Date: Fri, 24 Aug 2012 09:58:15 +0000 (UTC) From: Dag-Erling Smørgrav <des@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r239645 - stable/9/sys/vm Message-ID: <201208240958.q7O9wF82010501@svn.freebsd.org>
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Author: des Date: Fri Aug 24 09:58:14 2012 New Revision: 239645 URL: http://svn.freebsd.org/changeset/base/239645 Log: MFH (r239327): warn when too much swap is configured, and avoid flooding the console when running out of space for metadata. Modified: stable/9/sys/vm/swap_pager.c Directory Properties: stable/9/sys/ (props changed) Modified: stable/9/sys/vm/swap_pager.c ============================================================================== --- stable/9/sys/vm/swap_pager.c Fri Aug 24 09:28:22 2012 (r239644) +++ stable/9/sys/vm/swap_pager.c Fri Aug 24 09:58:14 2012 (r239645) @@ -1804,6 +1804,7 @@ restart: static void swp_pager_meta_build(vm_object_t object, vm_pindex_t pindex, daddr_t swapblk) { + static volatile int exhausted; struct swblock *swap; struct swblock **pswap; int idx; @@ -1847,7 +1848,9 @@ retry: mtx_unlock(&swhash_mtx); VM_OBJECT_UNLOCK(object); if (uma_zone_exhausted(swap_zone)) { - printf("swap zone exhausted, increase kern.maxswzone\n"); + if (atomic_cmpset_rel_int(&exhausted, 0, 1)) + printf("swap zone exhausted, " + "increase kern.maxswzone\n"); vm_pageout_oom(VM_OOM_SWAPZ); pause("swzonex", 10); } else @@ -1856,6 +1859,9 @@ retry: goto retry; } + if (atomic_cmpset_rel_int(&exhausted, 1, 0)) + printf("swap zone ok\n"); + swap->swb_hnext = NULL; swap->swb_object = object; swap->swb_index = pindex & ~(vm_pindex_t)SWAP_META_MASK; @@ -2112,6 +2118,31 @@ done: return (error); } +/* + * Check that the total amount of swap currently configured does not + * exceed half the theoretical maximum. If it does, print a warning + * message and return -1; otherwise, return 0. + */ +static int +swapon_check_swzone(unsigned long npages) +{ + unsigned long maxpages; + + /* absolute maximum we can handle assuming 100% efficiency */ + maxpages = uma_zone_get_max(swap_zone) * SWAP_META_PAGES; + + /* recommend using no more than half that amount */ + if (npages > maxpages / 2) { + printf("warning: total configured swap (%lu pages) " + "exceeds maximum recommended amount (%lu pages).\n", + npages, maxpages); + printf("warning: increase kern.maxswzone " + "or reduce amount of swap.\n"); + return (-1); + } + return (0); +} + static void swaponsomething(struct vnode *vp, void *id, u_long nblks, sw_strategy_t *strategy, sw_close_t *close, dev_t dev) { @@ -2175,6 +2206,7 @@ swaponsomething(struct vnode *vp, void * nswapdev++; swap_pager_avail += nblks; swap_total += (vm_ooffset_t)nblks * PAGE_SIZE; + swapon_check_swzone(swap_total / PAGE_SIZE); swp_sizecheck(); mtx_unlock(&sw_dev_mtx); }
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