From: Matthew Wilcox <willy@infradead.org>
To: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v4 07/25] mm: Create FolioFlags
Date: Mon, 15 Mar 2021 02:24:32 +0000 [thread overview]
Message-ID: <20210315022432.GS2577561@casper.infradead.org> (raw)
In-Reply-To: <20210305041901.2396498-8-willy@infradead.org>
On Fri, Mar 05, 2021 at 04:18:43AM +0000, Matthew Wilcox (Oracle) wrote:
> These new functions are the folio analogues of the PageFlags functions.
> If CONFIG_DEBUG_VM_PGFLAGS is enabled, we check the folio is not a tail
> page at every invocation. Note that this will also catch the PagePoisoned
> case as a poisoned page has every bit set, which would include PageTail.
>
> This saves 1740 bytes of text with the distro-derived config that
> I'm testing due to removing a double call to compound_head() in
> PageSwapCache().
This patch is buggy due to using the wrong page->flags for FolioDoubleMapped.
I'm not totally in love with this fix, but it does work without changing
every PAGEFLAG definition.
(also, I needed FolioTransHuge())
commit fe8ca904171345d113f06f381c255a3c4b20074e
Author: Matthew Wilcox (Oracle) <willy@infradead.org>
Date: Sun Mar 14 17:34:48 2021 -0400
fix FolioFlags
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 01aa4a71bf14..b7fd4c3733ca 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -212,10 +212,13 @@ static inline void page_init_poison(struct page *page, size_t size)
}
#endif
-static unsigned long *folio_flags(struct folio *folio)
+static unsigned long *folio_flags(struct folio *folio, unsigned n)
{
- VM_BUG_ON_PGFLAGS(PageTail(&folio->page), &folio->page);
- return &folio->page.flags;
+ struct page *page = &folio->page;
+
+ VM_BUG_ON_PGFLAGS(PageTail(page), page);
+ VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page);
+ return &page[n].flags;
}
/*
@@ -262,48 +265,56 @@ static unsigned long *folio_flags(struct folio *folio)
VM_BUG_ON_PGFLAGS(!PageHead(page), page); \
PF_POISONED_CHECK(&page[1]); })
+/* Which page is the flag stored in */
+#define FOLIO_PF_ANY 0
+#define FOLIO_PF_HEAD 0
+#define FOLIO_PF_ONLY_HEAD 0
+#define FOLIO_PF_NO_TAIL 0
+#define FOLIO_PF_NO_COMPOUND 0
+#define FOLIO_PF_SECOND 1
+
/*
* Macros to create function definitions for page flags
*/
#define TESTPAGEFLAG(uname, lname, policy) \
static __always_inline int Folio##uname(struct folio *folio) \
- { return test_bit(PG_##lname, folio_flags(folio)); } \
+ { return test_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline int Page##uname(struct page *page) \
{ return test_bit(PG_##lname, &policy(page, 0)->flags); }
#define SETPAGEFLAG(uname, lname, policy) \
static __always_inline void SetFolio##uname(struct folio *folio) \
- { set_bit(PG_##lname, folio_flags(folio)); } \
+ { set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline void SetPage##uname(struct page *page) \
{ set_bit(PG_##lname, &policy(page, 1)->flags); }
#define CLEARPAGEFLAG(uname, lname, policy) \
static __always_inline void ClearFolio##uname(struct folio *folio) \
- { clear_bit(PG_##lname, folio_flags(folio)); } \
+ { clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline void ClearPage##uname(struct page *page) \
{ clear_bit(PG_##lname, &policy(page, 1)->flags); }
#define __SETPAGEFLAG(uname, lname, policy) \
static __always_inline void __SetFolio##uname(struct folio *folio) \
- { __set_bit(PG_##lname, folio_flags(folio)); } \
+ { __set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline void __SetPage##uname(struct page *page) \
{ __set_bit(PG_##lname, &policy(page, 1)->flags); }
#define __CLEARPAGEFLAG(uname, lname, policy) \
static __always_inline void __ClearFolio##uname(struct folio *folio) \
- { __clear_bit(PG_##lname, folio_flags(folio)); } \
+ { __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline void __ClearPage##uname(struct page *page) \
{ __clear_bit(PG_##lname, &policy(page, 1)->flags); }
#define TESTSETFLAG(uname, lname, policy) \
static __always_inline int TestSetFolio##uname(struct folio *folio) \
- { return test_and_set_bit(PG_##lname, folio_flags(folio)); } \
+ { return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline int TestSetPage##uname(struct page *page) \
{ return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
#define TESTCLEARFLAG(uname, lname, policy) \
static __always_inline int TestClearFolio##uname(struct folio *folio) \
- { return test_and_clear_bit(PG_##lname, folio_flags(folio)); } \
+ { return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline int TestClearPage##uname(struct page *page) \
{ return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
@@ -422,7 +433,7 @@ PAGEFLAG_FALSE(HighMem)
static __always_inline bool FolioSwapCache(struct folio *folio)
{
return FolioSwapBacked(folio) &&
- test_bit(PG_swapcache, folio_flags(folio));
+ test_bit(PG_swapcache, folio_flags(folio, 0));
}
@@ -545,7 +556,7 @@ u64 stable_page_flags(struct page *page);
static inline int FolioUptodate(struct folio *folio)
{
- int ret = test_bit(PG_uptodate, folio_flags(folio));
+ int ret = test_bit(PG_uptodate, folio_flags(folio, 0));
/*
* Must ensure that the data we read out of the page is loaded
* _after_ we've loaded page->flags to check for PageUptodate.
@@ -568,7 +579,7 @@ static inline int PageUptodate(struct page *page)
static __always_inline void __SetFolioUptodate(struct folio *folio)
{
smp_wmb();
- __set_bit(PG_uptodate, folio_flags(folio));
+ __set_bit(PG_uptodate, folio_flags(folio, 0));
}
static __always_inline void SetFolioUptodate(struct folio *folio)
@@ -579,7 +590,7 @@ static __always_inline void SetFolioUptodate(struct folio *folio)
* uptodate are actually visible before PageUptodate becomes true.
*/
smp_wmb();
- set_bit(PG_uptodate, folio_flags(folio));
+ set_bit(PG_uptodate, folio_flags(folio, 0));
}
static __always_inline void __SetPageUptodate(struct page *page)
@@ -672,6 +683,11 @@ static inline int PageTransHuge(struct page *page)
return PageHead(page);
}
+static inline bool FolioTransHuge(struct folio *folio)
+{
+ return FolioHead(folio);
+}
+
/*
* PageTransCompound returns true for both transparent huge pages
* and hugetlbfs pages, so it should only be called when it's known
next prev parent reply other threads:[~2021-03-15 2:24 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-05 4:18 [PATCH v4 00/25] Page folios Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 01/25] mm: Introduce struct folio Matthew Wilcox (Oracle)
2021-03-13 20:37 ` Andrew Morton
2021-03-14 4:07 ` Matthew Wilcox
2021-03-17 17:14 ` Christoph Hellwig
2021-03-18 23:56 ` Balbir Singh
2021-03-19 1:25 ` Matthew Wilcox
2021-03-20 2:09 ` Balbir Singh
2021-03-22 2:52 ` Nicholas Piggin
2021-03-22 3:54 ` Matthew Wilcox
2021-03-05 4:18 ` [PATCH v4 02/25] mm: Add folio_pgdat and folio_zone Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 03/25] mm/vmstat: Add functions to account folio statistics Matthew Wilcox (Oracle)
2021-03-13 20:37 ` Andrew Morton
2021-03-14 4:11 ` Matthew Wilcox
2021-03-14 4:51 ` Andrew Morton
2021-03-17 17:16 ` Christoph Hellwig
2021-03-05 4:18 ` [PATCH v4 04/25] mm/debug: Add VM_BUG_ON_FOLIO and VM_WARN_ON_ONCE_FOLIO Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 05/25] mm: Add put_folio Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 06/25] mm: Add get_folio Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 07/25] mm: Create FolioFlags Matthew Wilcox (Oracle)
2021-03-15 2:24 ` Matthew Wilcox [this message]
2021-03-05 4:18 ` [PATCH v4 08/25] mm: Handle per-folio private data Matthew Wilcox (Oracle)
2021-03-17 17:20 ` Christoph Hellwig
2021-03-18 17:57 ` Matthew Wilcox
2021-03-05 4:18 ` [PATCH v4 09/25] mm: Add folio_index, folio_page and folio_contains Matthew Wilcox (Oracle)
2021-03-13 20:37 ` Andrew Morton
2021-03-14 3:45 ` Matthew Wilcox
2021-03-17 17:22 ` Christoph Hellwig
2021-03-05 4:18 ` [PATCH v4 10/25] mm/util: Add folio_mapping and folio_file_mapping Matthew Wilcox (Oracle)
2021-03-17 17:26 ` Christoph Hellwig
2021-03-05 4:18 ` [PATCH v4 11/25] mm/memcg: Add folio wrappers for various memcontrol functions Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 12/25] mm/filemap: Add unlock_folio Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 13/25] mm/filemap: Add lock_folio Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 14/25] mm/filemap: Add lock_folio_killable Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 15/25] mm/filemap: Convert lock_page_async to lock_folio_async Matthew Wilcox (Oracle)
2021-03-17 17:29 ` Christoph Hellwig
2021-03-05 4:18 ` [PATCH v4 16/25] mm/filemap: Convert end_page_writeback to end_folio_writeback Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 17/25] mm/filemap: Add wait_on_folio_locked & wait_on_folio_locked_killable Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 18/25] mm/page-writeback: Add wait_on_folio_writeback Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 19/25] mm/page-writeback: Add wait_for_stable_folio Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 20/25] mm/filemap: Convert wait_on_page_bit to wait_on_folio_bit Matthew Wilcox (Oracle)
2021-03-17 17:39 ` Christoph Hellwig
2021-03-05 4:18 ` [PATCH v4 21/25] mm/filemap: Add __lock_folio_or_retry Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 22/25] mm/filemap: Convert wake_up_page_bit to wake_up_folio_bit Matthew Wilcox (Oracle)
2021-03-05 4:18 ` [PATCH v4 23/25] mm/page-writeback: Convert test_clear_page_writeback to take a folio Matthew Wilcox (Oracle)
2021-03-05 4:19 ` [PATCH v4 24/25] mm/filemap: Convert page wait queues to be folios Matthew Wilcox (Oracle)
2021-03-05 4:19 ` [PATCH v4 25/25] cachefiles: Switch to wait_page_key Matthew Wilcox (Oracle)
2021-03-17 17:45 ` Christoph Hellwig
2021-03-13 20:36 ` [PATCH v4 00/25] Page folios Andrew Morton
2021-03-14 2:30 ` Matthew Wilcox
2021-03-14 3:09 ` Hugh Dickins
[not found] ` <20210315115501.7rmzaan2hxsqowgq@box>
2021-03-15 13:45 ` Matthew Wilcox
[not found] ` <YE9VLGl50hLIJHci@dhcp22.suse.cz>
2021-03-15 19:09 ` Christoph Hellwig
2021-03-15 19:40 ` Matthew Wilcox
2021-03-15 22:27 ` Dave Chinner
2021-03-17 17:48 ` Christoph Hellwig
2021-03-15 21:33 ` Andi Kleen
2021-03-19 4:01 ` Matthew Wilcox
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