[merged] mm-fix-regression-with-deferred-struct-page-init.patch removed from -mm tree

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The patch titled
     Subject: mm/page_alloc.c: fix regression with deferred struct page init
has been removed from the -mm tree.  Its filename was
     mm-fix-regression-with-deferred-struct-page-init.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Juergen Gross <jgross@xxxxxxxx>
Subject: mm/page_alloc.c: fix regression with deferred struct page init

0e56acae4b4dd4a9 ("mm: initialize MAX_ORDER_NR_PAGES at a time instead of
doing larger sections") is causing a regression on some systems when the
kernel is booted as Xen dom0.

The system will just hang in early boot.

Reason is an endless loop in get_page_from_freelist() in case the first
zone looked at has no free memory.  deferred_grow_zone() is always
returning true due to the following code snipplet:

  /* If the zone is empty somebody else may have cleared out the zone */
  if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
                                           first_deferred_pfn)) {
          pgdat->first_deferred_pfn = ULONG_MAX;
          pgdat_resize_unlock(pgdat, &flags);
          return true;
  }

This in turn results in the loop as get_page_from_freelist() is assuming
forward progress can be made by doing some more struct page
initialization.

Link: http://lkml.kernel.org/r/20190620160821.4210-1-jgross@xxxxxxxx
Fixes: 0e56acae4b4dd4a9 ("mm: initialize MAX_ORDER_NR_PAGES at a time instead of doing larger sections")
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Suggested-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Acked-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/page_alloc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/page_alloc.c~mm-fix-regression-with-deferred-struct-page-init
+++ a/mm/page_alloc.c
@@ -1826,7 +1826,8 @@ deferred_grow_zone(struct zone *zone, un
 						 first_deferred_pfn)) {
 		pgdat->first_deferred_pfn = ULONG_MAX;
 		pgdat_resize_unlock(pgdat, &flags);
-		return true;
+		/* Retry only once. */
+		return first_deferred_pfn != ULONG_MAX;
 	}
 
 	/*
_

Patches currently in -mm which might be from jgross@xxxxxxxx are





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