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Index: head/sys/vm/vm_swapout.c
===================================================================
--- head/sys/vm/vm_swapout.c
+++ head/sys/vm/vm_swapout.c
@@ -734,126 +734,73 @@
struct proc *p;
struct thread *td;
int slptime;
- bool didswap;
+ bool didswap, doswap;
+ MPASS((action & (VM_SWAP_NORMAL | VM_SWAP_IDLE)) != 0);
+
didswap = false;
-retry:
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
- PROC_LOCK(p);
/*
- * Watch out for a process in
- * creation. It may have no
- * address space or lock yet.
+ * Filter out not yet fully constructed processes. Do
+ * not swap out held processes. Avoid processes which
+ * are system, exiting, execing, traced, already swapped
+ * out or are in the process of being swapped in or out.
*/
- if (p->p_state == PRS_NEW) {
+ PROC_LOCK(p);
+ if (p->p_state != PRS_NORMAL || p->p_lock != 0 || (p->p_flag &
+ (P_SYSTEM | P_WEXIT | P_INEXEC | P_STOPPED_SINGLE |
+ P_TRACED | P_SWAPPINGOUT | P_SWAPPINGIN | P_INMEM)) !=
+ P_INMEM) {
PROC_UNLOCK(p);
continue;
}
+
/*
- * An aio daemon switches its
- * address space while running.
- * Perform a quick check whether
- * a process has P_SYSTEM.
- * Filter out exiting processes.
+ * Further consideration of this process for swap out
+ * requires iterating over its threads. We release
+ * allproc_lock here so that process creation and
+ * destruction are not blocked while we iterate.
+ *
+ * To later reacquire allproc_lock and resume
+ * iteration over the allproc list, we will first have
+ * to release the lock on the process. We place a
+ * hold on the process so that it remains in the
+ * allproc list while it is unlocked.
*/
- if ((p->p_flag & (P_SYSTEM | P_WEXIT)) != 0) {
- PROC_UNLOCK(p);
- continue;
- }
_PHOLD_LITE(p);
- PROC_UNLOCK(p);
sx_sunlock(&allproc_lock);
- PROC_LOCK(p);
- if (p->p_lock != 1 || (p->p_flag & (P_STOPPED_SINGLE |
- P_TRACED | P_SYSTEM)) != 0)
- goto nextproc;
-
/*
- * Only aiod changes vmspace. However, it will be
- * skipped because of the if statement above checking
- * for P_SYSTEM.
+ * Do not swapout a realtime process.
+ * Guarantee swap_idle_threshold1 time in memory.
+ * If the system is under memory stress, or if we are
+ * swapping idle processes >= swap_idle_threshold2,
+ * then swap the process out.
*/
- if ((p->p_flag & (P_INMEM | P_SWAPPINGOUT | P_SWAPPINGIN)) !=
- P_INMEM)
- goto nextproc;
-
- switch (p->p_state) {
- default:
- /*
- * Don't swap out processes in any sort
- * of 'special' state.
- */
- break;
-
- case PRS_NORMAL:
- /*
- * do not swapout a realtime process
- * Check all the thread groups..
- */
- FOREACH_THREAD_IN_PROC(p, td) {
- thread_lock(td);
- if (PRI_IS_REALTIME(td->td_pri_class)) {
- thread_unlock(td);
- goto nextproc;
- }
- slptime = (ticks - td->td_slptick) / hz;
- /*
- * Guarantee swap_idle_threshold1
- * time in memory.
- */
- if (slptime < swap_idle_threshold1) {
- thread_unlock(td);
- goto nextproc;
- }
-
- /*
- * Do not swapout a process if it is
- * waiting on a critical event of some
- * kind or there is a thread whose
- * pageable memory may be accessed.
- *
- * This could be refined to support
- * swapping out a thread.
- */
- if (!thread_safetoswapout(td)) {
- thread_unlock(td);
- goto nextproc;
- }
- /*
- * If the system is under memory stress,
- * or if we are swapping
- * idle processes >= swap_idle_threshold2,
- * then swap the process out.
- */
- if ((action & VM_SWAP_NORMAL) == 0 &&
- ((action & VM_SWAP_IDLE) == 0 ||
- slptime < swap_idle_threshold2)) {
- thread_unlock(td);
- goto nextproc;
- }
-
- thread_unlock(td);
- }
-
- /*
- * If the pageout daemon didn't free enough pages,
- * or if this process is idle and the system is
- * configured to swap proactively, swap it out.
- */
- _PRELE(p);
- if (swapout(p) == 0)
- didswap = true;
- PROC_UNLOCK(p);
- goto retry;
+ doswap = true;
+ FOREACH_THREAD_IN_PROC(p, td) {
+ thread_lock(td);
+ slptime = (ticks - td->td_slptick) / hz;
+ if (PRI_IS_REALTIME(td->td_pri_class) ||
+ slptime < swap_idle_threshold1 ||
+ !thread_safetoswapout(td) ||
+ ((action & VM_SWAP_NORMAL) == 0 &&
+ slptime < swap_idle_threshold2))
+ doswap = false;
+ thread_unlock(td);
+ if (!doswap)
+ break;
}
-nextproc:
+ if (doswap && swapout(p) == 0)
+ didswap = true;
+
PROC_UNLOCK(p);
sx_slock(&allproc_lock);
PRELE(p);
}
sx_sunlock(&allproc_lock);
+
/*
* If we swapped something out, and another process needed memory,
* then wakeup the sched process.

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