* [PATCH 0/7] More folio compat code removal
@ 2024-04-24 19:19 Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 1/7] mm: Remove page_cache_alloc() Matthew Wilcox (Oracle)
` (6 more replies)
0 siblings, 7 replies; 10+ messages in thread
From: Matthew Wilcox (Oracle) @ 2024-04-24 19:19 UTC (permalink / raw
To: Andrew Morton; +Cc: Matthew Wilcox (Oracle), linux-mm
More code removal with bonus kernel-doc addition.
Matthew Wilcox (Oracle) (7):
mm: Remove page_cache_alloc()
mm: Remove put_devmap_managed_page()
mm: Convert put_devmap_managed_page_refs() to
put_devmap_managed_folio_refs()
mm: Remove page_ref_sub_return()
gup: Use folios for gup_devmap
mm: Add kernel-doc for folio_mark_accessed()
mm: Remove PageReferenced
include/linux/mm.h | 17 ++++++-----------
include/linux/page-flags.h | 6 +++---
include/linux/page_ref.h | 11 +++--------
include/linux/pagemap.h | 5 -----
mm/gup.c | 23 +++++++++++------------
mm/memremap.c | 10 +++++-----
mm/swap.c | 19 +++++++++++--------
7 files changed, 39 insertions(+), 52 deletions(-)
--
2.43.0
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH 1/7] mm: Remove page_cache_alloc()
2024-04-24 19:19 [PATCH 0/7] More folio compat code removal Matthew Wilcox (Oracle)
@ 2024-04-24 19:19 ` Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 2/7] mm: Remove put_devmap_managed_page() Matthew Wilcox (Oracle)
` (5 subsequent siblings)
6 siblings, 0 replies; 10+ messages in thread
From: Matthew Wilcox (Oracle) @ 2024-04-24 19:19 UTC (permalink / raw
To: Andrew Morton; +Cc: Matthew Wilcox (Oracle), linux-mm
All callers have now been converted to filemap_alloc_folio().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/pagemap.h | 5 -----
1 file changed, 5 deletions(-)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 941f7ed714b9..1dcaf86fb615 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -557,11 +557,6 @@ static inline struct page *__page_cache_alloc(gfp_t gfp)
return &filemap_alloc_folio(gfp, 0)->page;
}
-static inline struct page *page_cache_alloc(struct address_space *x)
-{
- return __page_cache_alloc(mapping_gfp_mask(x));
-}
-
static inline gfp_t readahead_gfp_mask(struct address_space *x)
{
return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
--
2.43.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 2/7] mm: Remove put_devmap_managed_page()
2024-04-24 19:19 [PATCH 0/7] More folio compat code removal Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 1/7] mm: Remove page_cache_alloc() Matthew Wilcox (Oracle)
@ 2024-04-24 19:19 ` Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 3/7] mm: Convert put_devmap_managed_page_refs() to put_devmap_managed_folio_refs() Matthew Wilcox (Oracle)
` (4 subsequent siblings)
6 siblings, 0 replies; 10+ messages in thread
From: Matthew Wilcox (Oracle) @ 2024-04-24 19:19 UTC (permalink / raw
To: Andrew Morton; +Cc: Matthew Wilcox (Oracle), linux-mm
It only has one caller; convert that caller to use
put_devmap_managed_page_refs() instead.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/mm.h | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e36db5e4509b..070a6e2d7222 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1453,11 +1453,6 @@ static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
}
#endif /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
-static inline bool put_devmap_managed_page(struct page *page)
-{
- return put_devmap_managed_page_refs(page, 1);
-}
-
/* 127: arbitrary random number, small enough to assemble well */
#define folio_ref_zero_or_close_to_overflow(folio) \
((unsigned int) folio_ref_count(folio) + 127u <= 127u)
@@ -1576,7 +1571,7 @@ static inline void put_page(struct page *page)
* For some devmap managed pages we need to catch refcount transition
* from 2 to 1:
*/
- if (put_devmap_managed_page(&folio->page))
+ if (put_devmap_managed_page_refs(&folio->page, 1))
return;
folio_put(folio);
}
--
2.43.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 3/7] mm: Convert put_devmap_managed_page_refs() to put_devmap_managed_folio_refs()
2024-04-24 19:19 [PATCH 0/7] More folio compat code removal Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 1/7] mm: Remove page_cache_alloc() Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 2/7] mm: Remove put_devmap_managed_page() Matthew Wilcox (Oracle)
@ 2024-04-24 19:19 ` Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 4/7] mm: Remove page_ref_sub_return() Matthew Wilcox (Oracle)
` (3 subsequent siblings)
6 siblings, 0 replies; 10+ messages in thread
From: Matthew Wilcox (Oracle) @ 2024-04-24 19:19 UTC (permalink / raw
To: Andrew Morton; +Cc: Matthew Wilcox (Oracle), linux-mm
All callers have a folio so we can remove this use of
page_ref_sub_return().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/mm.h | 12 ++++++------
mm/gup.c | 6 +++---
mm/memremap.c | 10 +++++-----
mm/swap.c | 2 +-
4 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 070a6e2d7222..19d0ec4f43f4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1437,17 +1437,17 @@ vm_fault_t finish_fault(struct vm_fault *vmf);
#if defined(CONFIG_ZONE_DEVICE) && defined(CONFIG_FS_DAX)
DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
-bool __put_devmap_managed_page_refs(struct page *page, int refs);
-static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
+bool __put_devmap_managed_folio_refs(struct folio *folio, int refs);
+static inline bool put_devmap_managed_folio_refs(struct folio *folio, int refs)
{
if (!static_branch_unlikely(&devmap_managed_key))
return false;
- if (!is_zone_device_page(page))
+ if (!folio_is_zone_device(folio))
return false;
- return __put_devmap_managed_page_refs(page, refs);
+ return __put_devmap_managed_folio_refs(folio, refs);
}
#else /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
-static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
+static inline bool put_devmap_managed_folio_refs(struct folio *folio, int refs)
{
return false;
}
@@ -1571,7 +1571,7 @@ static inline void put_page(struct page *page)
* For some devmap managed pages we need to catch refcount transition
* from 2 to 1:
*/
- if (put_devmap_managed_page_refs(&folio->page, 1))
+ if (put_devmap_managed_folio_refs(folio, 1))
return;
folio_put(folio);
}
diff --git a/mm/gup.c b/mm/gup.c
index b797424f78ef..49376f756936 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -89,7 +89,7 @@ static inline struct folio *try_get_folio(struct page *page, int refs)
* belongs to this folio.
*/
if (unlikely(page_folio(page) != folio)) {
- if (!put_devmap_managed_page_refs(&folio->page, refs))
+ if (!put_devmap_managed_folio_refs(folio, refs))
folio_put_refs(folio, refs);
goto retry;
}
@@ -156,7 +156,7 @@ struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags)
*/
if (unlikely((flags & FOLL_LONGTERM) &&
!folio_is_longterm_pinnable(folio))) {
- if (!put_devmap_managed_page_refs(&folio->page, refs))
+ if (!put_devmap_managed_folio_refs(folio, refs))
folio_put_refs(folio, refs);
return NULL;
}
@@ -198,7 +198,7 @@ static void gup_put_folio(struct folio *folio, int refs, unsigned int flags)
refs *= GUP_PIN_COUNTING_BIAS;
}
- if (!put_devmap_managed_page_refs(&folio->page, refs))
+ if (!put_devmap_managed_folio_refs(folio, refs))
folio_put_refs(folio, refs);
}
diff --git a/mm/memremap.c b/mm/memremap.c
index e1776693e2ea..40d4547ce514 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -512,9 +512,9 @@ void zone_device_page_init(struct page *page)
EXPORT_SYMBOL_GPL(zone_device_page_init);
#ifdef CONFIG_FS_DAX
-bool __put_devmap_managed_page_refs(struct page *page, int refs)
+bool __put_devmap_managed_folio_refs(struct folio *folio, int refs)
{
- if (page->pgmap->type != MEMORY_DEVICE_FS_DAX)
+ if (folio->page.pgmap->type != MEMORY_DEVICE_FS_DAX)
return false;
/*
@@ -522,9 +522,9 @@ bool __put_devmap_managed_page_refs(struct page *page, int refs)
* refcount is 1, then the page is free and the refcount is
* stable because nobody holds a reference on the page.
*/
- if (page_ref_sub_return(page, refs) == 1)
- wake_up_var(&page->_refcount);
+ if (folio_ref_sub_return(folio, refs) == 1)
+ wake_up_var(&folio->_refcount);
return true;
}
-EXPORT_SYMBOL(__put_devmap_managed_page_refs);
+EXPORT_SYMBOL(__put_devmap_managed_folio_refs);
#endif /* CONFIG_FS_DAX */
diff --git a/mm/swap.c b/mm/swap.c
index f0d478eee292..f29b3018ba3a 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -981,7 +981,7 @@ void folios_put_refs(struct folio_batch *folios, unsigned int *refs)
unlock_page_lruvec_irqrestore(lruvec, flags);
lruvec = NULL;
}
- if (put_devmap_managed_page_refs(&folio->page, nr_refs))
+ if (put_devmap_managed_folio_refs(folio, nr_refs))
continue;
if (folio_ref_sub_and_test(folio, nr_refs))
free_zone_device_folio(folio);
--
2.43.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 4/7] mm: Remove page_ref_sub_return()
2024-04-24 19:19 [PATCH 0/7] More folio compat code removal Matthew Wilcox (Oracle)
` (2 preceding siblings ...)
2024-04-24 19:19 ` [PATCH 3/7] mm: Convert put_devmap_managed_page_refs() to put_devmap_managed_folio_refs() Matthew Wilcox (Oracle)
@ 2024-04-24 19:19 ` Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 5/7] gup: Use folios for gup_devmap Matthew Wilcox (Oracle)
` (2 subsequent siblings)
6 siblings, 0 replies; 10+ messages in thread
From: Matthew Wilcox (Oracle) @ 2024-04-24 19:19 UTC (permalink / raw
To: Andrew Morton; +Cc: Matthew Wilcox (Oracle), linux-mm
With all callers converted to folios, we can act directly on
folio->_refcount.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/page_ref.h | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff --git a/include/linux/page_ref.h b/include/linux/page_ref.h
index d7c2d33baa7f..1acf5bac7f50 100644
--- a/include/linux/page_ref.h
+++ b/include/linux/page_ref.h
@@ -139,20 +139,15 @@ static inline void folio_ref_sub(struct folio *folio, int nr)
page_ref_sub(&folio->page, nr);
}
-static inline int page_ref_sub_return(struct page *page, int nr)
+static inline int folio_ref_sub_return(struct folio *folio, int nr)
{
- int ret = atomic_sub_return(nr, &page->_refcount);
+ int ret = atomic_sub_return(nr, &folio->_refcount);
if (page_ref_tracepoint_active(page_ref_mod_and_return))
- __page_ref_mod_and_return(page, -nr, ret);
+ __page_ref_mod_and_return(&folio->page, -nr, ret);
return ret;
}
-static inline int folio_ref_sub_return(struct folio *folio, int nr)
-{
- return page_ref_sub_return(&folio->page, nr);
-}
-
static inline void page_ref_inc(struct page *page)
{
atomic_inc(&page->_refcount);
--
2.43.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 5/7] gup: Use folios for gup_devmap
2024-04-24 19:19 [PATCH 0/7] More folio compat code removal Matthew Wilcox (Oracle)
` (3 preceding siblings ...)
2024-04-24 19:19 ` [PATCH 4/7] mm: Remove page_ref_sub_return() Matthew Wilcox (Oracle)
@ 2024-04-24 19:19 ` Matthew Wilcox (Oracle)
2024-04-25 9:49 ` David Hildenbrand
2024-04-24 19:19 ` [PATCH 6/7] mm: Add kernel-doc for folio_mark_accessed() Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 7/7] mm: Remove PageReferenced Matthew Wilcox (Oracle)
6 siblings, 1 reply; 10+ messages in thread
From: Matthew Wilcox (Oracle) @ 2024-04-24 19:19 UTC (permalink / raw
To: Andrew Morton; +Cc: Matthew Wilcox (Oracle), linux-mm
Use try_grab_folio() instead of try_grab_page() so we get the folio
back that we calculated, and then use folio_set_referenced() instead
of SetPageReferenced(). Correspondingly, use gup_put_folio() to
put any unneeded references.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
mm/gup.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 49376f756936..e4cc12b8e985 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2877,13 +2877,10 @@ static void __maybe_unused gup_fast_undo_dev_pagemap(int *nr, int nr_start,
unsigned int flags, struct page **pages)
{
while ((*nr) - nr_start) {
- struct page *page = pages[--(*nr)];
+ struct folio *folio = page_folio(pages[--(*nr)]);
- ClearPageReferenced(page);
- if (flags & FOLL_PIN)
- unpin_user_page(page);
- else
- put_page(page);
+ folio_clear_referenced(folio);
+ gup_put_folio(folio, 1, flags);
}
}
@@ -3024,6 +3021,7 @@ static int gup_fast_devmap_leaf(unsigned long pfn, unsigned long addr,
struct dev_pagemap *pgmap = NULL;
do {
+ struct folio *folio;
struct page *page = pfn_to_page(pfn);
pgmap = get_dev_pagemap(pfn, pgmap);
@@ -3037,12 +3035,13 @@ static int gup_fast_devmap_leaf(unsigned long pfn, unsigned long addr,
break;
}
- SetPageReferenced(page);
- pages[*nr] = page;
- if (unlikely(try_grab_page(page, flags))) {
+ folio = try_grab_folio(page, 1, flags);
+ if (!folio) {
gup_fast_undo_dev_pagemap(nr, nr_start, flags, pages);
break;
}
+ folio_set_referenced(folio);
+ pages[*nr] = page;
(*nr)++;
pfn++;
} while (addr += PAGE_SIZE, addr != end);
--
2.43.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 6/7] mm: Add kernel-doc for folio_mark_accessed()
2024-04-24 19:19 [PATCH 0/7] More folio compat code removal Matthew Wilcox (Oracle)
` (4 preceding siblings ...)
2024-04-24 19:19 ` [PATCH 5/7] gup: Use folios for gup_devmap Matthew Wilcox (Oracle)
@ 2024-04-24 19:19 ` Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 7/7] mm: Remove PageReferenced Matthew Wilcox (Oracle)
6 siblings, 0 replies; 10+ messages in thread
From: Matthew Wilcox (Oracle) @ 2024-04-24 19:19 UTC (permalink / raw
To: Andrew Morton; +Cc: Matthew Wilcox (Oracle), linux-mm
Convert the existing documentation to kernel-doc and remove
references to pages.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
mm/swap.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/mm/swap.c b/mm/swap.c
index f29b3018ba3a..73bebd3ca6b7 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -448,15 +448,18 @@ static void folio_inc_refs(struct folio *folio)
}
#endif /* CONFIG_LRU_GEN */
-/*
- * Mark a page as having seen activity.
+/**
+ * folio_mark_accessed - Mark a folio as having seen activity.
+ * @folio: The folio to mark.
+ *
+ * This function will perform one of the following transitions:
*
- * inactive,unreferenced -> inactive,referenced
- * inactive,referenced -> active,unreferenced
- * active,unreferenced -> active,referenced
+ * * inactive,unreferenced -> inactive,referenced
+ * * inactive,referenced -> active,unreferenced
+ * * active,unreferenced -> active,referenced
*
- * When a newly allocated page is not yet visible, so safe for non-atomic ops,
- * __SetPageReferenced(page) may be substituted for mark_page_accessed(page).
+ * When a newly allocated folio is not yet visible, so safe for non-atomic ops,
+ * __folio_set_referenced() may be substituted for folio_mark_accessed().
*/
void folio_mark_accessed(struct folio *folio)
{
--
2.43.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 7/7] mm: Remove PageReferenced
2024-04-24 19:19 [PATCH 0/7] More folio compat code removal Matthew Wilcox (Oracle)
` (5 preceding siblings ...)
2024-04-24 19:19 ` [PATCH 6/7] mm: Add kernel-doc for folio_mark_accessed() Matthew Wilcox (Oracle)
@ 2024-04-24 19:19 ` Matthew Wilcox (Oracle)
6 siblings, 0 replies; 10+ messages in thread
From: Matthew Wilcox (Oracle) @ 2024-04-24 19:19 UTC (permalink / raw
To: Andrew Morton; +Cc: Matthew Wilcox (Oracle), linux-mm
All callers now use folio_*_referenced() so we can remove the
PageReferenced family of functions.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/page-flags.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 5a5f84d75f31..c79f78d0ab72 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -508,9 +508,9 @@ static inline int TestClearPage##uname(struct page *page) { return 0; }
__PAGEFLAG(Locked, locked, PF_NO_TAIL)
FOLIO_FLAG(waiters, FOLIO_HEAD_PAGE)
-PAGEFLAG(Referenced, referenced, PF_HEAD)
- TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
- __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
+FOLIO_FLAG(referenced, FOLIO_HEAD_PAGE)
+ FOLIO_TEST_CLEAR_FLAG(referenced, FOLIO_HEAD_PAGE)
+ __FOLIO_SET_FLAG(referenced, FOLIO_HEAD_PAGE)
PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
__CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
--
2.43.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 5/7] gup: Use folios for gup_devmap
2024-04-24 19:19 ` [PATCH 5/7] gup: Use folios for gup_devmap Matthew Wilcox (Oracle)
@ 2024-04-25 9:49 ` David Hildenbrand
2024-04-25 12:43 ` Matthew Wilcox
0 siblings, 1 reply; 10+ messages in thread
From: David Hildenbrand @ 2024-04-25 9:49 UTC (permalink / raw
To: Matthew Wilcox (Oracle), Andrew Morton; +Cc: linux-mm
On 24.04.24 21:19, Matthew Wilcox (Oracle) wrote:
Nit: s/gup_devmap/gup_fast_devmap/
> Use try_grab_folio() instead of try_grab_page() so we get the folio
> back that we calculated, and then use folio_set_referenced() instead
> of SetPageReferenced(). Correspondingly, use gup_put_folio() to
> put any unneeded references.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
> mm/gup.c | 17 ++++++++---------
> 1 file changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index 49376f756936..e4cc12b8e985 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -2877,13 +2877,10 @@ static void __maybe_unused gup_fast_undo_dev_pagemap(int *nr, int nr_start,
> unsigned int flags, struct page **pages)
> {
> while ((*nr) - nr_start) {
> - struct page *page = pages[--(*nr)];
> + struct folio *folio = page_folio(pages[--(*nr)]);
>
> - ClearPageReferenced(page);
I stumbled over that likely unwarranted ClearPageReferenced() recently
as well: what if the page was already referenced before we called
SetPageReferenced?
> - if (flags & FOLL_PIN)
> - unpin_user_page(page);
> - else
> - put_page(page);
> + folio_clear_referenced(folio);
> + gup_put_folio(folio, 1, flags);
For !FOLL_PIN, we wouldn't have done the
if (!put_devmap_managed_page_refs(&folio->page, refs))
folio_put_refs(folio, refs);
Magic in gup_put_folio()
... was that a BUG?
This devmap crap is so confusing.
--
Cheers,
David / dhildenb
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 5/7] gup: Use folios for gup_devmap
2024-04-25 9:49 ` David Hildenbrand
@ 2024-04-25 12:43 ` Matthew Wilcox
0 siblings, 0 replies; 10+ messages in thread
From: Matthew Wilcox @ 2024-04-25 12:43 UTC (permalink / raw
To: David Hildenbrand; +Cc: Andrew Morton, linux-mm
On Thu, Apr 25, 2024 at 11:49:01AM +0200, David Hildenbrand wrote:
> > while ((*nr) - nr_start) {
> > - struct page *page = pages[--(*nr)];
> > + struct folio *folio = page_folio(pages[--(*nr)]);
> > - ClearPageReferenced(page);
>
> I stumbled over that likely unwarranted ClearPageReferenced() recently as
> well: what if the page was already referenced before we called
> SetPageReferenced?
Yes, it seems bizarre. I imagine the person who wrote this was trying
to undo everything, but no other cleanup path calls
folio_clear_referenced(). I don't object to taking it out.
> > - if (flags & FOLL_PIN)
> > - unpin_user_page(page);
> > - else
> > - put_page(page);
> > + folio_clear_referenced(folio);
> > + gup_put_folio(folio, 1, flags);
>
> For !FOLL_PIN, we wouldn't have done the
> if (!put_devmap_managed_page_refs(&folio->page, refs))
> folio_put_refs(folio, refs);
>
> Magic in gup_put_folio()
>
> ... was that a BUG?
I think so. But probably nobody noticed because it's an error path.
Also nobody noticed that we shouldn't have called SetPageReferenced()
before getting the refcount on the page. I didn't bother mentioning it
in the changelog because I think it's harmless, just conceptually wrong.
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2024-04-25 12:43 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
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2024-04-24 19:19 [PATCH 0/7] More folio compat code removal Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 1/7] mm: Remove page_cache_alloc() Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 2/7] mm: Remove put_devmap_managed_page() Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 3/7] mm: Convert put_devmap_managed_page_refs() to put_devmap_managed_folio_refs() Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 4/7] mm: Remove page_ref_sub_return() Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 5/7] gup: Use folios for gup_devmap Matthew Wilcox (Oracle)
2024-04-25 9:49 ` David Hildenbrand
2024-04-25 12:43 ` Matthew Wilcox
2024-04-24 19:19 ` [PATCH 6/7] mm: Add kernel-doc for folio_mark_accessed() Matthew Wilcox (Oracle)
2024-04-24 19:19 ` [PATCH 7/7] mm: Remove PageReferenced Matthew Wilcox (Oracle)
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