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diff --git a/storage/innobase/include/buf0buf.inl b/storage/innobase/include/buf0buf.inl
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+/*****************************************************************************
+
+Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2014, 2022, MariaDB Corporation.
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; version 2 of the License.
+
+This program is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
+
+*****************************************************************************/
+
+/**************************************************//**
+@file include/buf0buf.ic
+The database buffer buf_pool
+
+Created 11/5/1995 Heikki Tuuri
+*******************************************************/
+
+#include "buf0lru.h"
+
+/** Determine if a block is still close enough to the MRU end of the LRU list
+meaning that it is not in danger of getting evicted and also implying
+that it has been accessed recently.
+The page must be either buffer-fixed, or its page hash must be locked.
+@param[in]	bpage		buffer pool page
+@return whether bpage is close to MRU end of LRU */
+inline bool buf_page_peek_if_young(const buf_page_t *bpage)
+{
+	/* FIXME: bpage->freed_page_clock is 31 bits */
+	return((buf_pool.freed_page_clock & ((1UL << 31) - 1))
+	       < (bpage->freed_page_clock
+		  + (buf_pool.curr_size
+		     * (BUF_LRU_OLD_RATIO_DIV - buf_pool.LRU_old_ratio)
+		     / (BUF_LRU_OLD_RATIO_DIV * 4))));
+}
+
+/** Determine if a block should be moved to the start of the LRU list if
+there is danger of dropping from the buffer pool.
+@param[in]	bpage		buffer pool page
+@return true if bpage should be made younger */
+inline bool buf_page_peek_if_too_old(const buf_page_t *bpage)
+{
+	if (buf_pool.freed_page_clock == 0) {
+		/* If eviction has not started yet, do not update the
+		statistics or move blocks in the LRU list.  This is
+		either the warm-up phase or an in-memory workload. */
+		return(FALSE);
+	} else if (buf_LRU_old_threshold_ms && bpage->old) {
+		uint32_t access_time = bpage->is_accessed();
+
+		/* It is possible that the below comparison returns an
+		unexpected result. 2^32 milliseconds pass in about 50 days,
+		so if the difference between ut_time_ms() and access_time
+		is e.g. 50 days + 15 ms, then the below will behave as if
+		it is 15 ms. This is known and fixing it would require to
+		increase buf_page_t::access_time from 32 to 64 bits. */
+		if (access_time
+		    && ((ib_uint32_t) (ut_time_ms() - access_time))
+		    >= buf_LRU_old_threshold_ms) {
+			return(TRUE);
+		}
+
+		buf_pool.stat.n_pages_not_made_young++;
+		return false;
+	} else {
+		return !buf_page_peek_if_young(bpage);
+	}
+}
+
+/** Allocate a buffer block.
+@return own: the allocated block, in state BUF_BLOCK_MEMORY */
+inline buf_block_t *buf_block_alloc()
+{
+  return buf_LRU_get_free_block(false);
+}
+
+/********************************************************************//**
+Frees a buffer block which does not contain a file page. */
+UNIV_INLINE
+void
+buf_block_free(
+/*===========*/
+	buf_block_t*	block)	/*!< in, own: block to be freed */
+{
+	mysql_mutex_lock(&buf_pool.mutex);
+	buf_LRU_block_free_non_file_page(block);
+	mysql_mutex_unlock(&buf_pool.mutex);
+}
+
+/********************************************************************//**
+Increments the modify clock of a frame by 1. The caller must (1) own the
+buf_pool mutex and block bufferfix count has to be zero, (2) or own an x-lock
+on the block. */
+UNIV_INLINE
+void
+buf_block_modify_clock_inc(
+/*=======================*/
+	buf_block_t*	block)	/*!< in: block */
+{
+#ifdef SAFE_MUTEX
+	ut_ad((mysql_mutex_is_owner(&buf_pool.mutex)
+	       && !block->page.buf_fix_count())
+	      || block->page.lock.have_u_or_x());
+#else /* SAFE_MUTEX */
+	ut_ad(!block->page.buf_fix_count() || block->page.lock.have_u_or_x());
+#endif /* SAFE_MUTEX */
+	assert_block_ahi_valid(block);
+
+	block->modify_clock++;
+}
+
+/********************************************************************//**
+Returns the value of the modify clock. The caller must have an s-lock
+or x-lock on the block.
+@return value */
+UNIV_INLINE
+ib_uint64_t
+buf_block_get_modify_clock(
+/*=======================*/
+	buf_block_t*	block)	/*!< in: block */
+{
+	ut_ad(block->page.lock.have_any());
+	return(block->modify_clock);
+}