Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files. =================================================================== RCS file: /ftp/cvs/cvsroot/src/sys/kern/subr_pool.c,v retrieving revision 1.20 retrieving revision 1.21 diff -u -p -r1.20 -r1.21 --- src/sys/kern/subr_pool.c 1999/03/31 01:14:06 1.20 +++ src/sys/kern/subr_pool.c 1999/03/31 23:23:48 1.21 @@ -1,4 +1,4 @@ -/* $NetBSD: subr_pool.c,v 1.20 1999/03/31 01:14:06 thorpej Exp $ */ +/* $NetBSD: subr_pool.c,v 1.21 1999/03/31 23:23:48 thorpej Exp $ */ /*- * Copyright (c) 1997, 1999 The NetBSD Foundation, Inc. @@ -61,7 +61,6 @@ * headed by `ph_itemlist' in each page header. The memory for building * the page list is either taken from the allocated pages themselves (for * small pool items) or taken from an internal pool of page headers (`phpool'). - * */ /* List of all pools */ @@ -107,10 +106,13 @@ static struct pool_item_header *pr_find_pagehead __P((struct pool *, caddr_t)); static void pr_rmpage __P((struct pool *, struct pool_item_header *)); static int pool_catchup __P((struct pool *)); -static int pool_prime_page __P((struct pool *, caddr_t)); +static void pool_prime_page __P((struct pool *, caddr_t)); static void *pool_page_alloc __P((unsigned long, int, int)); static void pool_page_free __P((void *, unsigned long, int)); +#if defined(POOL_DIAGNOSTIC) || defined(DEBUG) +static void pool_print1 __P((struct pool *, const char *)); +#endif #ifdef POOL_DIAGNOSTIC /* @@ -173,7 +175,7 @@ pr_printlog(pp) if ((pp->pr_roflags & PR_LOGGING) == 0) return; - pool_print(pp, "printlog"); + pool_print1(pp, "printlog"); /* * Print all entries in this pool's log. @@ -252,11 +254,6 @@ pr_rmpage(pp, ph) pp->pr_npages--; pp->pr_npagefree++; - if ((pp->pr_roflags & PR_PHINPAGE) == 0) { - LIST_REMOVE(ph, ph_hashlist); - pool_put(&phpool, ph); - } - if (pp->pr_curpage == ph) { /* * Find a new non-empty page header, if any. @@ -270,6 +267,11 @@ pr_rmpage(pp, ph) pp->pr_curpage = ph; } + + if ((pp->pr_roflags & PR_PHINPAGE) == 0) { + LIST_REMOVE(ph, ph_hashlist); + pool_put(&phpool, ph); + } } /* @@ -281,7 +283,7 @@ pool_create(size, align, ioff, nitems, w u_int align; u_int ioff; int nitems; - char *wchan; + const char *wchan; size_t pagesz; void *(*alloc) __P((unsigned long, int, int)); void (*release) __P((void *, unsigned long, int)); @@ -326,7 +328,7 @@ pool_init(pp, size, align, ioff, flags, u_int align; u_int ioff; int flags; - char *wchan; + const char *wchan; size_t pagesz; void *(*alloc) __P((unsigned long, int, int)); void (*release) __P((void *, unsigned long, int)); @@ -445,8 +447,7 @@ pool_init(pp, size, align, ioff, flags, } #endif - simple_lock_init(&pp->pr_lock); - lockinit(&pp->pr_resourcelock, PSWP, wchan, 0, 0); + simple_lock_init(&pp->pr_slock); /* * Initialize private page header pool if we haven't done so yet. @@ -526,7 +527,7 @@ pool_get(pp, flags) if (curproc == NULL && (flags & PR_WAITOK) != 0) panic("pool_get: must have NOWAIT"); - simple_lock(&pp->pr_lock); + simple_lock(&pp->pr_slock); startover: /* @@ -536,7 +537,7 @@ pool_get(pp, flags) */ #ifdef DIAGNOSTIC if (pp->pr_nout > pp->pr_hardlimit) { - simple_unlock(&pp->pr_lock); + simple_unlock(&pp->pr_slock); panic("pool_get: %s: crossed hard limit", pp->pr_wchan); } #endif @@ -547,9 +548,9 @@ pool_get(pp, flags) * it be? */ pp->pr_flags |= PR_WANTED; - simple_unlock(&pp->pr_lock); + simple_unlock(&pp->pr_slock); tsleep((caddr_t)pp, PSWP, pp->pr_wchan, 0); - simple_lock(&pp->pr_lock); + simple_lock(&pp->pr_slock); goto startover; } if (pp->pr_hardlimit_warning != NULL) { @@ -567,7 +568,13 @@ pool_get(pp, flags) log(LOG_ERR, "%s\n", pp->pr_hardlimit_warning); } } - simple_unlock(&pp->pr_lock); + + if (flags & PR_URGENT) + panic("pool_get: urgent"); + + pp->pr_nfail++; + + simple_unlock(&pp->pr_slock); return (NULL); } @@ -579,39 +586,47 @@ pool_get(pp, flags) */ if ((ph = pp->pr_curpage) == NULL) { void *v; - int lkflags = LK_EXCLUSIVE | LK_INTERLOCK | - ((flags & PR_WAITOK) == 0 ? LK_NOWAIT : 0); #ifdef DIAGNOSTIC if (pp->pr_nitems != 0) { - simple_unlock(&pp->pr_lock); + simple_unlock(&pp->pr_slock); printf("pool_get: %s: curpage NULL, nitems %u\n", pp->pr_wchan, pp->pr_nitems); panic("pool_get: nitems inconsistent\n"); } #endif - /* Get long-term lock on pool */ - if (lockmgr(&pp->pr_resourcelock, lkflags, &pp->pr_lock) != 0) - return (NULL); - - /* Check if pool became non-empty while we slept */ - if ((ph = pp->pr_curpage) != NULL) - goto again; - - /* Call the page back-end allocator for more memory */ + /* + * Call the back-end page allocator for more memory. + * Release the pool lock, as the back-end page allocator + * may block. + */ + simple_unlock(&pp->pr_slock); v = (*pp->pr_alloc)(pp->pr_pagesz, flags, pp->pr_mtype); + simple_lock(&pp->pr_slock); + if (v == NULL) { + /* + * We were unable to allocate a page, but + * we released the lock during allocation, + * so perhaps items were freed back to the + * pool. Check for this case. + */ + if (pp->pr_curpage != NULL) + goto startover; + if (flags & PR_URGENT) panic("pool_get: urgent"); + if ((flags & PR_WAITOK) == 0) { pp->pr_nfail++; - lockmgr(&pp->pr_resourcelock, LK_RELEASE, NULL); + simple_unlock(&pp->pr_slock); return (NULL); } /* * Wait for items to be returned to this pool. + * * XXX: we actually want to wait just until * the page allocator has memory again. Depending * on this pool's usage, we might get stuck here @@ -620,12 +635,10 @@ pool_get(pp, flags) * XXX: maybe we should wake up once a second and * try again? */ - simple_lock(&pp->pr_lock); - (void) lockmgr(&pp->pr_resourcelock, LK_RELEASE, NULL); pp->pr_flags |= PR_WANTED; - simple_unlock(&pp->pr_lock); + simple_unlock(&pp->pr_slock); tsleep((caddr_t)pp, PSWP, pp->pr_wchan, 0); - simple_lock(&pp->pr_lock); + simple_lock(&pp->pr_slock); goto startover; } @@ -633,20 +646,17 @@ pool_get(pp, flags) pp->pr_npagealloc++; pool_prime_page(pp, v); - again: - /* Re-acquire pool interlock */ - simple_lock(&pp->pr_lock); - lockmgr(&pp->pr_resourcelock, LK_RELEASE, NULL); - /* Start the allocation process over. */ goto startover; } - if ((v = pi = TAILQ_FIRST(&ph->ph_itemlist)) == NULL) + if ((v = pi = TAILQ_FIRST(&ph->ph_itemlist)) == NULL) { + simple_unlock(&pp->pr_slock); panic("pool_get: %s: page empty", pp->pr_wchan); + } #ifdef DIAGNOSTIC if (pp->pr_nitems == 0) { - simple_unlock(&pp->pr_lock); + simple_unlock(&pp->pr_slock); printf("pool_get: %s: items on itemlist, nitems %u\n", pp->pr_wchan, pp->pr_nitems); panic("pool_get: nitems inconsistent\n"); @@ -678,17 +688,28 @@ pool_get(pp, flags) } ph->ph_nmissing++; if (TAILQ_FIRST(&ph->ph_itemlist) == NULL) { +#ifdef DIAGNOSTIC + if (ph->ph_nmissing != pp->pr_itemsperpage) { + simple_unlock(&pp->pr_slock); + panic("pool_get: %s: nmissing inconsistent", + pp->pr_wchan); + } +#endif /* * Find a new non-empty page header, if any. * Start search from the page head, to increase * the chance for "high water" pages to be freed. * - * First, move the now empty page to the head of - * the page list. + * Migrate empty pages to the end of the list. This + * will speed the update of curpage as pages become + * idle. Empty pages intermingled with idle pages + * is no big deal. As soon as a page becomes un-empty, + * it will move back to the head of the list. */ TAILQ_REMOVE(&pp->pr_pagelist, ph, ph_pagelist); - TAILQ_INSERT_HEAD(&pp->pr_pagelist, ph, ph_pagelist); - while ((ph = TAILQ_NEXT(ph, ph_pagelist)) != NULL) + TAILQ_INSERT_TAIL(&pp->pr_pagelist, ph, ph_pagelist); + for (ph = TAILQ_FIRST(&pp->pr_pagelist); ph != NULL; + ph = TAILQ_NEXT(ph, ph_pagelist)) if (TAILQ_FIRST(&ph->ph_itemlist) != NULL) break; @@ -709,7 +730,7 @@ pool_get(pp, flags) */ } - simple_unlock(&pp->pr_lock); + simple_unlock(&pp->pr_slock); return (v); } @@ -733,10 +754,11 @@ pool_put(pp, v) struct pool_item *pi = v; struct pool_item_header *ph; caddr_t page; + int s; page = (caddr_t)((u_long)v & pp->pr_pagemask); - simple_lock(&pp->pr_lock); + simple_lock(&pp->pr_slock); pr_log(pp, v, PRLOG_PUT, file, line); @@ -765,29 +787,51 @@ pool_put(pp, v) pp->pr_flags &= ~PR_WANTED; if (ph->ph_nmissing == 0) pp->pr_nidle++; + simple_unlock(&pp->pr_slock); wakeup((caddr_t)pp); - simple_unlock(&pp->pr_lock); return; } /* - * If this page is now complete, move it to the end of the pagelist. - * If this page has just become un-empty, move it the head. + * If this page is now complete, do one of two things: + * + * (1) If we have more pages than the page high water + * mark, free the page back to the system. + * + * (2) Move it to the end of the page list, so that + * we minimize our chances of fragmenting the + * pool. Idle pages migrate to the end (along with + * completely empty pages, so that we find un-empty + * pages more quickly when we update curpage) of the + * list so they can be more easily swept up by + * the pagedaemon when pages are scarce. */ if (ph->ph_nmissing == 0) { pp->pr_nidle++; if (pp->pr_npages > pp->pr_maxpages) { -#if 0 - timeout(pool_drain, 0, pool_inactive_time*hz); -#else pr_rmpage(pp, ph); -#endif } else { TAILQ_REMOVE(&pp->pr_pagelist, ph, ph_pagelist); TAILQ_INSERT_TAIL(&pp->pr_pagelist, ph, ph_pagelist); - ph->ph_time = time; - /* XXX - update curpage */ + /* + * Update the timestamp on the page. A page must + * be idle for some period of time before it can + * be reclaimed by the pagedaemon. This minimizes + * ping-pong'ing for memory. + */ + s = splclock(); + ph->ph_time = mono_time; + splx(s); + + /* + * Update the current page pointer. Just look for + * the first page with any free items. + * + * XXX: Maybe we want an option to look for the + * page with the fewest available items, to minimize + * fragmentation? + */ for (ph = TAILQ_FIRST(&pp->pr_pagelist); ph != NULL; ph = TAILQ_NEXT(ph, ph_pagelist)) if (TAILQ_FIRST(&ph->ph_itemlist) != NULL) @@ -796,8 +840,20 @@ pool_put(pp, v) pp->pr_curpage = ph; } } + /* + * If the page has just become un-empty, move it to the head of + * the list, and make it the current page. The next allocation + * will get the item from this page, instead of further fragmenting + * the pool. + */ + else if (ph->ph_nmissing == (pp->pr_itemsperpage - 1)) { + TAILQ_REMOVE(&pp->pr_pagelist, ph, ph_pagelist); + TAILQ_INSERT_HEAD(&pp->pr_pagelist, ph, ph_pagelist); + pp->pr_curpage = ph; + } + + simple_unlock(&pp->pr_slock); - simple_unlock(&pp->pr_lock); } /* @@ -818,23 +874,25 @@ pool_prime(pp, n, storage) /* !storage && static caught below */ #endif - (void)lockmgr(&pp->pr_resourcelock, LK_EXCLUSIVE, NULL); + simple_lock(&pp->pr_slock); + newnitems = pp->pr_minitems + n; newpages = roundup(newnitems, pp->pr_itemsperpage) / pp->pr_itemsperpage - pp->pr_minpages; while (newpages-- > 0) { - if (pp->pr_roflags & PR_STATIC) { cp = storage; storage += pp->pr_pagesz; } else { + simple_unlock(&pp->pr_slock); cp = (*pp->pr_alloc)(pp->pr_pagesz, 0, pp->pr_mtype); + simple_lock(&pp->pr_slock); } if (cp == NULL) { - (void)lockmgr(&pp->pr_resourcelock, LK_RELEASE, NULL); + simple_unlock(&pp->pr_slock); return (ENOMEM); } @@ -847,14 +905,16 @@ pool_prime(pp, n, storage) if (pp->pr_minpages >= pp->pr_maxpages) pp->pr_maxpages = pp->pr_minpages + 1; /* XXX */ - (void)lockmgr(&pp->pr_resourcelock, LK_RELEASE, NULL); + simple_unlock(&pp->pr_slock); return (0); } /* * Add a page worth of items to the pool. + * + * Note, we must be called with the pool descriptor LOCKED. */ -static int +static void pool_prime_page(pp, storage) struct pool *pp; caddr_t storage; @@ -866,8 +926,6 @@ pool_prime_page(pp, storage) unsigned int ioff = pp->pr_itemoffset; int n; - simple_lock(&pp->pr_lock); - if ((pp->pr_roflags & PR_PHINPAGE) != 0) { ph = (struct pool_item_header *)(cp + pp->pr_phoffset); } else { @@ -883,7 +941,7 @@ pool_prime_page(pp, storage) TAILQ_INIT(&ph->ph_itemlist); ph->ph_page = storage; ph->ph_nmissing = 0; - ph->ph_time.tv_sec = ph->ph_time.tv_usec = 0; + memset(&ph->ph_time, 0, sizeof(ph->ph_time)); pp->pr_nidle++; @@ -925,9 +983,6 @@ pool_prime_page(pp, storage) if (++pp->pr_npages > pp->pr_hiwat) pp->pr_hiwat = pp->pr_npages; - - simple_unlock(&pp->pr_lock); - return (0); } /* @@ -935,8 +990,7 @@ pool_prime_page(pp, storage) * drops below the low water mark. This is used to catch up nitmes * with the low water mark. * - * Note 1, we never wait for memory or locks here, we let the caller - * decide what to do. + * Note 1, we never wait for memory here, we let the caller decide what to do. * * Note 2, this doesn't work with static pools. * @@ -949,53 +1003,34 @@ pool_catchup(pp) { caddr_t cp; int error = 0; - u_long nitems; if (pp->pr_roflags & PR_STATIC) { /* * We dropped below the low water mark, and this is not a * good thing. Log a warning. + * + * XXX: rate-limit this? */ printf("WARNING: static pool `%s' dropped below low water " "mark\n", pp->pr_wchan); return (0); } - for (;;) { + while (pp->pr_nitems < pp->pr_minitems) { /* - * Pool is locked; get the current number of items - * availabler. + * Call the page back-end allocator for more memory. + * + * XXX: We never wait, so should we bother unlocking + * the pool descriptor? */ - nitems = pp->pr_nitems; - - /* Acquire the resource lock and release the interlock. */ - error = lockmgr(&pp->pr_resourcelock, - LK_EXCLUSIVE | LK_INTERLOCK | LK_NOWAIT, &pp->pr_lock); - if (error) - break; - - if (nitems >= pp->pr_minitems) { - simple_lock(&pp->pr_lock); - (void) lockmgr(&pp->pr_resourcelock, LK_RELEASE, - NULL); - break; - } - - /* Call the page back-end allocator for more memory. */ + simple_unlock(&pp->pr_slock); cp = (*pp->pr_alloc)(pp->pr_pagesz, 0, pp->pr_mtype); + simple_lock(&pp->pr_slock); if (cp == NULL) { - simple_lock(&pp->pr_lock); - (void) lockmgr(&pp->pr_resourcelock, LK_RELEASE, - NULL); error = ENOMEM; break; } - pool_prime_page(pp, cp); - - simple_lock(&pp->pr_lock); - (void) lockmgr(&pp->pr_resourcelock, LK_RELEASE, - NULL); } return (error); @@ -1008,25 +1043,23 @@ pool_setlowat(pp, n) { int error; - (void)lockmgr(&pp->pr_resourcelock, LK_EXCLUSIVE, NULL); + simple_lock(&pp->pr_slock); + pp->pr_minitems = n; pp->pr_minpages = (n == 0) ? 0 : roundup(n, pp->pr_itemsperpage) / pp->pr_itemsperpage; - (void)lockmgr(&pp->pr_resourcelock, LK_RELEASE, NULL); /* Make sure we're caught up with the newly-set low water mark. */ - simple_lock(&pp->pr_lock); - error = pool_catchup(pp); - simple_unlock(&pp->pr_lock); - - if (error) { + if ((error = pool_catchup(pp)) != 0) { /* * XXX: Should we log a warning? Should we set up a timeout * to try again in a second or so? The latter could break * a caller's assumptions about interrupt protection, etc. */ } + + simple_unlock(&pp->pr_slock); } void @@ -1035,11 +1068,13 @@ pool_sethiwat(pp, n) int n; { - (void)lockmgr(&pp->pr_resourcelock, LK_EXCLUSIVE, NULL); + simple_lock(&pp->pr_slock); + pp->pr_maxpages = (n == 0) ? 0 : roundup(n, pp->pr_itemsperpage) / pp->pr_itemsperpage; - (void)lockmgr(&pp->pr_resourcelock, LK_RELEASE, NULL); + + simple_unlock(&pp->pr_slock); } void @@ -1050,7 +1085,7 @@ pool_sethardlimit(pp, n, warnmess, ratec int ratecap; { - simple_lock(&pp->pr_lock); + simple_lock(&pp->pr_slock); pp->pr_hardlimit = n; pp->pr_hardlimit_warning = warnmess; @@ -1059,15 +1094,14 @@ pool_sethardlimit(pp, n, warnmess, ratec sizeof(pp->pr_hardlimit_warning_last)); /* - * In-line version of pool_sethiwat(), because we need to release - * the interlock. + * In-line version of pool_sethiwat(), because we don't want to + * release the lock. */ - (void)lockmgr(&pp->pr_resourcelock, LK_EXCLUSIVE | LK_INTERLOCK, - &pp->pr_lock); pp->pr_maxpages = (n == 0) ? 0 : roundup(n, pp->pr_itemsperpage) / pp->pr_itemsperpage; - (void)lockmgr(&pp->pr_resourcelock, LK_RELEASE, NULL); + + simple_unlock(&pp->pr_slock); } /* @@ -1106,9 +1140,6 @@ pool_page_alloc_nointr(sz, flags, mtype) { boolean_t waitok = (flags & PR_WAITOK) ? TRUE : FALSE; - /* - * With UVM, we can use the kernel_map. - */ return ((void *)uvm_km_alloc_poolpage1(kernel_map, uvm.kernel_object, waitok)); } @@ -1128,18 +1159,23 @@ pool_page_free_nointr(v, sz, mtype) * Release all complete pages that have not been used recently. */ void -pool_reclaim (pp) +pool_reclaim(pp) pool_handle_t pp; { struct pool_item_header *ph, *phnext; - struct timeval curtime = time; + struct timeval curtime; + int s; if (pp->pr_roflags & PR_STATIC) return; - if (simple_lock_try(&pp->pr_lock) == 0) + if (simple_lock_try(&pp->pr_slock) == 0) return; + s = splclock(); + curtime = mono_time; + splx(s); + for (ph = TAILQ_FIRST(&pp->pr_pagelist); ph != NULL; ph = phnext) { phnext = TAILQ_NEXT(ph, ph_pagelist); @@ -1152,16 +1188,27 @@ pool_reclaim (pp) timersub(&curtime, &ph->ph_time, &diff); if (diff.tv_sec < pool_inactive_time) continue; + + /* + * If freeing this page would put us below + * the low water mark, stop now. + */ + if ((pp->pr_nitems - pp->pr_itemsperpage) < + pp->pr_minitems) + break; + pr_rmpage(pp, ph); } } - simple_unlock(&pp->pr_lock); + simple_unlock(&pp->pr_slock); } /* * Drain pools, one at a time. + * + * Note, we must never be called from an interrupt context. */ void pool_drain(arg) @@ -1192,7 +1239,21 @@ pool_drain(arg) void pool_print(pp, label) struct pool *pp; - char *label; + const char *label; +{ + int s; + + s = splimp(); + simple_lock(&pp->pr_slock); + pool_print1(pp, label); + simple_unlock(&pp->pr_slock); + splx(s); +} + +static void +pool_print1(pp, label) + struct pool *pp; + const char *label; { if (label != NULL) @@ -1221,7 +1282,7 @@ pool_chk(pp, label) struct pool_item_header *ph; int r = 0; - simple_lock(&pp->pr_lock); + simple_lock(&pp->pr_slock); for (ph = TAILQ_FIRST(&pp->pr_pagelist); ph != NULL; ph = TAILQ_NEXT(ph, ph_pagelist)) { @@ -1274,7 +1335,7 @@ pool_chk(pp, label) } } out: - simple_unlock(&pp->pr_lock); + simple_unlock(&pp->pr_slock); return (r); } #endif /* POOL_DIAGNOSTIC || DEBUG */