mm-page_alloc-treat-rt-tasks-similar-to-__gfp_high.patch removed from -mm tree

The quilt patch titled
Subject: mm/page_alloc: treat RT tasks similar to __GFP_HIGH
has been removed from the -mm tree. Its filename was
mm-page_alloc-treat-rt-tasks-similar-to-__gfp_high.patch

This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Mel Gorman <[email protected]>
Subject: mm/page_alloc: treat RT tasks similar to __GFP_HIGH
Date: Fri, 13 Jan 2023 11:12:13 +0000

RT tasks are allowed to dip below the min reserve but ALLOC_HARDER is typically combined with ALLOC_MIN_RESERVE so RT tasks are a little unusual. While there is some justification for allowing RT tasks access to memory reserves, there is a strong chance that a RT task that is also under memory pressure is at risk of missing deadlines anyway. Relax how much reserves an RT task can access by treating it the same as __GFP_HIGH allocations.

Note that in a future kernel release that the RT special casing will be removed. Hard realtime tasks should be locking down resources in advance and ensuring enough memory is available. Even a soft-realtime task like audio or video live decoding which cannot jitter should be allocating both memory and any disk space required up-front before the recording starts instead of relying on reserves. At best, reserve access will only delay the problem by a very short interval.

---

@@ -4865,7 +4865,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
 		 */
 		alloc_flags &= ~ALLOC_CPUSET;
 	} else if (unlikely(rt_task(current)) && in_task())
-		alloc_flags |= ALLOC_HARDER;
+		alloc_flags |= ALLOC_MIN_RESERVE;
 
 	alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags);
 

_

Patches currently in -mm which might be from [email protected] are