mm/swap: enable swap slots cache usage

Initialize swap slots cache and enable it on swap on.  Drain all swap
slots on swap off.

Link: http://lkml.kernel.org/r/07cbc94882fa95d4ac3cfc50b8dce0b1ec231b93.1484082593.git.tim.c.chen@linux.intel.com
Signed-off-by: Tim Chen <[email protected]>
Cc: "Huang, Ying" <[email protected]>
Cc: Aaron Lu <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Huang Ying <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Jonathan Corbet <[email protected]> escreveu:
Cc: Kirill A. Shutemov <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Shaohua Li <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 30a90fd140b7ae50928152db1f3436eb3b5fd54a..2cac12cc9abe2dbbd7e5e385de91cf93a4ab61d1 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2190,6 +2190,8 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
        spin_unlock(&p->lock);
        spin_unlock(&swap_lock);
 
+       disable_swap_slots_cache_lock();
+
        set_current_oom_origin();
        err = try_to_unuse(p->type, false, 0); /* force unuse all pages */
        clear_current_oom_origin();
@@ -2197,9 +2199,12 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
        if (err) {
                /* re-insert swap space back into swap_list */
                reinsert_swap_info(p);
+               reenable_swap_slots_cache_unlock();
                goto out_dput;
        }
 
+       reenable_swap_slots_cache_unlock();
+
        flush_work(&p->discard_work);
 
        destroy_swap_extents(p);
@@ -2886,6 +2891,8 @@ out:
                putname(name);
        if (inode && S_ISREG(inode->i_mode))
                inode_unlock(inode);
+       if (!error)
+               enable_swap_slots_cache();
        return error;
 }