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author | Sasha Levin <levinsasha928@gmail.com> | 2012-06-10 14:51:03 +0400 |
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committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-06-11 23:31:33 +0400 |
commit | 69217b4cd044671b6dddcd9d33c8e4fdfd295ae3 (patch) | |
tree | d13dab9972d7541cca1b2fd81efcb332e3d4900d /mm/frontswap.c | |
parent | f116695a500cdd84cbeac68bc373e98ae729c24b (diff) | |
download | linux-69217b4cd044671b6dddcd9d33c8e4fdfd295ae3.tar.xz |
mm: frontswap: split frontswap_shrink further to simplify locking
Split frontswap_shrink to simplify the locking in the original code.
Also, assert that the function that was split still runs under the
swap spinlock.
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'mm/frontswap.c')
-rw-r--r-- | mm/frontswap.c | 36 |
1 files changed, 21 insertions, 15 deletions
diff --git a/mm/frontswap.c b/mm/frontswap.c index faa43b7eea6f..e6353d9151ee 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -265,6 +265,24 @@ static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused, return ret; } +static int __frontswap_shrink(unsigned long target_pages, + unsigned long *pages_to_unuse, + int *type) +{ + unsigned long total_pages = 0, total_pages_to_unuse; + + assert_spin_locked(&swap_lock); + + total_pages = __frontswap_curr_pages(); + if (total_pages <= target_pages) { + /* Nothing to do */ + *pages_to_unuse = 0; + return 0; + } + total_pages_to_unuse = total_pages - target_pages; + return __frontswap_unuse_pages(total_pages_to_unuse, pages_to_unuse, type); +} + /* * Frontswap, like a true swap device, may unnecessarily retain pages * under certain circumstances; "shrink" frontswap is essentially a @@ -275,10 +293,8 @@ static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused, */ void frontswap_shrink(unsigned long target_pages) { - unsigned long total_pages = 0, total_pages_to_unuse; unsigned long pages_to_unuse = 0; int type, ret; - bool locked = false; /* * we don't want to hold swap_lock while doing a very @@ -286,20 +302,10 @@ void frontswap_shrink(unsigned long target_pages) * so restart scan from swap_list.head each time */ spin_lock(&swap_lock); - locked = true; - total_pages = __frontswap_curr_pages(); - if (total_pages <= target_pages) - goto out; - total_pages_to_unuse = total_pages - target_pages; - ret = __frontswap_unuse_pages(total_pages_to_unuse, &pages_to_unuse, &type); - if (ret < 0) - goto out; - locked = false; + ret = __frontswap_shrink(target_pages, &pages_to_unuse, &type); spin_unlock(&swap_lock); - try_to_unuse(type, true, pages_to_unuse); -out: - if (locked) - spin_unlock(&swap_lock); + if (ret == 0 && pages_to_unuse) + try_to_unuse(type, true, pages_to_unuse); return; } EXPORT_SYMBOL(frontswap_shrink); |