Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f116695a authored by Sasha Levin's avatar Sasha Levin Committed by Konrad Rzeszutek Wilk
Browse files

mm: frontswap: split out __frontswap_unuse_pages 



An attempt at making frontswap_shrink shorter and more readable. This patch
splits out walking through the swap list to find an entry with enough
pages to unuse.

Also, assert that the internal __frontswap_unuse_pages is called under swap
lock, since that part of code was previously directly happen inside the lock.

Signed-off-by: default avatarSasha Levin <levinsasha928@gmail.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 96253444

mm/frontswap.c

+39 −20
Original line number Diff line number Diff line
@@ -230,6 +230,41 @@ static unsigned long __frontswap_curr_pages(void) 
	return totalpages;

}



static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused,

					int *swapid)

{

	int ret = -EINVAL;

	struct swap_info_struct *si = NULL;

	int si_frontswap_pages;

	unsigned long total_pages_to_unuse = total;

	unsigned long pages = 0, pages_to_unuse = 0;

	int type;



	assert_spin_locked(&swap_lock);

	for (type = swap_list.head; type >= 0; type = si->next) {

		si = swap_info[type];

		si_frontswap_pages = atomic_read(&si->frontswap_pages);

		if (total_pages_to_unuse < si_frontswap_pages) {

			pages = pages_to_unuse = total_pages_to_unuse;

		} else {

			pages = si_frontswap_pages;

			pages_to_unuse = 0; /* unuse all */

		}

		/* ensure there is enough RAM to fetch pages from frontswap */

		if (security_vm_enough_memory_mm(current->mm, pages)) {

			ret = -ENOMEM;

			continue;

		}

		vm_unacct_memory(pages);

		*unused = pages_to_unuse;

		*swapid = type;

		ret = 0;

		break;

	}



	return ret;

}



/*

 * Frontswap, like a true swap device, may unnecessarily retain pages

 * under certain circumstances; "shrink" frontswap is essentially a
@@ -240,11 +275,9 @@ static unsigned long __frontswap_curr_pages(void) 
 */

void frontswap_shrink(unsigned long target_pages)

{

	struct swap_info_struct *si = NULL;

	int si_frontswap_pages;

	unsigned long total_pages = 0, total_pages_to_unuse;

	unsigned long pages = 0, pages_to_unuse = 0;

	int type;

	unsigned long pages_to_unuse = 0;

	int type, ret;

	bool locked = false;



	/*
@@ -258,22 +291,8 @@ void frontswap_shrink(unsigned long target_pages) 
	if (total_pages <= target_pages)

		goto out;

	total_pages_to_unuse = total_pages - target_pages;

	for (type = swap_list.head; type >= 0; type = si->next) {

		si = swap_info[type];

		si_frontswap_pages = atomic_read(&si->frontswap_pages);

		if (total_pages_to_unuse < si_frontswap_pages) {

			pages = pages_to_unuse = total_pages_to_unuse;

		} else {

			pages = si_frontswap_pages;

			pages_to_unuse = 0; /* unuse all */

		}

		/* ensure there is enough RAM to fetch pages from frontswap */

		if (security_vm_enough_memory_mm(current->mm, pages))

			continue;

		vm_unacct_memory(pages);

		break;

	}

	if (type < 0)

	ret = __frontswap_unuse_pages(total_pages_to_unuse, &pages_to_unuse, &type);

	if (ret < 0)

		goto out;

	locked = false;

	spin_unlock(&swap_lock);