diff options
Diffstat (limited to 'sys/vm/vm_glue.c')
| -rw-r--r-- | sys/vm/vm_glue.c | 138 |
1 files changed, 43 insertions, 95 deletions
diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c index 234cde9..9e43a3f 100644 --- a/sys/vm/vm_glue.c +++ b/sys/vm/vm_glue.c @@ -77,7 +77,6 @@ __FBSDID("$FreeBSD$"); #include <sys/sx.h> #include <sys/sysctl.h> -#include <sys/eventhandler.h> #include <sys/kernel.h> #include <sys/ktr.h> #include <sys/unistd.h> @@ -309,20 +308,6 @@ vm_imgact_unmap_page(struct sf_buf *sf) vm_page_unlock_queues(); } -struct kstack_cache_entry { - vm_object_t ksobj; - struct kstack_cache_entry *next_ks_entry; -}; - -static struct kstack_cache_entry *kstack_cache; -static int kstack_cache_size = 128; -static int kstacks; -static struct mtx kstack_cache_mtx; -SYSCTL_INT(_vm, OID_AUTO, kstack_cache_size, CTLFLAG_RW, &kstack_cache_size, 0, - ""); -SYSCTL_INT(_vm, OID_AUTO, kstacks, CTLFLAG_RD, &kstacks, 0, - ""); - #ifndef KSTACK_MAX_PAGES #define KSTACK_MAX_PAGES 32 #endif @@ -338,7 +323,6 @@ vm_thread_new(struct thread *td, int pages) vm_object_t ksobj; vm_offset_t ks; vm_page_t m, ma[KSTACK_MAX_PAGES]; - struct kstack_cache_entry *ks_ce; int i; /* Bounds check */ @@ -346,22 +330,6 @@ vm_thread_new(struct thread *td, int pages) pages = KSTACK_PAGES; else if (pages > KSTACK_MAX_PAGES) pages = KSTACK_MAX_PAGES; - - if (pages == KSTACK_PAGES) { - mtx_lock(&kstack_cache_mtx); - if (kstack_cache != NULL) { - ks_ce = kstack_cache; - kstack_cache = ks_ce->next_ks_entry; - mtx_unlock(&kstack_cache_mtx); - - td->td_kstack_obj = ks_ce->ksobj; - td->td_kstack = (vm_offset_t)ks_ce; - td->td_kstack_pages = KSTACK_PAGES; - return (1); - } - mtx_unlock(&kstack_cache_mtx); - } - /* * Allocate an object for the kstack. */ @@ -377,8 +345,7 @@ vm_thread_new(struct thread *td, int pages) vm_object_deallocate(ksobj); return (0); } - - atomic_add_int(&kstacks, 1); + if (KSTACK_GUARD_PAGES != 0) { pmap_qremove(ks, KSTACK_GUARD_PAGES); ks += KSTACK_GUARD_PAGES * PAGE_SIZE; @@ -409,13 +376,20 @@ vm_thread_new(struct thread *td, int pages) return (1); } -static void -vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages) +/* + * Dispose of a thread's kernel stack. + */ +void +vm_thread_dispose(struct thread *td) { + vm_object_t ksobj; + vm_offset_t ks; vm_page_t m; - int i; + int i, pages; - atomic_add_int(&kstacks, -1); + pages = td->td_kstack_pages; + ksobj = td->td_kstack_obj; + ks = td->td_kstack; pmap_qremove(ks, pages); VM_OBJECT_LOCK(ksobj); for (i = 0; i < pages; i++) { @@ -431,66 +405,9 @@ vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages) vm_object_deallocate(ksobj); kmem_free(kernel_map, ks - (KSTACK_GUARD_PAGES * PAGE_SIZE), (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); -} - -/* - * Dispose of a thread's kernel stack. - */ -void -vm_thread_dispose(struct thread *td) -{ - vm_object_t ksobj; - vm_offset_t ks; - struct kstack_cache_entry *ks_ce; - int pages; - - pages = td->td_kstack_pages; - ksobj = td->td_kstack_obj; - ks = td->td_kstack; - if (pages == KSTACK_PAGES && kstacks <= kstack_cache_size) { - ks_ce = (struct kstack_cache_entry *)ks; - ks_ce->ksobj = ksobj; - mtx_lock(&kstack_cache_mtx); - ks_ce->next_ks_entry = ks_ce; - kstack_cache = ks_ce; - mtx_unlock(&kstack_cache_mtx); - return; - } - vm_thread_stack_dispose(ksobj, ks, pages); td->td_kstack = 0; - td->td_kstack_pages = 0; } -static void -vm_thread_stack_lowmem(void *nulll) -{ - struct kstack_cache_entry *ks_ce, *ks_ce1; - - mtx_lock(&kstack_cache_mtx); - ks_ce = kstack_cache; - kstack_cache = NULL; - mtx_unlock(&kstack_cache_mtx); - - while (ks_ce != NULL) { - ks_ce1 = ks_ce; - ks_ce = ks_ce->next_ks_entry; - - vm_thread_stack_dispose(ks_ce1->ksobj, (vm_offset_t)ks_ce1, - KSTACK_PAGES); - } -} - -static void -kstack_cache_init(void *nulll) -{ - - EVENTHANDLER_REGISTER(vm_lowmem, vm_thread_stack_lowmem, NULL, - EVENTHANDLER_PRI_ANY); -} - -MTX_SYSINIT(kstack_cache, &kstack_cache_mtx, "kstkch", MTX_DEF); -SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL); - /* * Allow a thread's kernel stack to be paged out. */ @@ -551,6 +468,37 @@ vm_thread_swapin(struct thread *td) } /* + * Set up a variable-sized alternate kstack. + */ +int +vm_thread_new_altkstack(struct thread *td, int pages) +{ + + td->td_altkstack = td->td_kstack; + td->td_altkstack_obj = td->td_kstack_obj; + td->td_altkstack_pages = td->td_kstack_pages; + + return (vm_thread_new(td, pages)); +} + +/* + * Restore the original kstack. + */ +void +vm_thread_dispose_altkstack(struct thread *td) +{ + + vm_thread_dispose(td); + + td->td_kstack = td->td_altkstack; + td->td_kstack_obj = td->td_altkstack_obj; + td->td_kstack_pages = td->td_altkstack_pages; + td->td_altkstack = 0; + td->td_altkstack_obj = NULL; + td->td_altkstack_pages = 0; +} + +/* * Implement fork's actions on an address space. * Here we arrange for the address space to be copied or referenced, * allocate a user struct (pcb and kernel stack), then call the |
