From e9f598730ea0dde3b45560766240503367c404b7 Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Tue, 5 Mar 2019 15:44:15 -0800 Subject: mm: swap: add comment for swap_vma_readahead swap_vma_readahead()'s comment is missing, just add it. Link: http://lkml.kernel.org/r/1546543673-108536-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi Reviewed-by: Andrew Morton Cc: Huang Ying Cc: Tim Chen Cc: Minchan Kim Cc: Daniel Jordan Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/swap_state.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'mm/swap_state.c') diff --git a/mm/swap_state.c b/mm/swap_state.c index 56a3cc4f1068..85245fdec8d9 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -523,7 +523,7 @@ static unsigned long swapin_nr_pages(unsigned long offset) * 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. + * Caller must hold read mmap_sem if vmf->vma is not NULL. */ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, struct vm_fault *vmf) @@ -698,6 +698,20 @@ static void swap_ra_info(struct vm_fault *vmf, pte_unmap(orig_pte); } +/** + * swap_vma_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. + * + * Caller must hold read mmap_sem if vmf->vma is not NULL. + * + */ static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask, struct vm_fault *vmf) { -- cgit v1.2.3-59-g8ed1b