the indirection in libsas notifiers:
https://github.com/hisilicon/kernel-dev/commit/87fcd7e113dc05b7933260e7fa4588dc3730cc2a
I was going to send it today. Hopefully, if community has no problem
with it, you can make your changes with that in mind.
Thanks,
John
