/*
* __wt_block_discard --
* Discard blocks from the system buffer cache.
*/
int
__wt_block_discard(WT_SESSION_IMPL *session, WT_BLOCK *block, size_t added_size)
{
WT_DECL_RET;
WT_FILE_HANDLE *handle;
/* The file may not support this call. */
handle = block->fh->handle;
if (handle->fh_advise == NULL)
return (0);
/* The call may not be configured. */
if (block->os_cache_max == 0)
return (0);
/*
* We're racing on the addition, but I'm not willing to serialize on it
* in the standard read path without evidence it's needed.
*/
if ((block->os_cache += added_size) <= block->os_cache_max)
return (0);
block->os_cache = 0;
ret = handle->fh_advise(handle, (WT_SESSION *)session,
(wt_off_t)0, (wt_off_t)0, WT_FILE_HANDLE_DONTNEED);
return (ret == EBUSY || ret == ENOTSUP ? 0 : ret);
}
/*
* __wt_bm_preload --
* Pre-load a page.
*/
int
__wt_bm_preload(
WT_BM *bm, WT_SESSION_IMPL *session, const uint8_t *addr, size_t addr_size)
{
WT_BLOCK *block;
WT_DECL_ITEM(tmp);
WT_DECL_RET;
WT_FILE_HANDLE *handle;
wt_off_t offset;
uint32_t cksum, size;
bool mapped;
WT_UNUSED(addr_size);
block = bm->block;
WT_STAT_FAST_CONN_INCR(session, block_preload);
/* Crack the cookie. */
WT_RET(__wt_block_buffer_to_addr(block, addr, &offset, &size, &cksum));
handle = block->fh->handle;
mapped = bm->map != NULL && offset + size <= (wt_off_t)bm->maplen;
if (mapped && handle->fh_map_preload != NULL)
ret = handle->fh_map_preload(handle, (WT_SESSION *)session,
(uint8_t *)bm->map + offset, size, bm->mapped_cookie);
if (!mapped && handle->fh_advise != NULL)
ret = handle->fh_advise(handle, (WT_SESSION *)session,
(wt_off_t)offset, (wt_off_t)size, WT_FILE_HANDLE_WILLNEED);
if (ret != EBUSY && ret != ENOTSUP)
return (ret);
/* If preload isn't supported, do it the slow way. */
WT_RET(__wt_scr_alloc(session, 0, &tmp));
ret = __wt_bm_read(bm, session, tmp, addr, addr_size);
__wt_scr_free(session, &tmp);
return (ret);
}
