2023-09-15 21:54:12

by Pankaj Raghav (Samsung)

Subject: [RFC 06/23] mm: call xas_set_order() in replace_page_cache_folio()

From: Luis Chamberlain <[email protected]>

Call xas_set_order() in replace_page_cache_folio() for non hugetlb
pages.

Signed-off-by: Luis Chamberlain <[email protected]>
---
mm/filemap.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/mm/filemap.c b/mm/filemap.c
index 4dee24b5b61c..33de71bfa953 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -815,12 +815,14 @@ EXPORT_SYMBOL(file_write_and_wait_range);
void replace_page_cache_folio(struct folio *old, struct folio *new)
{
struct address_space *mapping = old->mapping;
+ unsigned int min_order = mapping_min_folio_order(mapping);
void (*free_folio)(struct folio *) = mapping->a_ops->free_folio;
pgoff_t offset = old->index;
XA_STATE(xas, &mapping->i_pages, offset);

VM_BUG_ON_FOLIO(!folio_test_locked(old), old);
VM_BUG_ON_FOLIO(!folio_test_locked(new), new);
+ VM_BUG_ON_FOLIO(folio_order(new) != folio_order(old), new);
VM_BUG_ON_FOLIO(new->mapping, new);

folio_get(new);
@@ -829,6 +831,11 @@ void replace_page_cache_folio(struct folio *old, struct folio *new)

mem_cgroup_migrate(old, new);

+ if (!folio_test_hugetlb(new)) {
+ VM_BUG_ON_FOLIO(folio_order(new) < min_order, new);
+ xas_set_order(&xas, offset, folio_order(new));
+ }
+
xas_lock_irq(&xas);
xas_store(&xas, new);

--
2.40.1

2023-09-15 22:11:19

by Matthew Wilcox

Subject: Re: [RFC 06/23] mm: call xas_set_order() in replace_page_cache_folio()

On Fri, Sep 15, 2023 at 08:38:31PM +0200, Pankaj Raghav wrote:
> From: Luis Chamberlain <[email protected]>
>
> Call xas_set_order() in replace_page_cache_folio() for non hugetlb
> pages.

This function definitely should work without this patch. What goes wrong?

> Signed-off-by: Luis Chamberlain <[email protected]>
> ---
> mm/filemap.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 4dee24b5b61c..33de71bfa953 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -815,12 +815,14 @@ EXPORT_SYMBOL(file_write_and_wait_range);
> void replace_page_cache_folio(struct folio *old, struct folio *new)
> {
> struct address_space *mapping = old->mapping;
> + unsigned int min_order = mapping_min_folio_order(mapping);
> void (*free_folio)(struct folio *) = mapping->a_ops->free_folio;
> pgoff_t offset = old->index;
> XA_STATE(xas, &mapping->i_pages, offset);
>
> VM_BUG_ON_FOLIO(!folio_test_locked(old), old);
> VM_BUG_ON_FOLIO(!folio_test_locked(new), new);
> + VM_BUG_ON_FOLIO(folio_order(new) != folio_order(old), new);
> VM_BUG_ON_FOLIO(new->mapping, new);
>
> folio_get(new);
> @@ -829,6 +831,11 @@ void replace_page_cache_folio(struct folio *old, struct folio *new)
>
> mem_cgroup_migrate(old, new);
>
> + if (!folio_test_hugetlb(new)) {
> + VM_BUG_ON_FOLIO(folio_order(new) < min_order, new);
> + xas_set_order(&xas, offset, folio_order(new));
> + }
> +
> xas_lock_irq(&xas);
> xas_store(&xas, new);
>
> --
> 2.40.1
>

2023-09-19 03:14:06

by Luis Chamberlain

Subject: Re: [RFC 06/23] mm: call xas_set_order() in replace_page_cache_folio()

On Fri, Sep 15, 2023 at 08:46:10PM +0100, Matthew Wilcox wrote:
> On Fri, Sep 15, 2023 at 08:38:31PM +0200, Pankaj Raghav wrote:
> > From: Luis Chamberlain <[email protected]>
> >
> > Call xas_set_order() in replace_page_cache_folio() for non hugetlb
> > pages.
>
> This function definitely should work without this patch. What goes wrong?

As with batch delete I was just trying to take care to be explicit about
setting the order for a) ddition and b) removal. Will drop as well after
confirming, thanks!

Luis