The patch titled
Subject: mm: shmem: return number of pages beeing freed in shmem_free_swap
has been added to the -mm mm-unstable branch. Its filename is
mm-shmem-return-number-of-pages-beeing-freed-in-shmem_free_swap.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-shmem-return-number-of-pages-beeing-freed-in-shmem_free_swap.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Daniel Gomez <da.gomez@xxxxxxxxxxx>
Subject: mm: shmem: return number of pages beeing freed in shmem_free_swap
Date: Tue, 18 Jun 2024 14:54:16 +0800
Both shmem_free_swap callers expect the number of pages being freed. In
the large folios context, this needs to support larger values other than 0
(used as 1 page being freed) and -ENOENT (used as 0 pages being freed).
In preparation for large folios adoption, make shmem_free_swap routine
return the number of pages being freed. So, returning 0 in this context,
means 0 pages being freed.
While we are at it, changing to use free_swap_and_cache_nr() to free large
order swap entry by Baolin Wang.
Link: https://lkml.kernel.org/r/6e567bfbb6bac0bfbdd63e60718bd1aaf8eade6c.1718690645.git.baolin.wang@xxxxxxxxxxxxxxxxx
Signed-off-by: Daniel Gomez <da.gomez@xxxxxxxxxxx>
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Suggested-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Barry Song <21cnbao@xxxxxxxxx>
Cc: Chris Li <chrisl@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Lance Yang <ioworker0@xxxxxxxxx>
Cc: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
--- a/mm/shmem.c~mm-shmem-return-number-of-pages-beeing-freed-in-shmem_free_swap
+++ a/mm/shmem.c
@@ -836,18 +836,22 @@ static void shmem_delete_from_page_cache
}
/*
- * Remove swap entry from page cache, free the swap and its page cache.
+ * Remove swap entry from page cache, free the swap and its page cache. Returns
+ * the number of pages being freed. 0 means entry not found in XArray (0 pages
+ * being freed).
*/
-static int shmem_free_swap(struct address_space *mapping,
- pgoff_t index, void *radswap)
+static long shmem_free_swap(struct address_space *mapping,
+ pgoff_t index, void *radswap)
{
+ int order = xa_get_order(&mapping->i_pages, index);
void *old;
old = xa_cmpxchg_irq(&mapping->i_pages, index, radswap, NULL, 0);
if (old != radswap)
- return -ENOENT;
- free_swap_and_cache(radix_to_swp_entry(radswap));
- return 0;
+ return 0;
+ free_swap_and_cache_nr(radix_to_swp_entry(radswap), 1 << order);
+
+ return 1 << order;
}
/*
@@ -999,7 +1003,7 @@ static void shmem_undo_range(struct inod
if (xa_is_value(folio)) {
if (unfalloc)
continue;
- nr_swaps_freed += !shmem_free_swap(mapping,
+ nr_swaps_freed += shmem_free_swap(mapping,
indices[i], folio);
continue;
}
@@ -1066,14 +1070,17 @@ whole_folios:
folio = fbatch.folios[i];
if (xa_is_value(folio)) {
+ long swaps_freed;
+
if (unfalloc)
continue;
- if (shmem_free_swap(mapping, indices[i], folio)) {
+ swaps_freed = shmem_free_swap(mapping, indices[i], folio);
+ if (!swaps_freed) {
/* Swap was replaced by page: retry */
index = indices[i];
break;
}
- nr_swaps_freed++;
+ nr_swaps_freed += swaps_freed;
continue;
}
_
Patches currently in -mm which might be from da.gomez@xxxxxxxxxxx are
mm-shmem-return-number-of-pages-beeing-freed-in-shmem_free_swap.patch
