diff options
Diffstat (limited to 'mm/swap_state.c')
| -rw-r--r-- | mm/swap_state.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c index fd2f21e1c60a..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) @@ -543,6 +543,13 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, if (!mask) goto skip; + /* Test swap type to make sure the dereference is safe */ + if (likely(si->flags & (SWP_BLKDEV | SWP_FS))) { + struct inode *inode = si->swap_file->f_mapping->host; + if (inode_read_congested(inode)) + goto skip; + } + do_poll = false; /* Read a page_cluster sized and aligned cluster around offset. */ start_offset = offset & ~mask; @@ -691,6 +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) { |