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mm/swap: stop using page->private on tail pages for THP_SWAP

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Patch series "mm/swap: stop using page->private on tail pages for THP_SWAP
+ cleanups".

This series stops using page->private on tail pages for THP_SWAP, replaces
folio->private by folio->swap for swapcache folios, and starts using
"new_folio" for tail pages that we are splitting to remove the usage of
page->private for swapcache handling completely.


This patch (of 4):

Let's stop using page->private on tail pages, making it possible to just
unconditionally reuse that field in the tail pages of large folios.

The remaining usage of the private field for THP_SWAP is in the THP
splitting code (mm/huge_memory.c), that we'll handle separately later.

Update the THP_SWAP documentation and sanity checks in mm_types.h and
__split_huge_page_tail().

[david@redhat.com: stop using page->private on tail pages for THP_SWAP]
  Link: https://lkml.kernel.org/r/6f0a82a3-6948-20d9-580b-be1dbf415701@redhat.com
Link: https://lkml.kernel.org/r/20230821160849.531668-1-david@redhat.com
Link: https://lkml.kernel.org/r/20230821160849.531668-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
David Hildenbrand
2023-08-21 18:08:46 +02:00
committed by Andrew Morton
parent bad5a3a42a
commit cfeed8ffe5
8 changed files with 26 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
mm/swap_state.c
View File

@ -100,6 +100,7 @@ int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
folio_ref_add(folio, nr);
folio_set_swapcache(folio);
folio_set_swap_entry(folio, entry);
do {
xas_lock_irq(&xas);
@ -113,7 +114,6 @@ int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
if (shadowp)
*shadowp = old;
}
set_page_private(folio_page(folio, i), entry.val + i);
xas_store(&xas, folio);
xas_next(&xas);
}
@ -154,9 +154,10 @@ void __delete_from_swap_cache(struct folio *folio,
for (i = 0; i < nr; i++) {
void *entry = xas_store(&xas, shadow);
VM_BUG_ON_PAGE(entry != folio, entry);
set_page_private(folio_page(folio, i), 0);
xas_next(&xas);
}
entry.val = 0;
folio_set_swap_entry(folio, entry);
folio_clear_swapcache(folio);
address_space->nrpages -= nr;
__node_stat_mod_folio(folio, NR_FILE_PAGES, -nr);