On Fri 26-03-21 14:32:01, Mike Kravetz wrote: [...] > - Just change the mutex to an irq safe spinlock.
Yes please. > AFAICT, the potential > downsides could be: > - Interrupts disabled during long bitmap scans How large those bitmaps are in practice? > - Wasted cpu cycles (spinning) if there is much contention on lock > Both of these would be more of an issue on small/embedded systems. I > took a quick look at the callers of cma_alloc/cma_release and nothing > stood out that could lead to high degrees of contention. However, I > could have missed something. If this is really a practical concern then we can try a more complex solution based on some data. -- Michal Hocko SUSE Labs
