From: Andrea Arcangeli <aarcange@xxxxxxxxxx> It's unclear why schedule friendly kernel threads can't be taken away by the CPU through the scheduler itself. It's safer to stop them as they can trigger memory allocation, if kswapd also freezes itself to avoid generating I/O they have too. Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx> --- diff --git a/mm/huge_memory.c b/mm/huge_memory.c --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -15,6 +15,7 @@ #include <linux/mm_inline.h> #include <linux/kthread.h> #include <linux/khugepaged.h> +#include <linux/freezer.h> #include <asm/tlb.h> #include <asm/pgalloc.h> #include "internal.h" @@ -2063,6 +2064,9 @@ static void khugepaged_do_scan(struct pa break; #endif + if (unlikely(kthread_should_stop() || freezing(current))) + break; + spin_lock(&khugepaged_mm_lock); if (!khugepaged_scan.mm_slot) pass_through_head++; @@ -2125,6 +2129,9 @@ static void khugepaged_loop(void) if (hpage) put_page(hpage); #endif + try_to_freeze(); + if (unlikely(kthread_should_stop())) + break; if (khugepaged_has_work()) { DEFINE_WAIT(wait); if (!khugepaged_scan_sleep_millisecs) @@ -2135,8 +2142,8 @@ static void khugepaged_loop(void) khugepaged_scan_sleep_millisecs)); remove_wait_queue(&khugepaged_wait, &wait); } else if (khugepaged_enabled()) - wait_event_interruptible(khugepaged_wait, - khugepaged_wait_event()); + wait_event_freezable(khugepaged_wait, + khugepaged_wait_event()); } } @@ -2144,6 +2151,7 @@ static int khugepaged(void *none) { struct mm_slot *mm_slot; + set_freezable(); set_user_nice(current, 19); /* serialize with start_khugepaged() */ @@ -2158,6 +2166,8 @@ static int khugepaged(void *none) mutex_lock(&khugepaged_mutex); if (!khugepaged_enabled()) break; + if (unlikely(kthread_should_stop())) + break; } spin_lock(&khugepaged_mm_lock); diff --git a/mm/ksm.c b/mm/ksm.c --- a/mm/ksm.c +++ b/mm/ksm.c @@ -34,6 +34,7 @@ #include <linux/swap.h> #include <linux/ksm.h> #include <linux/hash.h> +#include <linux/freezer.h> #include <asm/tlbflush.h> #include "internal.h" @@ -1374,7 +1375,7 @@ static void ksm_do_scan(unsigned int sca struct rmap_item *rmap_item; struct page *uninitialized_var(page); - while (scan_npages--) { + while (scan_npages-- && likely(!freezing(current))) { cond_resched(); rmap_item = scan_get_next_rmap_item(&page); if (!rmap_item) @@ -1392,6 +1393,7 @@ static int ksmd_should_run(void) static int ksm_scan_thread(void *nothing) { + set_freezable(); set_user_nice(current, 5); while (!kthread_should_stop()) { @@ -1400,11 +1402,13 @@ static int ksm_scan_thread(void *nothing ksm_do_scan(ksm_thread_pages_to_scan); mutex_unlock(&ksm_thread_mutex); + try_to_freeze(); + if (ksmd_should_run()) { schedule_timeout_interruptible( msecs_to_jiffies(ksm_thread_sleep_millisecs)); } else { - wait_event_interruptible(ksm_thread_wait, + wait_event_freezable(ksm_thread_wait, ksmd_should_run() || kthread_should_stop()); } } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>