On Fri, Nov 15, 2024 at 05:48:53PM -0800, Alexei Starovoitov wrote:
> +static inline struct page *try_alloc_page_noprof(int nid)
> +{
> + /* If spin_locks are not held and interrupts are enabled, use normal path. */
> + if (preemptible())
> + return alloc_pages_node_noprof(nid, GFP_NOWAIT | __GFP_ZERO, 0);
This isn't right for PREEMPT_RT, spinlock_t will be preemptible, but you
very much do not want regular allocation calls while inside the
allocator itself for example.
> + /*
> + * Best effort allocation from percpu free list.
> + * If it's empty attempt to spin_trylock zone->lock.
> + * Do not specify __GFP_KSWAPD_RECLAIM to avoid wakeup_kswapd
> + * that may need to grab a lock.
> + * Do not specify __GFP_ACCOUNT to avoid local_lock.
> + * Do not warn either.
> + */
> + return alloc_pages_node_noprof(nid, __GFP_TRYLOCK | __GFP_NOWARN | __GFP_ZERO, 0);
> +}
