diff options
Diffstat (limited to 'src/include/btree.i')
| -rw-r--r-- | src/include/btree.i | 37 |
1 files changed, 33 insertions, 4 deletions
diff --git a/src/include/btree.i b/src/include/btree.i index b6c425bed0e..f64e80e7d12 100644 --- a/src/include/btree.i +++ b/src/include/btree.i @@ -44,6 +44,34 @@ __wt_cache_page_inmem_incr(WT_SESSION_IMPL *session, WT_PAGE *page, size_t size) } } +/* + * WT_CACHE_DECR -- + * Macro to decrement a field by a size. + * + * Be defensive and don't underflow: a band-aid on a gaping wound, but underflow + * won't make things better no matter the problem (specifically, underflow makes + * eviction crazy trying to evict non-existent memory). + */ +#ifdef HAVE_DIAGNOSTIC +#define WT_CACHE_DECR(session, f, sz) do { \ + static int __first = 1; \ + if (WT_ATOMIC_SUB8(f, sz) > WT_EXABYTE) { \ + (void)WT_ATOMIC_ADD8(f, sz); \ + if (__first) { \ + __wt_errx(session, \ + "%s underflow: decrementing %" WT_SIZET_FMT,\ + #f, sz); \ + __first = 0; \ + } \ + } \ +} while (0) +#else +#define WT_CACHE_DECR(s, f, sz) do { \ + if (WT_ATOMIC_SUB8(f, sz) > WT_EXABYTE) \ + (void)WT_ATOMIC_ADD8(f, sz); \ +} while (0) +#endif + /* * __wt_cache_page_inmem_decr -- * Decrement a page's memory footprint in the cache. @@ -54,11 +82,12 @@ __wt_cache_page_inmem_decr(WT_SESSION_IMPL *session, WT_PAGE *page, size_t size) WT_CACHE *cache; cache = S2C(session)->cache; - (void)WT_ATOMIC_SUB8(cache->bytes_inmem, size); - (void)WT_ATOMIC_SUB8(page->memory_footprint, size); + + WT_CACHE_DECR(session, cache->bytes_inmem, size); + WT_CACHE_DECR(session, page->memory_footprint, size); if (__wt_page_is_modified(page)) { - (void)WT_ATOMIC_SUB8(cache->bytes_dirty, size); - (void)WT_ATOMIC_SUB8(page->modify->bytes_dirty, size); + WT_CACHE_DECR(session, cache->bytes_dirty, size); + WT_CACHE_DECR(session, page->modify->bytes_dirty, size); } } |