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Code Issues Releases Wiki Activity

mm: convert do_swap_page() to use a folio 

Removes quite a lot of calls to compound_head().

Link: https://lkml.kernel.org/r/20220902194653.1739778-15-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-09-02 20:46:10 +01:00 committed by Andrew Morton
parent 4081f7446d
commit 63ad4add38
1 changed files with 33 additions and 24 deletions
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57
mm/memory.c
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@ -3724,6 +3724,7 @@ static vm_fault_t handle_pte_marker(struct vm_fault *vmf)
vm_fault_t do_swap_page(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct folio *folio;
struct page *page = NULL, *swapcache;
struct swap_info_struct *si = NULL;
rmap_t rmap_flags = RMAP_NONE;
@ -3768,19 +3769,23 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
page = lookup_swap_cache(entry, vma, vmf->address);
swapcache = page;
if (page)
folio = page_folio(page);
if (!page) {
if (data_race(si->flags & SWP_SYNCHRONOUS_IO) &&
__swap_count(entry) == 1) {
/* skip swapcache */
page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma,
vmf->address);
if (page) {
__SetPageLocked(page);
__SetPageSwapBacked(page);
folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0,
vma, vmf->address, false);
page = &folio->page;
if (folio) {
__folio_set_locked(folio);
__folio_set_swapbacked(folio);
if (mem_cgroup_swapin_charge_page(page,
vma->vm_mm, GFP_KERNEL, entry)) {
vma->vm_mm, GFP_KERNEL,
entry)) {
ret = VM_FAULT_OOM;
goto out_page;
}
@ -3788,20 +3793,21 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
shadow = get_shadow_from_swap_cache(entry);
if (shadow)
workingset_refault(page_folio(page),
shadow);
workingset_refault(folio, shadow);
lru_cache_add(page);
folio_add_lru(folio);
/* To provide entry to swap_readpage() */
set_page_private(page, entry.val);
folio_set_swap_entry(folio, entry);
swap_readpage(page, true, NULL);
set_page_private(page, 0);
folio->private = NULL;
}
} else {
page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE,
vmf);
swapcache = page;
if (page)
folio = page_folio(page);
}
if (!page) {
@ -3844,7 +3850,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
* swapcache, we need to check that the page's swap has not
* changed.
*/
if (unlikely(!PageSwapCache(page) ||
if (unlikely(!folio_test_swapcache(folio) ||
page_private(page) != entry.val))
goto out_page;
@ -3859,6 +3865,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
page = swapcache;
goto out_page;
}
folio = page_folio(page);
/*
* If we want to map a page that's in the swapcache writable, we
@ -3867,7 +3874,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
* pagevecs if required.
*/
if ((vmf->flags & FAULT_FLAG_WRITE) && page == swapcache &&
!PageKsm(page) && !PageLRU(page))
!folio_test_ksm(folio) && !folio_test_lru(folio))
lru_add_drain();
}
@ -3881,7 +3888,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte)))
goto out_nomap;
if (unlikely(!PageUptodate(page))) {
if (unlikely(!folio_test_uptodate(folio))) {
ret = VM_FAULT_SIGBUS;
goto out_nomap;
}
@ -3894,14 +3901,14 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
* check after taking the PT lock and making sure that nobody
* concurrently faulted in this page and set PG_anon_exclusive.
*/
BUG_ON(!PageAnon(page) && PageMappedToDisk(page));
BUG_ON(PageAnon(page) && PageAnonExclusive(page));
BUG_ON(!folio_test_anon(folio) && folio_test_mappedtodisk(folio));
BUG_ON(folio_test_anon(folio) && PageAnonExclusive(page));
/*
* Check under PT lock (to protect against concurrent fork() sharing
* the swap entry concurrently) for certainly exclusive pages.
*/
if (!PageKsm(page)) {
if (!folio_test_ksm(folio)) {
/*
* Note that pte_swp_exclusive() == false for architectures
* without __HAVE_ARCH_PTE_SWP_EXCLUSIVE.
@ -3913,7 +3920,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
* swapcache -> certainly exclusive.
*/
exclusive = true;
} else if (exclusive && PageWriteback(page) &&
} else if (exclusive && folio_test_writeback(folio) &&
data_race(si->flags & SWP_STABLE_WRITES)) {
/*
* This is tricky: not all swap backends support
@ -3956,7 +3963,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
* exposing them to the swapcache or because the swap entry indicates
* exclusivity.
*/
if (!PageKsm(page) && (exclusive || page_count(page) == 1)) {
if (!folio_test_ksm(folio) &&
(exclusive || folio_ref_count(folio) == 1)) {
if (vmf->flags & FAULT_FLAG_WRITE) {
pte = maybe_mkwrite(pte_mkdirty(pte), vma);
vmf->flags &= ~FAULT_FLAG_WRITE;
@ -3976,16 +3984,17 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
/* ksm created a completely new copy */
if (unlikely(page != swapcache && swapcache)) {
page_add_new_anon_rmap(page, vma, vmf->address);
lru_cache_add_inactive_or_unevictable(page, vma);
folio_add_lru_vma(folio, vma);
} else {
page_add_anon_rmap(page, vma, vmf->address, rmap_flags);
}
VM_BUG_ON(!PageAnon(page) || (pte_write(pte) && !PageAnonExclusive(page)));
VM_BUG_ON(!folio_test_anon(folio) ||
(pte_write(pte) && !PageAnonExclusive(page)));
set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte);
arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte);
unlock_page(page);
folio_unlock(folio);
if (page != swapcache && swapcache) {
/*
* Hold the lock to avoid the swap entry to be reused
@ -4017,9 +4026,9 @@ out:
out_nomap:
pte_unmap_unlock(vmf->pte, vmf->ptl);
out_page:
unlock_page(page);
folio_unlock(folio);
out_release:
put_page(page);
folio_put(folio);
if (page != swapcache && swapcache) {
unlock_page(swapcache);
put_page(swapcache);