/*- * Copyright (c) 1982, 1986, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)vmmeter.h 8.2 (Berkeley) 7/10/94 * $FreeBSD: src/sys/sys/vmmeter.h,v 1.21.2.2 2002/10/10 19:28:21 dillon Exp $ */ #ifndef _VM_VM_PAGE2_H_ #define _VM_VM_PAGE2_H_ #ifndef _SYS_VMMETER_H_ #include #endif #ifndef _SYS_QUEUE_H_ #include #endif #ifndef _VM_VM_PAGE_H_ #include #endif #ifndef _SYS_SPINLOCK_H_ #include #endif #ifndef _SYS_SPINLOCK2_H_ #include #endif #ifdef _KERNEL /* * Return TRUE if we are under our severe low-free-pages threshold * * This causes user processes to stall to avoid exhausting memory that * the kernel might need. * * reserved < severe < minimum < target < paging_target */ static __inline int vm_page_count_severe(void) { return (vmstats.v_free_severe > vmstats.v_free_count + vmstats.v_cache_count || vmstats.v_free_reserved > vmstats.v_free_count); } /* * Return TRUE if we are under our minimum low-free-pages threshold. * This activates the pageout demon. The pageout demon tries to * reach the target but may stop once it satisfies the minimum. * * reserved < severe < minimum < target < paging_target */ static __inline int vm_page_count_min(int donotcount) { return (vmstats.v_free_min + donotcount > (vmstats.v_free_count + vmstats.v_cache_count) || vmstats.v_free_reserved > vmstats.v_free_count); } /* * Return TRUE if we are under our free page target. The pageout demon * tries to reach the target but may stop once it gets past the min. * * User threads doing normal allocations might wait based on this * function but MUST NOT wait in a loop based on this function as the * VM load may prevent the target from being reached. */ static __inline int vm_page_count_target(void) { return (vmstats.v_free_target > (vmstats.v_free_count + vmstats.v_cache_count) || vmstats.v_free_reserved > vmstats.v_free_count); } /* * Return the number of pages the pageout daemon needs to move into the * cache or free lists. A negative number means we have sufficient free * pages. * * The target free+cache is greater than vm_page_count_target(). The * frontend uses vm_page_count_target() while the backend continue freeing * based on vm_paging_target(). * * This function DOES NOT return TRUE or FALSE. */ static __inline int vm_paging_target(void) { return ( (vmstats.v_free_target + vmstats.v_cache_min) - (vmstats.v_free_count + vmstats.v_cache_count) ); } /* * Return TRUE if hysteresis dictates we should nominally wakeup the * pageout daemon to start working on freeing up some memory. This * routine should NOT be used to determine when to block on the VM system. * We want to wakeup the pageout daemon before we might otherwise block. * * Paging begins when cache+free drops below cache_min + free_min. */ static __inline int vm_paging_needed(void) { if (vmstats.v_free_min + vmstats.v_cache_min > vmstats.v_free_count + vmstats.v_cache_count) { return 1; } if (vmstats.v_free_min > vmstats.v_free_count) return 1; return 0; } static __inline void vm_page_event(vm_page_t m, vm_page_event_t event) { if (m->flags & PG_ACTIONLIST) vm_page_event_internal(m, event); } static __inline void vm_page_init_action(vm_page_t m, vm_page_action_t action, void (*func)(vm_page_t, vm_page_action_t), void *data) { action->m = m; action->func = func; action->data = data; } /* * Clear dirty bits in the VM page but truncate the * end to a DEV_BSIZE'd boundary. * * Used when reading data in, typically via getpages. * The partial device block at the end of the truncation * range should not lose its dirty bit. * * NOTE: This function does not clear the pmap modified bit. */ static __inline void vm_page_clear_dirty_end_nonincl(vm_page_t m, int base, int size) { size = (base + size) & ~DEV_BMASK; if (base < size) vm_page_clear_dirty(m, base, size - base); } /* * Clear dirty bits in the VM page but truncate the * beginning to a DEV_BSIZE'd boundary. * * Used when truncating a buffer. The partial device * block at the beginning of the truncation range * should not lose its dirty bit. * * NOTE: This function does not clear the pmap modified bit. */ static __inline void vm_page_clear_dirty_beg_nonincl(vm_page_t m, int base, int size) { size += base; base = (base + DEV_BMASK) & ~DEV_BMASK; if (base < size) vm_page_clear_dirty(m, base, size - base); } static __inline void vm_page_spin_lock(vm_page_t m) { spin_pool_lock(m); } static __inline void vm_page_spin_unlock(vm_page_t m) { spin_pool_unlock(m); } /* * Wire a vm_page that is already wired. Does not require a busied * page. */ static __inline void vm_page_wire_quick(vm_page_t m) { if (atomic_fetchadd_int(&m->wire_count, 1) == 0) panic("vm_page_wire_quick: wire_count was 0"); } /* * Unwire a vm_page quickly, does not require a busied page. * * This routine refuses to drop the wire_count to 0 and will return * TRUE if it would have had to (instead of decrementing it to 0). * The caller can then busy the page and deal with it. */ static __inline int vm_page_unwire_quick(vm_page_t m) { KKASSERT(m->wire_count > 0); for (;;) { u_int wire_count = m->wire_count; cpu_ccfence(); if (wire_count == 1) return TRUE; if (atomic_cmpset_int(&m->wire_count, wire_count, wire_count - 1)) return FALSE; } } /* * Functions implemented as macros */ static __inline void vm_page_flag_set(vm_page_t m, unsigned int bits) { atomic_set_int(&(m)->flags, bits); } static __inline void vm_page_flag_clear(vm_page_t m, unsigned int bits) { atomic_clear_int(&(m)->flags, bits); } /* * Wakeup anyone waiting for the page after potentially unbusying * (hard or soft) or doing other work on a page that might make a * waiter ready. The setting of PG_WANTED is integrated into the * related flags and it can't be set once the flags are already * clear, so there should be no races here. */ static __inline void vm_page_flash(vm_page_t m) { if (m->flags & PG_WANTED) { vm_page_flag_clear(m, PG_WANTED); wakeup(m); } } /* * Reduce the protection of a page. This routine never raises the * protection and therefore can be safely called if the page is already * at VM_PROT_NONE (it will be a NOP effectively ). * * VM_PROT_NONE will remove all user mappings of a page. This is often * necessary when a page changes state (for example, turns into a copy-on-write * page or needs to be frozen for write I/O) in order to force a fault, or * to force a page's dirty bits to be synchronized and avoid hardware * (modified/accessed) bit update races with pmap changes. * * Since 'prot' is usually a constant, this inline usually winds up optimizing * out the primary conditional. * * WARNING: VM_PROT_NONE can block, but will loop until all mappings have * been cleared. Callers should be aware that other page related elements * might have changed, however. */ static __inline void vm_page_protect(vm_page_t m, int prot) { KKASSERT(m->flags & PG_BUSY); if (prot == VM_PROT_NONE) { if (m->flags & (PG_WRITEABLE|PG_MAPPED)) { pmap_page_protect(m, VM_PROT_NONE); /* PG_WRITEABLE & PG_MAPPED cleared by call */ } } else if ((prot == VM_PROT_READ) && (m->flags & PG_WRITEABLE)) { pmap_page_protect(m, VM_PROT_READ); /* PG_WRITEABLE cleared by call */ } } /* * Zero-fill the specified page. The entire contents of the page will be * zero'd out. */ static __inline boolean_t vm_page_zero_fill(vm_page_t m) { pmap_zero_page(VM_PAGE_TO_PHYS(m)); return (TRUE); } /* * Copy the contents of src_m to dest_m. The pages must be stable but spl * and other protections depend on context. */ static __inline void vm_page_copy(vm_page_t src_m, vm_page_t dest_m) { pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m)); dest_m->valid = VM_PAGE_BITS_ALL; dest_m->dirty = VM_PAGE_BITS_ALL; } /* * Free a page. The page must be marked BUSY. * * Always clear PG_ZERO when freeing a page, which ensures the flag is not * set unless we are absolutely certain the page is zerod. This is * particularly important when the vm_page_alloc*() code moves pages from * PQ_CACHE to PQ_FREE. */ static __inline void vm_page_free(vm_page_t m) { vm_page_flag_clear(m, PG_ZERO); vm_page_free_toq(m); } /* * Free a page to the zerod-pages queue. The caller must ensure that the * page has been zerod. */ static __inline void vm_page_free_zero(vm_page_t m) { #ifdef PMAP_DEBUG #ifdef PHYS_TO_DMAP char *p = (char *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m)); int i; for (i = 0; i < PAGE_SIZE; i++) { if (p[i] != 0) { panic("non-zero page in vm_page_free_zero()"); } } #endif #endif vm_page_flag_set(m, PG_ZERO); vm_page_free_toq(m); } /* * Set page to not be dirty. Note: does not clear pmap modify bits . */ static __inline void vm_page_undirty(vm_page_t m) { m->dirty = 0; } #endif /* _KERNEL */ #endif /* _VM_VM_PAGE2_H_ */