diff options
| author | H. Peter Anvin <hpa@linux.intel.com> | 2013-06-20 21:13:55 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2013-06-20 21:13:55 -0700 |
| commit | e6bca5a6a8a0cdc41a9e1e3e69bc8476ac6a8ed4 (patch) | |
| tree | 2651a8a7b81ee71113bdeda8425a2083f2842b20 /mm/swap_state.c | |
| parent | e8747f10ba3f7638b1c1fcab9c66a01733213d45 (diff) | |
| parent | 7d132055814ef17a6c7b69f342244c410a5e000f (diff) | |
Merge tag 'v3.10-rc6' into x86/cleanups
Linux 3.10-rc6
We need a change that is the mainline tree for further work.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'mm/swap_state.c')
| -rw-r--r-- | mm/swap_state.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c index b3d40dcf3624..f24ab0dff554 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -336,8 +336,24 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, * Swap entry may have been freed since our caller observed it. */ err = swapcache_prepare(entry); - if (err == -EEXIST) { /* seems racy */ + if (err == -EEXIST) { radix_tree_preload_end(); + /* + * We might race against get_swap_page() and stumble + * across a SWAP_HAS_CACHE swap_map entry whose page + * has not been brought into the swapcache yet, while + * the other end is scheduled away waiting on discard + * I/O completion at scan_swap_map(). + * + * In order to avoid turning this transitory state + * into a permanent loop around this -EEXIST case + * if !CONFIG_PREEMPT and the I/O completion happens + * to be waiting on the CPU waitqueue where we are now + * busy looping, we just conditionally invoke the + * scheduler here, if there are some more important + * tasks to run. + */ + cond_resched(); continue; } if (err) { /* swp entry is obsolete ? */ |