mm-memory_hotplug-remove-timeout-from-__offline_memory.patch removed from -mm tree

The patch titled
Subject: mm, memory_hotplug: remove timeout from __offline_memory
has been removed from the -mm tree. Its filename was
mm-memory_hotplug-remove-timeout-from-__offline_memory.patch

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

------------------------------------------------------
From: Michal Hocko <[email protected]>
Subject: mm, memory_hotplug: remove timeout from __offline_memory

We have a hardcoded 120s timeout after which the memory offline fails basically since the hot remove has been introduced. This is essentially a policy implemented in the kernel. Moreover there is no way to adjust the timeout and so we are sometimes facing memory offline failures if the system is under a heavy memory pressure or very intensive CPU workload on large machines.

It is not very clear what purpose the timeout actually serves. The offline operation is interruptible by a signal so if userspace wants some timeout based termination this can be done trivially by sending a signal.

If there is a strong usecase to do this from the kernel then we should do it properly and have a it tunable from the userspace with the timeout disabled by default along with the explanation who uses it and for what purporse.

---

 mm/memory_hotplug.c |   10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff -puN mm/memory_hotplug.c~mm-memory_hotplug-remove-timeout-from-__offline_memory mm/memory_hotplug.c
@@ -1590,9 +1590,9 @@ static void node_states_clear_node(int n
 }
 
 static int __ref __offline_pages(unsigned long start_pfn,
-		  unsigned long end_pfn, unsigned long timeout)
+		  unsigned long end_pfn)
 {
-	unsigned long pfn, nr_pages, expire;
+	unsigned long pfn, nr_pages;
 	long offlined_pages;
 	int ret, node;
 	unsigned long flags;

@@ -1630,12 +1630,8 @@ static int __ref __offline_pages(unsigne
 		goto failed_removal;
 
 	pfn = start_pfn;
-	expire = jiffies + timeout;
 repeat:
 	/* start memory hot removal */
-	ret = -EBUSY;
-	if (time_after(jiffies, expire))
-		goto failed_removal;
 	ret = -EINTR;
 	if (signal_pending(current))
 		goto failed_removal;

@@ -1708,7 +1704,7 @@ failed_removal:
 /* Must be protected by mem_hotplug_begin() or a device_lock */
 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
 {
-	return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
+	return __offline_pages(start_pfn, start_pfn + nr_pages);
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 

_

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

mm-memory_hotplug-do-not-back-off-draining-pcp-free-pages-from-kworker-context.patch mm-hugetlb-drop-hugepages_treat_as_movable-sysctl.patch