diff options
Diffstat (limited to 'sys/amd64/amd64/pmap.c')
| -rw-r--r-- | sys/amd64/amd64/pmap.c | 84 |
1 files changed, 68 insertions, 16 deletions
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index 0c9a2c7..b68ff09 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -934,29 +934,39 @@ retry: return m; } +#ifndef KSTACK_MAX_PAGES +#define KSTACK_MAX_PAGES 32 +#endif + /* * Create the kernel stack (including pcb for i386) for a new thread. * This routine directly affects the fork perf for a process and * create performance for a thread. */ void -pmap_new_thread(struct thread *td) +pmap_new_thread(struct thread *td, int pages) { int i; - vm_page_t ma[KSTACK_PAGES]; + vm_page_t ma[KSTACK_MAX_PAGES]; vm_object_t ksobj; vm_page_t m; vm_offset_t ks; + /* Bounds check */ + if (pages <= 1) + pages = KSTACK_PAGES; + else if (pages > KSTACK_MAX_PAGES) + pages = KSTACK_MAX_PAGES; + /* * allocate object for the kstack */ - ksobj = vm_object_allocate(OBJT_DEFAULT, KSTACK_PAGES); + ksobj = vm_object_allocate(OBJT_DEFAULT, pages); td->td_kstack_obj = ksobj; /* get a kernel virtual address for the kstack for this thread */ #ifdef KSTACK_GUARD - ks = kmem_alloc_nofault(kernel_map, (KSTACK_PAGES + 1) * PAGE_SIZE); + ks = kmem_alloc_nofault(kernel_map, (pages + 1) * PAGE_SIZE); if (ks == 0) panic("pmap_new_thread: kstack allocation failed"); if (*vtopte(ks) != 0) @@ -965,16 +975,22 @@ pmap_new_thread(struct thread *td) td->td_kstack = ks; #else /* get a kernel virtual address for the kstack for this thread */ - ks = kmem_alloc_nofault(kernel_map, KSTACK_PAGES * PAGE_SIZE); + ks = kmem_alloc_nofault(kernel_map, pages * PAGE_SIZE); if (ks == 0) panic("pmap_new_thread: kstack allocation failed"); td->td_kstack = ks; #endif + /* + * Knowing the number of pages allocated is useful when you + * want to deallocate them. + */ + td->td_kstack_pages = pages; + /* * For the length of the stack, link in a real page of ram for each * page of stack. */ - for (i = 0; i < KSTACK_PAGES; i++) { + for (i = 0; i < pages; i++) { /* * Get a kernel stack page */ @@ -986,7 +1002,7 @@ pmap_new_thread(struct thread *td) vm_page_flag_clear(m, PG_ZERO); m->valid = VM_PAGE_BITS_ALL; } - pmap_qenter(ks, ma, KSTACK_PAGES); + pmap_qenter(ks, ma, pages); } /* @@ -998,14 +1014,16 @@ pmap_dispose_thread(td) struct thread *td; { int i; + int pages; vm_object_t ksobj; vm_offset_t ks; vm_page_t m; + pages = td->td_kstack_pages; ksobj = td->td_kstack_obj; ks = td->td_kstack; - pmap_qremove(ks, KSTACK_PAGES); - for (i = 0; i < KSTACK_PAGES; i++) { + pmap_qremove(ks, pages); + for (i = 0; i < pages; i++) { m = vm_page_lookup(ksobj, i); if (m == NULL) panic("pmap_dispose_thread: kstack already missing?"); @@ -1020,14 +1038,44 @@ pmap_dispose_thread(td) * address map. */ #ifdef KSTACK_GUARD - kmem_free(kernel_map, ks - PAGE_SIZE, (KSTACK_PAGES + 1) * PAGE_SIZE); + kmem_free(kernel_map, ks - PAGE_SIZE, (pages + 1) * PAGE_SIZE); #else - kmem_free(kernel_map, ks, KSTACK_PAGES * PAGE_SIZE); + kmem_free(kernel_map, ks, pages * PAGE_SIZE); #endif vm_object_deallocate(ksobj); } /* + * Set up a variable sized alternate kstack. Though it may look MI, it may + * need to be different on certain arches like ia64. + */ +void +pmap_new_altkstack(struct thread *td, int pages) +{ + /* shuffle the original stack */ + td->td_altkstack_obj = td->td_kstack_obj; + td->td_altkstack = td->td_kstack; + td->td_altkstack_pages = td->td_kstack_pages; + + pmap_new_thread(td, pages); +} + +void +pmap_dispose_altkstack(td) + struct thread *td; +{ + pmap_dispose_thread(td); + + /* restore the original kstack */ + 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; +} + +/* * Allow the Kernel stack for a thread to be prejudicially paged out. */ void @@ -1035,14 +1083,16 @@ pmap_swapout_thread(td) struct thread *td; { int i; + int pages; vm_object_t ksobj; vm_offset_t ks; vm_page_t m; + pages = td->td_kstack_pages; ksobj = td->td_kstack_obj; ks = td->td_kstack; - pmap_qremove(ks, KSTACK_PAGES); - for (i = 0; i < KSTACK_PAGES; i++) { + pmap_qremove(ks, pages); + for (i = 0; i < pages; i++) { m = vm_page_lookup(ksobj, i); if (m == NULL) panic("pmap_swapout_thread: kstack already missing?"); @@ -1061,14 +1111,16 @@ pmap_swapin_thread(td) struct thread *td; { int i, rv; - vm_page_t ma[KSTACK_PAGES]; + int pages; + vm_page_t ma[KSTACK_MAX_PAGES]; vm_object_t ksobj; vm_offset_t ks; vm_page_t m; + pages = td->td_kstack_pages; ksobj = td->td_kstack_obj; ks = td->td_kstack; - for (i = 0; i < KSTACK_PAGES; i++) { + for (i = 0; i < pages; i++) { m = vm_page_grab(ksobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); if (m->valid != VM_PAGE_BITS_ALL) { rv = vm_pager_get_pages(ksobj, &m, 1, 0); @@ -1083,7 +1135,7 @@ pmap_swapin_thread(td) vm_page_wakeup(m); vm_page_unlock_queues(); } - pmap_qenter(ks, ma, KSTACK_PAGES); + pmap_qenter(ks, ma, pages); } /*************************************************** |
