diff options
Diffstat (limited to 'sys/vm/vm_swapout.c')
-rw-r--r-- | sys/vm/vm_swapout.c | 127 |
1 files changed, 81 insertions, 46 deletions
diff --git a/sys/vm/vm_swapout.c b/sys/vm/vm_swapout.c index d4e6e3a86770..343ff830f0c6 100644 --- a/sys/vm/vm_swapout.c +++ b/sys/vm/vm_swapout.c @@ -158,13 +158,14 @@ static struct mtx vm_daemon_mtx; /* Allow for use by vm_pageout before vm_daemon is initialized. */ MTX_SYSINIT(vm_daemon, &vm_daemon_mtx, "vm daemon", MTX_DEF); +static int swapped_cnt; + static void swapclear(struct proc *); static int swapout(struct proc *); static void vm_swapout_map_deactivate_pages(vm_map_t, long); static void vm_swapout_object_deactivate_pages(pmap_t, vm_object_t, long); static void swapout_procs(int action); static void vm_req_vmdaemon(int req); -static void vm_thread_swapin(struct thread *td); static void vm_thread_swapout(struct thread *td); /* @@ -563,7 +564,7 @@ vm_thread_swapout(struct thread *td) * Bring the kernel stack for a specified thread back in. */ static void -vm_thread_swapin(struct thread *td) +vm_thread_swapin(struct thread *td, int oom_alloc) { vm_object_t ksobj; vm_page_t ma[KSTACK_MAX_PAGES]; @@ -572,7 +573,7 @@ vm_thread_swapin(struct thread *td) pages = td->td_kstack_pages; ksobj = td->td_kstack_obj; VM_OBJECT_WLOCK(ksobj); - (void)vm_page_grab_pages(ksobj, 0, VM_ALLOC_NORMAL | VM_ALLOC_WIRED, ma, + (void)vm_page_grab_pages(ksobj, 0, oom_alloc | VM_ALLOC_WIRED, ma, pages); for (i = 0; i < pages;) { vm_page_assert_xbusied(ma[i]); @@ -605,8 +606,10 @@ void faultin(struct proc *p) { struct thread *td; + int oom_alloc; PROC_LOCK_ASSERT(p, MA_OWNED); + /* * If another process is swapping in this process, * just wait until it finishes. @@ -616,7 +619,11 @@ faultin(struct proc *p) msleep(&p->p_flag, &p->p_mtx, PVM, "faultin", 0); return; } + if ((p->p_flag & P_INMEM) == 0) { + oom_alloc = (p->p_flag & P_WKILLED) != 0 ? VM_ALLOC_SYSTEM : + VM_ALLOC_NORMAL; + /* * Don't let another thread swap process p out while we are * busy swapping it in. @@ -624,6 +631,10 @@ faultin(struct proc *p) ++p->p_lock; p->p_flag |= P_SWAPPINGIN; PROC_UNLOCK(p); + sx_xlock(&allproc_lock); + MPASS(swapped_cnt > 0); + swapped_cnt--; + sx_xunlock(&allproc_lock); /* * We hold no lock here because the list of threads @@ -631,14 +642,14 @@ faultin(struct proc *p) * swapped out. */ FOREACH_THREAD_IN_PROC(p, td) - vm_thread_swapin(td); + vm_thread_swapin(td, oom_alloc); + PROC_LOCK(p); swapclear(p); p->p_swtick = ticks; - wakeup(&p->p_flag); - /* Allow other threads to swap p out now. */ + wakeup(&p->p_flag); --p->p_lock; } } @@ -648,26 +659,38 @@ faultin(struct proc *p) * is enough space for them. Of course, if a process waits for a long * time, it will be swapped in anyway. */ -void -swapper(void) + +static struct proc * +swapper_selector(void) { - struct proc *p, *pp; + struct proc *p, *res; struct thread *td; - int ppri, pri, slptime, swtime; - -loop: - if (vm_page_count_min()) { - vm_wait_min(); - goto loop; - } + int min_flag, ppri, pri, slptime, swtime; - pp = NULL; + sx_assert(&allproc_lock, SA_SLOCKED); + if (swapped_cnt == 0) + return (NULL); + res = NULL; ppri = INT_MIN; - sx_slock(&allproc_lock); + 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 | P_SWAPPINGIN | P_INMEM)) { + if (p->p_state == PRS_NEW || (p->p_flag & (P_SWAPPINGOUT | + P_SWAPPINGIN | P_INMEM)) != 0) { + PROC_UNLOCK(p); + continue; + } + if (p->p_state == PRS_NORMAL && (p->p_flag & P_WKILLED) != 0) { + /* + * A swapped-out process might have mapped a + * large portion of the system's pages as + * anonymous memory. There is no other way to + * release the memory other than to kill the + * process, for which we need to swap it in. + */ + return (p); + } + if (min_flag) { PROC_UNLOCK(p); continue; } @@ -690,7 +713,7 @@ loop: * selection. */ if (pri > ppri) { - pp = p; + res = p; ppri = pri; } } @@ -698,33 +721,40 @@ loop: } PROC_UNLOCK(p); } - sx_sunlock(&allproc_lock); + if (res != NULL) + PROC_LOCK(res); + return (res); +} - /* - * Nothing to do, back to sleep. - */ - if ((p = pp) == NULL) { - tsleep(&proc0, PVM, "swapin", MAXSLP * hz / 2); - goto loop; - } - PROC_LOCK(p); +void +swapper(void) +{ + struct proc *p; - /* - * Another process may be bringing or may have already - * brought this process in while we traverse all threads. - * Or, this process may even be being swapped out again. - */ - if (p->p_flag & (P_INMEM | P_SWAPPINGOUT | P_SWAPPINGIN)) { - PROC_UNLOCK(p); - goto loop; - } + for (;;) { + sx_slock(&allproc_lock); + p = swapper_selector(); + sx_sunlock(&allproc_lock); - /* - * We would like to bring someone in. - */ - faultin(p); - PROC_UNLOCK(p); - goto loop; + if (p == NULL) { + tsleep(&proc0, PVM, "swapin", MAXSLP * hz / 2); + } else { + PROC_LOCK_ASSERT(p, MA_OWNED); + + /* + * Another process may be bringing or may have + * already brought this process in while we + * traverse all threads. Or, this process may + * have exited or even being swapped out + * again. + */ + if (p->p_state == PRS_NORMAL && (p->p_flag & (P_INMEM | + P_SWAPPINGOUT | P_SWAPPINGIN)) == 0) { + faultin(p); + } + PROC_UNLOCK(p); + } + } } /* @@ -803,7 +833,12 @@ swapout_procs(int action) didswap = true; PROC_UNLOCK(p); - sx_slock(&allproc_lock); + if (didswap) { + sx_xlock(&allproc_lock); + swapped_cnt++; + sx_downgrade(&allproc_lock); + } else + sx_slock(&allproc_lock); PRELE(p); } sx_sunlock(&allproc_lock); |