From: Michal Hocko <mhocko@xxxxxxxx> 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. Link: http://lkml.kernel.org/r/20170918070834.13083-3-mhocko@xxxxxxxxxx Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx> Cc: Yasuaki Ishimatsu <yasu.isimatu@xxxxxxxxx> Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx> Cc: Igor Mammedov <imammedo@xxxxxxxxxx> Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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 --- a/mm/memory_hotplug.c~mm-memory_hotplug-remove-timeout-from-__offline_memory +++ a/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 */ _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
