Commit bb98f2c5 authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds
Browse files

mm, memcontrol: move swap charge handling into get_swap_page() 

Patch series "mm, memcontrol: Implement memory.swap.events", v2.

This patchset implements memory.swap.events which contains max and fail
events so that userland can monitor and respond to swap running out.

This patch (of 2):

get_swap_page() is always followed by mem_cgroup_try_charge_swap().
This patch moves mem_cgroup_try_charge_swap() into get_swap_page() and
makes get_swap_page() call the function even after swap allocation
failure.

This simplifies the callers and consolidates memcg related logic and
will ease adding swap related memcg events.

Link: http://lkml.kernel.org/r/20180416230934.GH1911913@devbig577.frc2.facebook.com


Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 88aa7cc6

mm/memcontrol.c

+3 −0
Original line number Diff line number Diff line
@@ -6012,6 +6012,9 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry) 
	if (!memcg)

		return 0;



	if (!entry.val)

		return 0;



	memcg = mem_cgroup_id_get_online(memcg);



	if (!mem_cgroup_is_root(memcg) &&

mm/shmem.c

+0 −4
Original line number Diff line number Diff line
@@ -1322,9 +1322,6 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) 
	if (!swap.val)

		goto redirty;



	if (mem_cgroup_try_charge_swap(page, swap))

		goto free_swap;



	/*

	 * Add inode to shmem_unuse()'s list of swapped-out inodes,

	 * if it's not already there.  Do it now before the page is
@@ -1353,7 +1350,6 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) 
	}



	mutex_unlock(&shmem_swaplist_mutex);

free_swap:

	put_swap_page(page, swap);

redirty:

	set_page_dirty(page);

mm/swap_slots.c

+7 −3
Original line number Diff line number Diff line
@@ -317,7 +317,7 @@ swp_entry_t get_swap_page(struct page *page) 
	if (PageTransHuge(page)) {

		if (IS_ENABLED(CONFIG_THP_SWAP))

			get_swap_pages(1, true, &entry);

		return entry;

		goto out;

	}



	/*
@@ -347,10 +347,14 @@ repeat: 
		}

		mutex_unlock(&cache->alloc_lock);

		if (entry.val)

			return entry;

			goto out;

	}



	get_swap_pages(1, false, &entry);



out:

	if (mem_cgroup_try_charge_swap(page, entry)) {

		put_swap_page(page, entry);

		entry.val = 0;

	}

	return entry;

}

mm/swap_state.c

+0 −3
Original line number Diff line number Diff line
@@ -216,9 +216,6 @@ int add_to_swap(struct page *page) 
	if (!entry.val)

		return 0;



	if (mem_cgroup_try_charge_swap(page, entry))

		goto fail;



	/*

	 * Radix-tree node allocations from PF_MEMALLOC contexts could

	 * completely exhaust the page allocator. __GFP_NOMEMALLOC

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