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 23955622ff8d ("swap: add block io poll in swapin path")
[2] Commit 9650b453a3d4 ("block: ignore RWF_HIPRI hint for sync dio")
[3] Commit b243dcbf2f13 ("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: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index edd987f1bd8c3ed1c52365ff323c3537d18b4544..44a81d737f1ea8fa28c8b17508d305df0e80d71e 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -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 {

diff --git a/mm/page_io.c b/mm/page_io.c
index 41e8d738c6d28549568afe251a15bbc113ab5007..f1a9cfab6e74864511b1b23b42cd60f021d1979d 100644 (file)
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -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);

diff --git a/mm/swap.h b/mm/swap.h
index 2c0e96272d498ddfdfc0383f0132a6714c69e8c1..baa1fa946b347b3464962283160f8bd9cf6e9bf0 100644 (file)
--- a/mm/swap.h
+++ b/mm/swap.h
@@ -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)

diff --git a/mm/swap_state.c b/mm/swap_state.c
index 0803eedeabe3d8c51360699069101a1c35d1731b..994723cef82171bc6e65749f2f9609cb9eabd1ba 100644 (file)
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -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 @@ skip:
                                        &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 @@ skip:
                                        &page_allocated, false);
        if (unlikely(page_allocated)) {
                zswap_folio_swapin(folio);
-               swap_read_folio(folio, false, NULL);
+               swap_read_folio(folio, NULL);
        }
        return folio;
 }