timestamp empty pages, and only free them if theyve been idle for at least

a second.

this basically brings back the functionality that was trimmed in r1.53,
except this version uses ticks instead of very slow hardware clock reads.

ok tedu@

diff --git a/sys/kern/subr_pool.c b/sys/kern/subr_pool.c
index 1cedfa6..d8866a5 100644 (file)
--- a/sys/kern/subr_pool.c
+++ b/sys/kern/subr_pool.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: subr_pool.c,v 1.171 2014/12/19 02:46:47 dlg Exp $     */
+/*     $OpenBSD: subr_pool.c,v 1.172 2014/12/19 02:49:07 dlg Exp $     */
 /*     $NetBSD: subr_pool.c,v 1.61 2001/09/26 07:14:56 chs Exp $       */
 
 /*-
@@ -82,6 +82,7 @@ struct pool_item_header {
        int                     ph_nmissing;    /* # of chunks in use */
        caddr_t                 ph_page;        /* this page's address */
        u_long                  ph_magic;
+       int                     ph_tick;
 };
 #define POOL_MAGICBIT (1 << 3) /* keep away from perturbed low bits */
 #define POOL_PHPOISON(ph) ISSET((ph)->ph_magic, POOL_MAGICBIT)
@@ -620,6 +621,7 @@ pool_put(struct pool *pp, void *v)
 {
        struct pool_item *pi = v;
        struct pool_item_header *ph, *freeph = NULL;
+       extern int ticks;
 
 #ifdef DIAGNOSTIC
        if (v == NULL)
@@ -664,6 +666,7 @@ pool_put(struct pool *pp, void *v)
                 */
                pp->pr_nidle++;
 
+               ph->ph_tick = ticks;
                TAILQ_REMOVE(&pp->pr_partpages, ph, ph_pagelist);
                TAILQ_INSERT_TAIL(&pp->pr_emptypages, ph, ph_pagelist);
                pool_update_curpage(pp);
@@ -674,8 +677,11 @@ pool_put(struct pool *pp, void *v)
 
        /* is it time to free a page? */
        if (pp->pr_nidle > pp->pr_maxpages &&
-           (freeph = TAILQ_FIRST(&pp->pr_emptypages)) != NULL)
+           (ph = TAILQ_FIRST(&pp->pr_emptypages)) != NULL &&
+           (ticks - ph->ph_tick) > hz) {
+               freeph = ph;
                pool_p_remove(pp, freeph);
+       }
        mtx_leave(&pp->pr_mtx);
 
        if (freeph != NULL)