The patch titled
ksm: keep quiet while list empty
has been added to the -mm tree. Its filename is
ksm-keep-quiet-while-list-empty.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: ksm: keep quiet while list empty
From: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
ksm_scan_thread already sleeps in wait_event_interruptible until setting
ksm_run activates it; but if there's nothing on its list to look at, i.e.
nobody has yet said madvise MADV_MERGEABLE, it's a shame to be clocking
up system time and full_scans: ksmd_should_run added to check that too.
And move the mutex_lock out around it: the new counts showed that when
ksm_run is stopped, a little work often got done afterwards, because it
had been read before taking the mutex.
Signed-off-by: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Acked-by: Izik Eidus <ieidus@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/ksm.c | 28 ++++++++++++++++++++++------
1 file changed, 22 insertions(+), 6 deletions(-)
diff -puN mm/ksm.c~ksm-keep-quiet-while-list-empty mm/ksm.c
--- a/mm/ksm.c~ksm-keep-quiet-while-list-empty
+++ a/mm/ksm.c
@@ -1287,21 +1287,27 @@ static void ksm_do_scan(unsigned int sca
}
}
+static int ksmd_should_run(void)
+{
+ return (ksm_run & KSM_RUN_MERGE) && !list_empty(&ksm_mm_head.mm_list);
+}
+
static int ksm_scan_thread(void *nothing)
{
set_user_nice(current, 5);
while (!kthread_should_stop()) {
- if (ksm_run & KSM_RUN_MERGE) {
- mutex_lock(&ksm_thread_mutex);
+ mutex_lock(&ksm_thread_mutex);
+ if (ksmd_should_run())
ksm_do_scan(ksm_thread_pages_to_scan);
- mutex_unlock(&ksm_thread_mutex);
+ mutex_unlock(&ksm_thread_mutex);
+
+ if (ksmd_should_run()) {
schedule_timeout_interruptible(
msecs_to_jiffies(ksm_thread_sleep_millisecs));
} else {
wait_event_interruptible(ksm_thread_wait,
- (ksm_run & KSM_RUN_MERGE) ||
- kthread_should_stop());
+ ksmd_should_run() || kthread_should_stop());
}
}
return 0;
@@ -1346,10 +1352,16 @@ int ksm_madvise(struct vm_area_struct *v
int __ksm_enter(struct mm_struct *mm)
{
- struct mm_slot *mm_slot = alloc_mm_slot();
+ struct mm_slot *mm_slot;
+ int needs_wakeup;
+
+ mm_slot = alloc_mm_slot();
if (!mm_slot)
return -ENOMEM;
+ /* Check ksm_run too? Would need tighter locking */
+ needs_wakeup = list_empty(&ksm_mm_head.mm_list);
+
spin_lock(&ksm_mmlist_lock);
insert_to_mm_slots_hash(mm, mm_slot);
/*
@@ -1361,6 +1373,10 @@ int __ksm_enter(struct mm_struct *mm)
spin_unlock(&ksm_mmlist_lock);
set_bit(MMF_VM_MERGEABLE, &mm->flags);
+
+ if (needs_wakeup)
+ wake_up_interruptible(&ksm_thread_wait);
+
return 0;
}
_
Patches currently in -mm which might be from hugh.dickins@xxxxxxxxxxxxx are
acpi-fix-null-bug-for-hid-uid-string.patch
mm-oom-analysis-add-shmem-vmstat.patch
ksm-add-mmu_notifier-set_pte_at_notify.patch
ksm-first-tidy-up-madvise_vma.patch
ksm-define-madv_mergeable-and-madv_unmergeable.patch
ksm-the-mm-interface-to-ksm.patch
ksm-no-debug-in-page_dup_rmap.patch
ksm-identify-pageksm-pages.patch
ksm-kernel-samepage-merging.patch
ksm-prevent-mremap-move-poisoning.patch
ksm-change-copyright-message.patch
ksm-change-ksm-nice-level-to-be-5.patch
ksm-rename-kernel_pages_allocated.patch
ksm-move-pages_sharing-updates.patch
ksm-pages_unshared-and-pages_volatile.patch
ksm-break-cow-once-unshared.patch
ksm-keep-quiet-while-list-empty.patch
ksm-five-little-cleanups.patch
ksm-fix-endless-loop-on-oom.patch
ksm-distribute-remove_mm_from_lists.patch
ksm-fix-oom-deadlock.patch
ksm-sysfs-and-defaults.patch
ksm-add-some-documentation.patch
ksm-remove-vm_mergeable_flags.patch
getrusage-fill-ru_maxrss-value.patch
getrusage-fill-ru_maxrss-value-update.patch
ramfs-move-ramfs_magic-to-include-linux-magich.patch
memory-controller-soft-limit-organize-cgroups-v9-fix.patch
prio_tree-debugging-patch.patch
--
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
