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mm: Convert add_to_swap_cache to XArray 

Combine __add_to_swap_cache and add_to_swap_cache into one function
since there is no more need to preload.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
This commit is contained in:
Matthew Wilcox 2017-11-27 15:46:54 -05:00
parent 69b6c1319b
commit 8d93b41c09
1 changed files with 29 additions and 64 deletions
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93
mm/swap_state.c
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@ -107,14 +107,15 @@ void show_swap_cache_info(void)
}
/*
* __add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,
* add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,
* but sets SwapCache flag and private instead of mapping and index.
*/
int __add_to_swap_cache(struct page *page, swp_entry_t entry)
int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp)
{
int error, i, nr = hpage_nr_pages(page);
struct address_space *address_space;
struct address_space *address_space = swap_address_space(entry);
pgoff_t idx = swp_offset(entry);
XA_STATE_ORDER(xas, &address_space->i_pages, idx, compound_order(page));
unsigned long i, nr = 1UL << compound_order(page);
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(PageSwapCache(page), page);
@ -123,50 +124,30 @@ int __add_to_swap_cache(struct page *page, swp_entry_t entry)
page_ref_add(page, nr);
SetPageSwapCache(page);
address_space = swap_address_space(entry);
xa_lock_irq(&address_space->i_pages);
for (i = 0; i < nr; i++) {
set_page_private(page + i, entry.val + i);
error = radix_tree_insert(&address_space->i_pages,
idx + i, page + i);
if (unlikely(error))
break;
}
if (likely(!error)) {
do {
xas_lock_irq(&xas);
xas_create_range(&xas);
if (xas_error(&xas))
goto unlock;
for (i = 0; i < nr; i++) {
VM_BUG_ON_PAGE(xas.xa_index != idx + i, page);
set_page_private(page + i, entry.val + i);
xas_store(&xas, page + i);
xas_next(&xas);
}
address_space->nrpages += nr;
__mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr);
ADD_CACHE_INFO(add_total, nr);
} else {
/*
* Only the context which have set SWAP_HAS_CACHE flag
* would call add_to_swap_cache().
* So add_to_swap_cache() doesn't returns -EEXIST.
*/
VM_BUG_ON(error == -EEXIST);
set_page_private(page + i, 0UL);
while (i--) {
radix_tree_delete(&address_space->i_pages, idx + i);
set_page_private(page + i, 0UL);
}
ClearPageSwapCache(page);
page_ref_sub(page, nr);
}
xa_unlock_irq(&address_space->i_pages);
unlock:
xas_unlock_irq(&xas);
} while (xas_nomem(&xas, gfp));
return error;
}
if (!xas_error(&xas))
return 0;
int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask)
{
int error;
error = radix_tree_maybe_preload_order(gfp_mask, compound_order(page));
if (!error) {
error = __add_to_swap_cache(page, entry);
radix_tree_preload_end();
}
return error;
ClearPageSwapCache(page);
page_ref_sub(page, nr);
return xas_error(&xas);
}
/*
@ -217,7 +198,7 @@ int add_to_swap(struct page *page)
return 0;
/*
* Radix-tree node allocations from PF_MEMALLOC contexts could
* XArray node allocations from PF_MEMALLOC contexts could
* completely exhaust the page allocator. __GFP_NOMEMALLOC
* stops emergency reserves from being allocated.
*
@ -229,7 +210,6 @@ int add_to_swap(struct page *page)
*/
err = add_to_swap_cache(page, entry,
__GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN);
/* -ENOMEM radix-tree allocation failure */
if (err)
/*
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
@ -413,19 +393,11 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
break; /* Out of memory */
}
/*
* call radix_tree_preload() while we can wait.
*/
err = radix_tree_maybe_preload(gfp_mask & GFP_KERNEL);
if (err)
break;
/*
* Swap entry may have been freed since our caller observed it.
*/
err = swapcache_prepare(entry);
if (err == -EEXIST) {
radix_tree_preload_end();
/*
* We might race against get_swap_page() and stumble
* across a SWAP_HAS_CACHE swap_map entry whose page
@ -433,26 +405,19 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
*/
cond_resched();
continue;
}
if (err) { /* swp entry is obsolete ? */
radix_tree_preload_end();
} else if (err) /* swp entry is obsolete ? */
break;
}
/* May fail (-ENOMEM) if radix-tree node allocation failed. */
/* May fail (-ENOMEM) if XArray node allocation failed. */
__SetPageLocked(new_page);
__SetPageSwapBacked(new_page);
err = __add_to_swap_cache(new_page, entry);
err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL);
if (likely(!err)) {
radix_tree_preload_end();
/*
* Initiate read into locked page and return.
*/
/* Initiate read into locked page */
lru_cache_add_anon(new_page);
*new_page_allocated = true;
return new_page;
}
radix_tree_preload_end();
__ClearPageLocked(new_page);
/*
* add_to_swap_cache() doesn't return -EEXIST, so we can safely