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| author |   Yang Shi <yang.shi@linux.alibaba.com> | 2019-03-05 15:44:15 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-05 21:07:16 -0800 |
| commit | e9f598730ea0dde3b45560766240503367c404b7 (patch) | |
| tree | cd91c28dcbff90c3f8950a7551db34987bcbe5c6 | |
| parent | mm: swap: check if swap backing device is congested or not (diff) | |
| download | linux-dev-e9f598730ea0dde3b45560766240503367c404b7.tar.xz linux-dev-e9f598730ea0dde3b45560766240503367c404b7.zip | |
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 <yang.shi@linux.alibaba.com>
Reviewed-by: Andrew 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/swap_state.c | 16 |
1 files changed, 15 insertions, 1 deletions
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) { |