Commit b2d1f38b authored by Yosry Ahmed's avatar Yosry Ahmed Committed by Andrew Morton
Browse files

mm: swap: remove 'synchronous' argument to swap_read_folio() 

Commit [1] introduced IO polling support duding swapin to reduce swap read
latency for block devices that can be polled.  However later commit [2]
removed polling support.  Commit [3] removed the remnants of polling
support from read_swap_cache_async() and __read_swap_cache_async(). 
However, it left behind some remnants in swap_read_folio(), the
'synchronous' argument.

swap_read_folio() reads the folio synchronously if synchronous=true or if
SWP_SYNCHRONOUS_IO is set in swap_info_struct.  The only caller that
passes synchronous=true is in do_swap_page() in the SWP_SYNCHRONOUS_IO
case.

Hence, the argument is redundant, it is only set to true when the swap
read would have been synchronous anyway. Remove it.

[1] Commit 23955622 ("swap: add block io poll in swapin path")
[2] Commit 9650b453 ("block: ignore RWF_HIPRI hint for sync dio")
[3] Commit b243dcbf ("swap: remove remnants of polling from read_swap_cache_async")

Link: https://lkml.kernel.org/r/20240607045515.1836558-1-yosryahmed@google.com


Signed-off-by: default avatarYosry Ahmed <yosryahmed@google.com>
Reviewed-by: default avatar"Huang, Ying" <ying.huang@intel.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 90b8fab5

mm/memory.c

+1 −1
Original line number Diff line number Diff line
@@ -4115,7 +4115,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) 


				/* To provide entry to swap_read_folio() */

				folio->swap = entry;

				swap_read_folio(folio, true, NULL);

				swap_read_folio(folio, NULL);

				folio->private = NULL;

			}

		} else {

mm/page_io.c

+3 −3
Original line number Diff line number Diff line
@@ -493,10 +493,10 @@ static void swap_read_folio_bdev_async(struct folio *folio, 
	submit_bio(bio);

}



void swap_read_folio(struct folio *folio, bool synchronous,

		struct swap_iocb **plug)

void swap_read_folio(struct folio *folio, struct swap_iocb **plug)

{

	struct swap_info_struct *sis = swp_swap_info(folio->swap);

	bool synchronous = sis->flags & SWP_SYNCHRONOUS_IO;

	bool workingset = folio_test_workingset(folio);

	unsigned long pflags;

	bool in_thrashing;
@@ -521,7 +521,7 @@ void swap_read_folio(struct folio *folio, bool synchronous, 
		folio_unlock(folio);

	} else if (data_race(sis->flags & SWP_FS_OPS)) {

		swap_read_folio_fs(folio, plug);

	} else if (synchronous || (sis->flags & SWP_SYNCHRONOUS_IO)) {

	} else if (synchronous) {

		swap_read_folio_bdev_sync(folio, sis);

	} else {

		swap_read_folio_bdev_async(folio, sis);

mm/swap.h

+2 −4
Original line number Diff line number Diff line
@@ -11,8 +11,7 @@ struct mempolicy; 
/* linux/mm/page_io.c */

int sio_pool_init(void);

struct swap_iocb;

void swap_read_folio(struct folio *folio, bool do_poll,

		struct swap_iocb **plug);

void swap_read_folio(struct folio *folio, struct swap_iocb **plug);

void __swap_read_unplug(struct swap_iocb *plug);

static inline void swap_read_unplug(struct swap_iocb *plug)

{
@@ -83,8 +82,7 @@ static inline unsigned int folio_swap_flags(struct folio *folio) 
}

#else /* CONFIG_SWAP */

struct swap_iocb;

static inline void swap_read_folio(struct folio *folio, bool do_poll,

		struct swap_iocb **plug)

static inline void swap_read_folio(struct folio *folio, struct swap_iocb **plug)

{

}

static inline void swap_write_unplug(struct swap_iocb *sio)

mm/swap_state.c

+5 −5
Original line number Diff line number Diff line
@@ -567,7 +567,7 @@ struct folio *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, 
	mpol_cond_put(mpol);



	if (page_allocated)

		swap_read_folio(folio, false, plug);

		swap_read_folio(folio, plug);

	return folio;

}
@@ -684,7 +684,7 @@ struct folio *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, 
		if (!folio)

			continue;

		if (page_allocated) {

			swap_read_folio(folio, false, &splug);

			swap_read_folio(folio, &splug);

			if (offset != entry_offset) {

				folio_set_readahead(folio);

				count_vm_event(SWAP_RA);
@@ -701,7 +701,7 @@ struct folio *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, 
					&page_allocated, false);

	if (unlikely(page_allocated)) {

		zswap_folio_swapin(folio);

		swap_read_folio(folio, false, NULL);

		swap_read_folio(folio, NULL);

	}

	return folio;

}
@@ -834,7 +834,7 @@ static struct folio *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask, 
		if (!folio)

			continue;

		if (page_allocated) {

			swap_read_folio(folio, false, &splug);

			swap_read_folio(folio, &splug);

			if (addr != vmf->address) {

				folio_set_readahead(folio);

				count_vm_event(SWAP_RA);
@@ -853,7 +853,7 @@ static struct folio *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask, 
					&page_allocated, false);

	if (unlikely(page_allocated)) {

		zswap_folio_swapin(folio);

		swap_read_folio(folio, false, NULL);

		swap_read_folio(folio, NULL);

	}

	return folio;

}