diff mbox series

[RFC,2/2] mm: swap: add comment for swap_vma_readahead

Message ID 1545115948-25467-2-git-send-email-yang.shi@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series [RFC,1/2] mm: swap: check if swap backing device is congested or not | expand

Commit Message

Yang Shi Dec. 18, 2018, 6:52 a.m. UTC 
swap_vma_readahead()'s comment is missed, just add it.

Cc: Huang Ying <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
---
 mm/swap_state.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
diff mbox series

Patch

diff --git a/mm/swap_state.c b/mm/swap_state.c
index 7cc3c29..c12aedf 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -695,6 +695,23 @@  static void swap_ra_info(struct vm_fault *vmf,
 	pte_unmap(orig_pte);
 }
 
+/**
+ * swap_vm_readahead - swap in pages in hope we need them soon
+ * @entry: swap entry of this memory
+ * @gfp_mask: memory allocation flags
+ * @vmf: fault information
+ *
+ * Returns the struct page for entry and addr, after queueing swapin.
+ *
+ * Primitive swap readahead code. We simply read in a few pages whoes
+ * virtual addresses are around the fault address in the same vma.
+ *
+ * This has been extended to use the NUMA policies from the mm triggering
+ * the readahead.
+ *
+ * Caller must hold down_read on the vma->vm_mm if vmf->vma is not NULL.
+ *
+ */
 static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask,
 				       struct vm_fault *vmf)
 {