Author: kib
Date: Mon Aug 27 09:39:34 2018
New Revision: 338335
URL: https://svnweb.freebsd.org/changeset/base/338335
Log:
MFC r337714:
Prevent some parallel swap-ins, rate-limit swapper swap-ins.
Modified:
stable/11/sys/vm/vm_swapout.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/vm/vm_swapout.c
==============================================================================
--- stable/11/sys/vm/vm_swapout.c Mon Aug 27 07:32:41 2018
(r338334)
+++ stable/11/sys/vm/vm_swapout.c Mon Aug 27 09:39:34 2018
(r338335)
@@ -157,6 +157,8 @@ static struct mtx vm_daemon_mtx;
MTX_SYSINIT(vm_daemon, &vm_daemon_mtx, "vm daemon", MTX_DEF);
static int swapped_cnt;
+static int swap_inprogress; /* Pending swap-ins done outside swapper. */
+static int last_swapin;
static void swapclear(struct proc *);
static int swapout(struct proc *);
@@ -625,6 +627,8 @@ faultin(struct proc *p)
sx_xlock(&allproc_lock);
MPASS(swapped_cnt > 0);
swapped_cnt--;
+ if (curthread != &thread0)
+ swap_inprogress++;
sx_xunlock(&allproc_lock);
/*
@@ -635,6 +639,13 @@ faultin(struct proc *p)
FOREACH_THREAD_IN_PROC(p, td)
vm_thread_swapin(td, oom_alloc);
+ if (curthread != &thread0) {
+ sx_xlock(&allproc_lock);
+ MPASS(swap_inprogress > 0);
+ swap_inprogress--;
+ last_swapin = ticks;
+ sx_xunlock(&allproc_lock);
+ }
PROC_LOCK(p);
swapclear(p);
p->p_swtick = ticks;
@@ -652,18 +663,17 @@ faultin(struct proc *p)
*/
static struct proc *
-swapper_selector(void)
+swapper_selector(bool wkilled_only)
{
struct proc *p, *res;
struct thread *td;
- int min_flag, ppri, pri, slptime, swtime;
+ int ppri, pri, slptime, swtime;
sx_assert(&allproc_lock, SA_SLOCKED);
if (swapped_cnt == 0)
return (NULL);
res = NULL;
ppri = INT_MIN;
- min_flag = vm_page_count_min();
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
if (p->p_state == PRS_NEW || (p->p_flag & (P_SWAPPINGOUT |
@@ -681,7 +691,7 @@ swapper_selector(void)
*/
return (p);
}
- if (min_flag) {
+ if (wkilled_only) {
PROC_UNLOCK(p);
continue;
}
@@ -712,11 +722,29 @@ swapper_selector(void)
}
PROC_UNLOCK(p);
}
+
if (res != NULL)
PROC_LOCK(res);
return (res);
}
+#define SWAPIN_INTERVAL (MAXSLP * hz / 2)
+
+/*
+ * Limit swapper to swap in one non-WKILLED process in MAXSLP/2
+ * interval, assuming that there is:
+ * - no memory shortage;
+ * - no parallel swap-ins;
+ * - no other swap-ins in the current SWAPIN_INTERVAL.
+ */
+static bool
+swapper_wkilled_only(void)
+{
+
+ return (vm_page_count_min() || swap_inprogress > 0 ||
+ (u_int)(ticks - last_swapin) < SWAPIN_INTERVAL);
+}
+
void
swapper(void)
{
@@ -724,11 +752,11 @@ swapper(void)
for (;;) {
sx_slock(&allproc_lock);
- p = swapper_selector();
+ p = swapper_selector(swapper_wkilled_only());
sx_sunlock(&allproc_lock);
if (p == NULL) {
- tsleep(&proc0, PVM, "swapin", MAXSLP * hz / 2);
+ tsleep(&proc0, PVM, "swapin", SWAPIN_INTERVAL);
} else {
PROC_LOCK_ASSERT(p, MA_OWNED);
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