1 /* $NetBSD: shrinker.h,v 1.5 2021/12/19 01:22:37 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2013 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Taylor R. Campbell. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #ifndef _LINUX_SHRINKER_H_ 33 #define _LINUX_SHRINKER_H_ 34 35 #include <uvm/uvm.h> 36 37 struct shrink_control { 38 unsigned long nr_to_scan; 39 unsigned long nr_scanned; 40 }; 41 42 struct shrinker { 43 int (*shrink)(struct shrinker *, struct shrink_control *); 44 unsigned long (*count_objects)(struct shrinker *, 45 struct shrink_control *); 46 unsigned long (*scan_objects)(struct shrinker *, 47 struct shrink_control *); 48 int seeks; 49 size_t batch; 50 }; 51 52 #define SHRINK_STOP (~0UL) 53 54 #define DEFAULT_SEEKS 2 /* XXX cargo-culted from Linux */ 55 56 static inline int 57 register_shrinker(struct shrinker *shrinker __unused) 58 { 59 return 0; 60 } 61 62 static inline void 63 unregister_shrinker(struct shrinker *shrinker __unused) 64 { 65 } 66 67 static inline bool 68 current_is_kswapd(void) 69 { 70 return curlwp == uvm.pagedaemon_lwp; 71 } 72 73 static inline size_t 74 get_nr_swap_pages(void) 75 { 76 return uvmexp.swpages; 77 } 78 79 #endif /* _LINUX_SHRINKER_H_ */ 80