/*
* __hazard_exclusive --
* Request exclusive access to a page.
*/
static int
__hazard_exclusive(WT_SESSION_IMPL *session, WT_REF *ref, int top)
{
/*
* Make sure there is space to track exclusive access so we can unlock
* to clean up.
*/
WT_RET(__wt_realloc_def(session, &session->excl_allocated,
session->excl_next + 1, &session->excl));
/*
* Hazard pointers are acquired down the tree, which means we can't
* deadlock.
*
* Request exclusive access to the page. The top-level page should
* already be in the locked state, lock child pages in memory.
* If another thread already has this page, give up.
*/
if (!top && !WT_ATOMIC_CAS(ref->state, WT_REF_MEM, WT_REF_LOCKED))
return (EBUSY); /* We couldn't change the state. */
WT_ASSERT(session, ref->state == WT_REF_LOCKED);
session->excl[session->excl_next++] = ref;
/* Check for a matching hazard pointer. */
if (__wt_page_hazard_check(session, ref->page) == NULL)
return (0);
WT_STAT_FAST_DATA_INCR(session, cache_eviction_hazard);
WT_STAT_FAST_CONN_INCR(session, cache_eviction_hazard);
WT_VERBOSE_RET(
session, evict, "page %p hazard request failed", ref->page);
return (EBUSY);
}
/*
* __wt_page_out --
* Discard an in-memory page, freeing all memory associated with it.
*/
void
__wt_page_out(WT_SESSION_IMPL *session, WT_PAGE **pagep)
{
WT_PAGE *page;
/*
* When a page is discarded, it's been disconnected from its parent and
* its parent's WT_REF structure may now point to a different page.
* Make sure we don't accidentally use the page itself or any other
* information.
*/
page = *pagep;
*pagep = NULL;
page->parent = NULL;
page->ref = NULL;
WT_ASSERT(session, !F_ISSET_ATOMIC(page, WT_PAGE_EVICT_LRU));
#ifdef HAVE_DIAGNOSTIC
{
WT_HAZARD *hp;
if ((hp = __wt_page_hazard_check(session, page)) != NULL)
__wt_errx(session,
"discarded page has hazard pointer: (%p: %s, line %d)",
hp->page, hp->file, hp->line);
}
#endif
/* Update the cache's information. */
__wt_cache_page_evict(session, page);
/* Free the page modification information. */
if (page->modify != NULL)
__free_page_modify(session, page);
switch (page->type) {
case WT_PAGE_COL_FIX:
break;
case WT_PAGE_COL_INT:
__free_page_col_int(session, page);
break;
case WT_PAGE_COL_VAR:
__free_page_col_var(session, page);
break;
case WT_PAGE_ROW_INT:
__free_page_row_int(session, page);
break;
case WT_PAGE_ROW_LEAF:
__free_page_row_leaf(session, page);
break;
}
/* Free any allocated disk image. */
if (!F_ISSET_ATOMIC(page, WT_PAGE_DISK_NOT_ALLOC))
__wt_free(session, page->dsk);
__wt_overwrite_and_free(session, page);
}
/*
* __wt_page_out --
* Discard an in-memory page, freeing all memory associated with it.
*/
void
__wt_page_out(WT_SESSION_IMPL *session, WT_PAGE **pagep)
{
WT_PAGE *page;
WT_PAGE_HEADER *dsk;
WT_PAGE_MODIFY *mod;
/*
* Kill our caller's reference, do our best to catch races.
*/
page = *pagep;
*pagep = NULL;
if (F_ISSET(session->dhandle, WT_DHANDLE_DEAD))
__wt_page_modify_clear(session, page);
/*
* We should never discard:
* - a dirty page,
* - a page queued for eviction, or
* - a locked page.
*/
WT_ASSERT(session, !__wt_page_is_modified(page));
WT_ASSERT(session, !F_ISSET_ATOMIC(page, WT_PAGE_EVICT_LRU));
WT_ASSERT(session, !__wt_fair_islocked(session, &page->page_lock));
#ifdef HAVE_DIAGNOSTIC
{
WT_HAZARD *hp;
int i;
/*
* Make sure no other thread has a hazard pointer on the page we are
* about to discard. This is complicated by the fact that readers
* publish their hazard pointer before re-checking the page state, so
* our check can race with readers without indicating a real problem.
* Wait for up to a second for hazard pointers to be cleared.
*/
for (hp = NULL, i = 0; i < 100; i++) {
if ((hp = __wt_page_hazard_check(session, page)) == NULL)
break;
__wt_sleep(0, 10000);
}
if (hp != NULL)
__wt_errx(session,
"discarded page has hazard pointer: (%p: %s, line %d)",
hp->page, hp->file, hp->line);
WT_ASSERT(session, hp == NULL);
}
#endif
/*
* If a root page split, there may be one or more pages linked from the
* page; walk the list, discarding pages.
*/
switch (page->type) {
case WT_PAGE_COL_INT:
case WT_PAGE_ROW_INT:
mod = page->modify;
if (mod != NULL && mod->mod_root_split != NULL)
__wt_page_out(session, &mod->mod_root_split);
break;
}
/* Update the cache's information. */
__wt_cache_page_evict(session, page);
/*
* If discarding the page as part of process exit, the application may
* configure to leak the memory rather than do the work.
*/
if (F_ISSET(S2C(session), WT_CONN_LEAK_MEMORY))
return;
/* Free the page modification information. */
if (page->modify != NULL)
__free_page_modify(session, page);
switch (page->type) {
case WT_PAGE_COL_FIX:
break;
case WT_PAGE_COL_INT:
case WT_PAGE_ROW_INT:
__free_page_int(session, page);
break;
case WT_PAGE_COL_VAR:
__free_page_col_var(session, page);
break;
case WT_PAGE_ROW_LEAF:
__free_page_row_leaf(session, page);
break;
}
/* Discard any disk image. */
dsk = (WT_PAGE_HEADER *)page->dsk;
if (F_ISSET_ATOMIC(page, WT_PAGE_DISK_ALLOC))
__wt_overwrite_and_free_len(session, dsk, dsk->mem_size);
if (F_ISSET_ATOMIC(page, WT_PAGE_DISK_MAPPED))
(void)__wt_mmap_discard(session, dsk, dsk->mem_size);
__wt_overwrite_and_free(session, page);
}
