// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  Swap reorganised 29.12.95, Stephen Tweedie.
 *  kswapd added: 7.1.96  sct
 *  Removed kswapd_ctl limits, and swap out as many pages as needed
 *  to bring the system back to freepages.high: 2.4.97, Rik van Riel.
 *  Zone aware kswapd started 02/00, Kanoj Sarcar (kanoj@sgi.com).
 *  Multiqueue VM started 5.8.00, Rik van Riel.
 */

/* Extracted unchanged from Linux v6.12, mm/vmscan.c:74-184.
 * Full struct declaration; surrounding kernel context is required.
 * Source: https://github.com/torvalds/linux/blob/v6.12/mm/vmscan.c#L74
 * License text: GPL-2.0.txt (in this directory).
 */
struct scan_control {
	/* How many pages shrink_list() should reclaim */
	unsigned long nr_to_reclaim;

	/*
	 * Nodemask of nodes allowed by the caller. If NULL, all nodes
	 * are scanned.
	 */
	nodemask_t	*nodemask;

	/*
	 * The memory cgroup that hit its limit and as a result is the
	 * primary target of this reclaim invocation.
	 */
	struct mem_cgroup *target_mem_cgroup;

	/*
	 * Scan pressure balancing between anon and file LRUs
	 */
	unsigned long	anon_cost;
	unsigned long	file_cost;

#ifdef CONFIG_MEMCG
	/* Swappiness value for proactive reclaim. Always use sc_swappiness()! */
	int *proactive_swappiness;
#endif

	/* Can active folios be deactivated as part of reclaim? */
#define DEACTIVATE_ANON 1
#define DEACTIVATE_FILE 2
	unsigned int may_deactivate:2;
	unsigned int force_deactivate:1;
	unsigned int skipped_deactivate:1;

	/* Writepage batching in laptop mode; RECLAIM_WRITE */
	unsigned int may_writepage:1;

	/* Can mapped folios be reclaimed? */
	unsigned int may_unmap:1;

	/* Can folios be swapped as part of reclaim? */
	unsigned int may_swap:1;

	/* Not allow cache_trim_mode to be turned on as part of reclaim? */
	unsigned int no_cache_trim_mode:1;

	/* Has cache_trim_mode failed at least once? */
	unsigned int cache_trim_mode_failed:1;

	/* Proactive reclaim invoked by userspace through memory.reclaim */
	unsigned int proactive:1;

	/*
	 * Cgroup memory below memory.low is protected as long as we
	 * don't threaten to OOM. If any cgroup is reclaimed at
	 * reduced force or passed over entirely due to its memory.low
	 * setting (memcg_low_skipped), and nothing is reclaimed as a
	 * result, then go back for one more cycle that reclaims the protected
	 * memory (memcg_low_reclaim) to avert OOM.
	 */
	unsigned int memcg_low_reclaim:1;
	unsigned int memcg_low_skipped:1;

	/* Shared cgroup tree walk failed, rescan the whole tree */
	unsigned int memcg_full_walk:1;

	unsigned int hibernation_mode:1;

	/* One of the zones is ready for compaction */
	unsigned int compaction_ready:1;

	/* There is easily reclaimable cold cache in the current node */
	unsigned int cache_trim_mode:1;

	/* The file folios on the current node are dangerously low */
	unsigned int file_is_tiny:1;

	/* Always discard instead of demoting to lower tier memory */
	unsigned int no_demotion:1;

	/* Allocation order */
	s8 order;

	/* Scan (total_size >> priority) pages at once */
	s8 priority;

	/* The highest zone to isolate folios for reclaim from */
	s8 reclaim_idx;

	/* This context's GFP mask */
	gfp_t gfp_mask;

	/* Incremented by the number of inactive pages that were scanned */
	unsigned long nr_scanned;

	/* Number of pages freed so far during a call to shrink_zones() */
	unsigned long nr_reclaimed;

	struct {
		unsigned int dirty;
		unsigned int unqueued_dirty;
		unsigned int congested;
		unsigned int writeback;
		unsigned int immediate;
		unsigned int file_taken;
		unsigned int taken;
	} nr;

	/* for recording the reclaimed slab by now */
	struct reclaim_state reclaim_state;
};