diff options
| author | Hugh Dickins <hugh@veritas.com> | 2007-07-19 01:49:11 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-19 10:04:50 -0700 |
| commit | 7ed5cb2b73d0c4165c0504c95454fade0c0bf3d9 (patch) | |
| tree | 37b15b57986466531c5a0debb6b52660ca47e86a | |
| parent | e3aded3cc289113c7bc729ef4cb75e56d9aa71be (diff) | |
Remove nid_lock from alloc_fresh_huge_page
The fix to that race in alloc_fresh_huge_page() which could give an illegal
node ID did not need nid_lock at all: the fix was to replace static int nid
by static int prev_nid and do the work on local int nid. nid_lock did make
sure that racers strictly roundrobin the nodes, but that's not something we
need to enforce strictly. Kill nid_lock.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/hugetlb.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 15fc7b00077..2d7611cf276 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -104,15 +104,19 @@ static int alloc_fresh_huge_page(void) { static int prev_nid; struct page *page; - static DEFINE_SPINLOCK(nid_lock); int nid; - spin_lock(&nid_lock); + /* + * Copy static prev_nid to local nid, work on that, then copy it + * back to prev_nid afterwards: otherwise there's a window in which + * a racer might pass invalid nid MAX_NUMNODES to alloc_pages_node. + * But we don't need to use a spin_lock here: it really doesn't + * matter if occasionally a racer chooses the same nid as we do. + */ nid = next_node(prev_nid, node_online_map); if (nid == MAX_NUMNODES) nid = first_node(node_online_map); prev_nid = nid; - spin_unlock(&nid_lock); page = alloc_pages_node(nid, htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN, HUGETLB_PAGE_ORDER); |