Commit 54f7a49c authored by Barry Song's avatar Barry Song Committed by Andrew Morton
Browse files

mm: remove the implementation of swap_free() and always use swap_free_nr() 

To streamline maintenance efforts, we propose removing the implementation
of swap_free().  Instead, we can simply invoke swap_free_nr() with nr set
to 1.  swap_free_nr() is designed with a bitmap consisting of only one
long, resulting in overhead that can be ignored for cases where nr equals
1.

A prime candidate for leveraging swap_free_nr() lies within
kernel/power/swap.c.  Implementing this change facilitates the adoption of
batch processing for hibernation.

Link: https://lkml.kernel.org/r/20240529082824.150954-3-21cnbao@gmail.com


Signed-off-by: default avatarBarry Song <v-songbaohua@oppo.com>
Suggested-by: default avatar"Huang, Ying" <ying.huang@intel.com>
Reviewed-by: default avatar"Huang, Ying" <ying.huang@intel.com>
Acked-by: default avatarChris Li <chrisl@kernel.org>
Reviewed-by: default avatarRyan Roberts <ryan.roberts@arm.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent ebfba004

include/linux/swap.h

+5 −5
Original line number Diff line number Diff line
@@ -477,7 +477,6 @@ extern int add_swap_count_continuation(swp_entry_t, gfp_t); 
extern void swap_shmem_alloc(swp_entry_t);

extern int swap_duplicate(swp_entry_t);

extern int swapcache_prepare(swp_entry_t);

extern void swap_free(swp_entry_t);

extern void swap_free_nr(swp_entry_t entry, int nr_pages);

extern void swapcache_free_entries(swp_entry_t *entries, int n);

extern void free_swap_and_cache_nr(swp_entry_t entry, int nr);
@@ -556,10 +555,6 @@ static inline int swapcache_prepare(swp_entry_t swp) 
	return 0;

}



static inline void swap_free(swp_entry_t swp)

{

}



static inline void swap_free_nr(swp_entry_t entry, int nr_pages)

{

}
@@ -608,6 +603,11 @@ static inline void free_swap_and_cache(swp_entry_t entry) 
	free_swap_and_cache_nr(entry, 1);

}



static inline void swap_free(swp_entry_t entry)

{

	swap_free_nr(entry, 1);

}



#ifdef CONFIG_MEMCG

static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)

{

kernel/power/swap.c

+2 −3
Original line number Diff line number Diff line
@@ -200,12 +200,11 @@ void free_all_swap_pages(int swap) 


	while ((node = swsusp_extents.rb_node)) {

		struct swsusp_extent *ext;

		unsigned long offset;



		ext = rb_entry(node, struct swsusp_extent, node);

		rb_erase(node, &swsusp_extents);

		for (offset = ext->start; offset <= ext->end; offset++)

			swap_free(swp_entry(swap, offset));

		swap_free_nr(swp_entry(swap, ext->start),

			     ext->end - ext->start + 1);



		kfree(ext);

	}

mm/swapfile.c

+4 −13
Original line number Diff line number Diff line
@@ -1343,19 +1343,6 @@ static void swap_entry_free(struct swap_info_struct *p, swp_entry_t entry) 
	swap_range_free(p, offset, 1);

}



/*

 * Caller has made sure that the swap device corresponding to entry

 * is still around or has not been recycled.

 */

void swap_free(swp_entry_t entry)

{

	struct swap_info_struct *p;



	p = _swap_info_get(entry);

	if (p)

		__swap_entry_free(p, entry);

}



static void cluster_swap_free_nr(struct swap_info_struct *sis,

		unsigned long offset, int nr_pages)

{
@@ -1385,6 +1372,10 @@ static void cluster_swap_free_nr(struct swap_info_struct *sis, 
	unlock_cluster_or_swap_info(sis, ci);

}



/*

 * Caller has made sure that the swap device corresponding to entry

 * is still around or has not been recycled.

 */

void swap_free_nr(swp_entry_t entry, int nr_pages)

{

	int nr;