mm: swap: clean up swap readahead
When I see recent change of swap readahead, I am very unhappy about
current code structure which diverges two swap readahead algorithm in
do_swap_page. This patch is to clean it up.
Main motivation is that fault handler doesn't need to be aware of
readahead algorithms but just should call swapin_readahead.
As first step, this patch cleans up a little bit but not perfect (I just
separate for review easier) so next patch will make the goal complete.
[minchan@kernel.org: do not check readahead flag with THP anon]
Link: http://lkml.kernel.org/r/874lm83zho.fsf@yhuang-dev.intel.com
Link: http://lkml.kernel.org/r/20180227232611.169883-1-minchan@kernel.org
Link: http://lkml.kernel.org/r/1509520520-32367-2-git-send-email-minchan@kernel.org
Link: http://lkml.kernel.org/r/20180220085249.151400-2-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory.c b/mm/memory.c
index aed3732..bc1ccff 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2883,26 +2883,16 @@ EXPORT_SYMBOL(unmap_mapping_range);
int do_swap_page(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
- struct page *page = NULL, *swapcache = NULL;
+ struct page *page = NULL, *swapcache;
struct mem_cgroup *memcg;
- struct vma_swap_readahead swap_ra;
swp_entry_t entry;
pte_t pte;
int locked;
int exclusive = 0;
int ret = 0;
- bool vma_readahead = swap_use_vma_readahead();
- if (vma_readahead) {
- page = swap_readahead_detect(vmf, &swap_ra);
- swapcache = page;
- }
-
- if (!pte_unmap_same(vma->vm_mm, vmf->pmd, vmf->pte, vmf->orig_pte)) {
- if (page)
- put_page(page);
+ if (!pte_unmap_same(vma->vm_mm, vmf->pmd, vmf->pte, vmf->orig_pte))
goto out;
- }
entry = pte_to_swp_entry(vmf->orig_pte);
if (unlikely(non_swap_entry(entry))) {
@@ -2928,11 +2918,8 @@ int do_swap_page(struct vm_fault *vmf)
delayacct_set_flag(DELAYACCT_PF_SWAPIN);
- if (!page) {
- page = lookup_swap_cache(entry, vma_readahead ? vma : NULL,
- vmf->address);
- swapcache = page;
- }
+ page = lookup_swap_cache(entry, vma, vmf->address);
+ swapcache = page;
if (!page) {
struct swap_info_struct *si = swp_swap_info(entry);
@@ -2949,9 +2936,9 @@ int do_swap_page(struct vm_fault *vmf)
swap_readpage(page, true);
}
} else {
- if (vma_readahead)
+ if (swap_use_vma_readahead())
page = do_swap_page_readahead(entry,
- GFP_HIGHUSER_MOVABLE, vmf, &swap_ra);
+ GFP_HIGHUSER_MOVABLE, vmf);
else
page = swapin_readahead(entry,
GFP_HIGHUSER_MOVABLE, vma, vmf->address);
@@ -2982,7 +2969,6 @@ int do_swap_page(struct vm_fault *vmf)
*/
ret = VM_FAULT_HWPOISON;
delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
- swapcache = page;
goto out_release;
}
