Commit e5ca8071 authored by Yafang Shao's avatar Yafang Shao Committed by Linus Torvalds
Browse files

mm/vmscan.c: add a new member reclaim_state in struct shrink_control 

Patch series "mm/vmscan: calculate reclaimed slab in all reclaim paths".

This patchset is to fix the issues in doing shrink slab.

There're six different reclaim paths by now,
 - kswapd reclaim path
 - node reclaim path
 - hibernate preallocate memory reclaim path
 - direct reclaim path
 - memcg reclaim path
 - memcg softlimit reclaim path

The slab caches reclaimed in these paths are only calculated in the
above three paths.  The issues are detailed explained in patch #2.  We
should calculate the reclaimed slab caches in every reclaim path.  In
order to do it, the struct reclaim_state is placed into the struct
shrink_control.

In node reclaim path, there'is another issue about shrinking slab, which
is adressed in "mm/vmscan: shrink slab in node reclaim"
(https://lore.kernel.org/linux-mm/1559874946-22960-1-git-send-email-laoar.shao@gmail.com/).

This patch (of 2):

The struct reclaim_state is used to record how many slab caches are
reclaimed in one reclaim path.  The struct shrink_control is used to
control one reclaim path.  So we'd better put reclaim_state into
shrink_control.

[laoar.shao@gmail.com: remove reclaim_state assignment from __perform_reclaim()]
Link: http://lkml.kernel.org/r/1561381582-13697-1-git-send-email-laoar.shao@gmail.com
Link: http://lkml.kernel.org/r/1561112086-6169-2-git-send-email-laoar.shao@gmail.com


Signed-off-by: default avatarYafang Shao <laoar.shao@gmail.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarKirill Tkhai <ktkhai@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 766a4c19

mm/page_alloc.c

+0 −4
Original line number Diff line number Diff line
@@ -4102,7 +4102,6 @@ static int 
__perform_reclaim(gfp_t gfp_mask, unsigned int order,

					const struct alloc_context *ac)

{

	struct reclaim_state reclaim_state;

	int progress;

	unsigned int noreclaim_flag;

	unsigned long pflags;
@@ -4114,13 +4113,10 @@ __perform_reclaim(gfp_t gfp_mask, unsigned int order, 
	psi_memstall_enter(&pflags);

	fs_reclaim_acquire(gfp_mask);

	noreclaim_flag = memalloc_noreclaim_save();

	reclaim_state.reclaimed_slab = 0;

	current->reclaim_state = &reclaim_state;



	progress = try_to_free_pages(ac->zonelist, order, gfp_mask,

								ac->nodemask);



	current->reclaim_state = NULL;

	memalloc_noreclaim_restore(noreclaim_flag);

	fs_reclaim_release(gfp_mask);

	psi_memstall_leave(&pflags);

mm/vmscan.c

+8 −12
Original line number Diff line number Diff line
@@ -131,6 +131,9 @@ struct scan_control { 
		unsigned int file_taken;

		unsigned int taken;

	} nr;



	/* for recording the reclaimed slab by now */

	struct reclaim_state reclaim_state;

};



#ifdef ARCH_HAS_PREFETCH
@@ -3483,6 +3486,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx) 
		.may_unmap = 1,

	};



	current->reclaim_state = &sc.reclaim_state;

	psi_memstall_enter(&pflags);

	__fs_reclaim_acquire();
@@ -3664,6 +3668,8 @@ out: 
	snapshot_refaults(NULL, pgdat);

	__fs_reclaim_release();

	psi_memstall_leave(&pflags);

	current->reclaim_state = NULL;



	/*

	 * Return the order kswapd stopped reclaiming at as

	 * prepare_kswapd_sleep() takes it into account. If another caller
@@ -3787,15 +3793,10 @@ static int kswapd(void *p) 
	unsigned int classzone_idx = MAX_NR_ZONES - 1;

	pg_data_t *pgdat = (pg_data_t*)p;

	struct task_struct *tsk = current;



	struct reclaim_state reclaim_state = {

		.reclaimed_slab = 0,

	};

	const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);



	if (!cpumask_empty(cpumask))

		set_cpus_allowed_ptr(tsk, cpumask);

	current->reclaim_state = &reclaim_state;



	/*

	 * Tell the memory management that we're a "memory allocator",
@@ -3857,7 +3858,6 @@ kswapd_try_sleep: 
	}



	tsk->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD);

	current->reclaim_state = NULL;



	return 0;

}
@@ -3922,7 +3922,6 @@ void wakeup_kswapd(struct zone *zone, gfp_t gfp_flags, int order, 
 */

unsigned long shrink_all_memory(unsigned long nr_to_reclaim)

{

	struct reclaim_state reclaim_state;

	struct scan_control sc = {

		.nr_to_reclaim = nr_to_reclaim,

		.gfp_mask = GFP_HIGHUSER_MOVABLE,
@@ -3940,8 +3939,7 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim) 


	fs_reclaim_acquire(sc.gfp_mask);

	noreclaim_flag = memalloc_noreclaim_save();

	reclaim_state.reclaimed_slab = 0;

	p->reclaim_state = &reclaim_state;

	p->reclaim_state = &sc.reclaim_state;



	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
@@ -4110,7 +4108,6 @@ static int __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned in 
	/* Minimum pages needed in order to stay on node */

	const unsigned long nr_pages = 1 << order;

	struct task_struct *p = current;

	struct reclaim_state reclaim_state;

	unsigned int noreclaim_flag;

	struct scan_control sc = {

		.nr_to_reclaim = max(nr_pages, SWAP_CLUSTER_MAX),
@@ -4135,8 +4132,7 @@ static int __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned in 
	 */

	noreclaim_flag = memalloc_noreclaim_save();

	p->flags |= PF_SWAPWRITE;

	reclaim_state.reclaimed_slab = 0;

	p->reclaim_state = &reclaim_state;

	p->reclaim_state = &sc.reclaim_state;



	if (node_pagecache_reclaimable(pgdat) > pgdat->min_unmapped_pages) {

		/*

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