Commit e9f59873 authored by Yang Shi's avatar Yang Shi Committed by Linus Torvalds

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.comSigned-off-by: default avatarYang Shi <yang.shi@linux.alibaba.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Hugh Dickins <hughd@google.com
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8fd2e0b5
...@@ -523,7 +523,7 @@ static unsigned long swapin_nr_pages(unsigned long offset) ...@@ -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 * This has been extended to use the NUMA policies from the mm triggering
* the readahead. * 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 page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
struct vm_fault *vmf) struct vm_fault *vmf)
...@@ -698,6 +698,20 @@ static void swap_ra_info(struct vm_fault *vmf, ...@@ -698,6 +698,20 @@ static void swap_ra_info(struct vm_fault *vmf,
pte_unmap(orig_pte); 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, static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask,
struct vm_fault *vmf) struct vm_fault *vmf)
{ {
......
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