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mm: return the folio from __read_swap_cache_async()

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Patch series "More swap folio conversions".

These all seem like fairly straightforward conversions to me.  A lot of
compound_head() calls get removed.  And page_swap_info(), which is nice.


This patch (of 13):

Move the folio->page conversion into the callers that actually want that. 
Most of the callers are happier with the folio anyway.  If the
page_allocated boolean is set, the folio allocated is of order-0, so it is
safe to pass the page directly to swap_readpage().

Link: https://lkml.kernel.org/r/20231213215842.671461-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20231213215842.671461-2-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) 2023-12-13 21:58:30 +00:00 committed by Andrew Morton
parent 8ba2f844f0
commit 96c7b0b422
4 changed files with 69 additions and 75 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/zswap.h
View File

@ -34,7 +34,7 @@ void zswap_swapon(int type);
void zswap_swapoff(int type);
void zswap_memcg_offline_cleanup(struct mem_cgroup *memcg);
void zswap_lruvec_state_init(struct lruvec *lruvec);
void zswap_page_swapin(struct page *page);
void zswap_folio_swapin(struct folio *folio);
#else
struct zswap_lruvec_state {};
@ -54,7 +54,7 @@ static inline void zswap_swapon(int type) {}
static inline void zswap_swapoff(int type) {}
static inline void zswap_memcg_offline_cleanup(struct mem_cgroup *memcg) {}
static inline void zswap_lruvec_state_init(struct lruvec *lruvec) {}
static inline void zswap_page_swapin(struct page *page) {}
static inline void zswap_folio_swapin(struct folio *folio) {}
#endif
#endif /* _LINUX_ZSWAP_H */

7
mm/swap.h
View File

@ -49,10 +49,9 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma,
unsigned long addr,
struct swap_iocb **plug);
struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct mempolicy *mpol, pgoff_t ilx,
bool *new_page_allocated,
bool skip_if_exists);
struct folio *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_flags,
struct mempolicy *mpol, pgoff_t ilx, bool *new_page_allocated,
bool skip_if_exists);
struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
struct mempolicy *mpol, pgoff_t ilx);
struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,

75
mm/swap_state.c
View File

@ -410,14 +410,12 @@ struct folio *filemap_get_incore_folio(struct address_space *mapping,
return folio;
}
struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct mempolicy *mpol, pgoff_t ilx,
bool *new_page_allocated,
bool skip_if_exists)
struct folio *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct mempolicy *mpol, pgoff_t ilx, bool *new_page_allocated,
bool skip_if_exists)
{
struct swap_info_struct *si;
struct folio *folio;
struct page *page;
void *shadow = NULL;
*new_page_allocated = false;
@ -434,10 +432,8 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
*/
folio = filemap_get_folio(swap_address_space(entry),
swp_offset(entry));
if (!IS_ERR(folio)) {
page = folio_file_page(folio, swp_offset(entry));
goto got_page;
}
if (!IS_ERR(folio))
goto got_folio;
/*
* Just skip read ahead for unused swap slot.
@ -451,7 +447,7 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
goto fail_put_swap;
/*
* Get a new page to read into from swap. Allocate it now,
* Get a new folio to read into from swap. Allocate it now,
* before marking swap_map SWAP_HAS_CACHE, when -EEXIST will
* cause any racers to loop around until we add it to cache.
*/
@ -487,13 +483,13 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
* stumble across a swap_map entry whose SWAP_HAS_CACHE
* has not yet been cleared. Or race against another
* __read_swap_cache_async(), which has set SWAP_HAS_CACHE
* in swap_map, but not yet added its page to swap cache.
* in swap_map, but not yet added its folio to swap cache.
*/
schedule_timeout_uninterruptible(1);
}
/*
* The swap entry is ours to swap in. Prepare the new page.
* The swap entry is ours to swap in. Prepare the new folio.
*/
__folio_set_locked(folio);
@ -514,10 +510,9 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
/* Caller will initiate read into locked folio */
folio_add_lru(folio);
*new_page_allocated = true;
page = &folio->page;
got_page:
got_folio:
put_swap_device(si);
return page;
return folio;
fail_unlock:
put_swap_folio(folio, entry);
@ -545,16 +540,16 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
bool page_allocated;
struct mempolicy *mpol;
pgoff_t ilx;
struct page *page;
struct folio *folio;
mpol = get_vma_policy(vma, addr, 0, &ilx);
page = __read_swap_cache_async(entry, gfp_mask, mpol, ilx,
folio = __read_swap_cache_async(entry, gfp_mask, mpol, ilx,
&page_allocated, false);
mpol_cond_put(mpol);
if (page_allocated)
swap_readpage(page, false, plug);
return page;
swap_readpage(&folio->page, false, plug);
return folio_file_page(folio, swp_offset(entry));
}
static unsigned int __swapin_nr_pages(unsigned long prev_offset,
@ -639,7 +634,7 @@ static unsigned long swapin_nr_pages(unsigned long offset)
struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
struct mempolicy *mpol, pgoff_t ilx)
{
struct page *page;
struct folio *folio;
unsigned long entry_offset = swp_offset(entry);
unsigned long offset = entry_offset;
unsigned long start_offset, end_offset;
@ -664,31 +659,31 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
blk_start_plug(&plug);
for (offset = start_offset; offset <= end_offset ; offset++) {
/* Ok, do the async read-ahead now */
page = __read_swap_cache_async(
folio = __read_swap_cache_async(
swp_entry(swp_type(entry), offset),
gfp_mask, mpol, ilx, &page_allocated, false);
if (!page)
if (!folio)
continue;
if (page_allocated) {
swap_readpage(page, false, &splug);
swap_readpage(&folio->page, false, &splug);
if (offset != entry_offset) {
SetPageReadahead(page);
folio_set_readahead(folio);
count_vm_event(SWAP_RA);
}
}
put_page(page);
folio_put(folio);
}
blk_finish_plug(&plug);
swap_read_unplug(splug);
lru_add_drain(); /* Push any new pages onto the LRU now */
skip:
/* The page was likely read above, so no need for plugging here */
page = __read_swap_cache_async(entry, gfp_mask, mpol, ilx,
folio = __read_swap_cache_async(entry, gfp_mask, mpol, ilx,
&page_allocated, false);
if (unlikely(page_allocated))
swap_readpage(page, false, NULL);
zswap_page_swapin(page);
return page;
swap_readpage(&folio->page, false, NULL);
zswap_folio_swapin(folio);
return folio_file_page(folio, swp_offset(entry));
}
int init_swap_address_space(unsigned int type, unsigned long nr_pages)
@ -806,7 +801,7 @@ static struct page *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask,
{
struct blk_plug plug;
struct swap_iocb *splug = NULL;
struct page *page;
struct folio *folio;
pte_t *pte = NULL, pentry;
unsigned long addr;
swp_entry_t entry;
@ -839,18 +834,18 @@ static struct page *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask,
continue;
pte_unmap(pte);
pte = NULL;
page = __read_swap_cache_async(entry, gfp_mask, mpol, ilx,
folio = __read_swap_cache_async(entry, gfp_mask, mpol, ilx,
&page_allocated, false);
if (!page)
if (!folio)
continue;
if (page_allocated) {
swap_readpage(page, false, &splug);
swap_readpage(&folio->page, false, &splug);
if (i != ra_info.offset) {
SetPageReadahead(page);
folio_set_readahead(folio);
count_vm_event(SWAP_RA);
}
}
put_page(page);
folio_put(folio);
}
if (pte)
pte_unmap(pte);
@ -858,13 +853,13 @@ static struct page *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask,
swap_read_unplug(splug);
lru_add_drain();
skip:
/* The page was likely read above, so no need for plugging here */
page = __read_swap_cache_async(targ_entry, gfp_mask, mpol, targ_ilx,
/* The folio was likely read above, so no need for plugging here */
folio = __read_swap_cache_async(targ_entry, gfp_mask, mpol, targ_ilx,
&page_allocated, false);
if (unlikely(page_allocated))
swap_readpage(page, false, NULL);
zswap_page_swapin(page);
return page;
swap_readpage(&folio->page, false, NULL);
zswap_folio_swapin(folio);
return folio_file_page(folio, swp_offset(entry));
}
/**

58
mm/zswap.c
View File

@ -368,12 +368,12 @@ void zswap_lruvec_state_init(struct lruvec *lruvec)
atomic_long_set(&lruvec->zswap_lruvec_state.nr_zswap_protected, 0);
}
void zswap_page_swapin(struct page *page)
void zswap_folio_swapin(struct folio *folio)
{
struct lruvec *lruvec;
if (page) {
lruvec = folio_lruvec(page_folio(page));
if (folio) {
lruvec = folio_lruvec(folio);
atomic_long_inc(&lruvec->zswap_lruvec_state.nr_zswap_protected);
}
}
@ -1383,14 +1383,14 @@ static void __zswap_load(struct zswap_entry *entry, struct page *page)
* writeback code
**********************************/
/*
* Attempts to free an entry by adding a page to the swap cache,
* decompressing the entry data into the page, and issuing a
* bio write to write the page back to the swap device.
* Attempts to free an entry by adding a folio to the swap cache,
* decompressing the entry data into the folio, and issuing a
* bio write to write the folio back to the swap device.
*
* This can be thought of as a "resumed writeback" of the page
* This can be thought of as a "resumed writeback" of the folio
* to the swap device. We are basically resuming the same swap
* writeback path that was intercepted with the zswap_store()
* in the first place. After the page has been decompressed into
* in the first place. After the folio has been decompressed into
* the swap cache, the compressed version stored by zswap can be
* freed.
*/
@ -1398,56 +1398,56 @@ static int zswap_writeback_entry(struct zswap_entry *entry,
struct zswap_tree *tree)
{
swp_entry_t swpentry = entry->swpentry;
struct page *page;
struct folio *folio;
struct mempolicy *mpol;
bool page_was_allocated;
bool folio_was_allocated;
struct writeback_control wbc = {
.sync_mode = WB_SYNC_NONE,
};
/* try to allocate swap cache page */
/* try to allocate swap cache folio */
mpol = get_task_policy(current);
page = __read_swap_cache_async(swpentry, GFP_KERNEL, mpol,
NO_INTERLEAVE_INDEX, &page_was_allocated, true);
if (!page)
folio = __read_swap_cache_async(swpentry, GFP_KERNEL, mpol,
NO_INTERLEAVE_INDEX, &folio_was_allocated, true);
if (!folio)
return -ENOMEM;
/*
* Found an existing page, we raced with load/swapin. We generally
* writeback cold pages from zswap, and swapin means the page just
* became hot. Skip this page and let the caller find another one.
* Found an existing folio, we raced with load/swapin. We generally
* writeback cold folios from zswap, and swapin means the folio just
* became hot. Skip this folio and let the caller find another one.
*/
if (!page_was_allocated) {
put_page(page);
if (!folio_was_allocated) {
folio_put(folio);
return -EEXIST;
}
/*
* Page is locked, and the swapcache is now secured against
* folio is locked, and the swapcache is now secured against
* concurrent swapping to and from the slot. Verify that the
* swap entry hasn't been invalidated and recycled behind our
* backs (our zswap_entry reference doesn't prevent that), to
* avoid overwriting a new swap page with old compressed data.
* avoid overwriting a new swap folio with old compressed data.
*/
spin_lock(&tree->lock);
if (zswap_rb_search(&tree->rbroot, swp_offset(entry->swpentry)) != entry) {
spin_unlock(&tree->lock);
delete_from_swap_cache(page_folio(page));
delete_from_swap_cache(folio);
return -ENOMEM;
}
spin_unlock(&tree->lock);
__zswap_load(entry, page);
__zswap_load(entry, &folio->page);
/* page is up to date */
SetPageUptodate(page);
/* folio is up to date */
folio_mark_uptodate(folio);
/* move it to the tail of the inactive list after end_writeback */
SetPageReclaim(page);
folio_set_reclaim(folio);
/* start writeback */
__swap_writepage(page, &wbc);
put_page(page);
__swap_writepage(&folio->page, &wbc);
folio_put(folio);
return 0;
}
@ -1593,7 +1593,7 @@ bool zswap_store(struct folio *folio)
dst = acomp_ctx->buffer;
sg_init_table(&input, 1);
sg_set_page(&input, page, PAGE_SIZE, 0);
sg_set_page(&input, &folio->page, PAGE_SIZE, 0);
/*
* We need PAGE_SIZE * 2 here since there maybe over-compression case,