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[PATCH] unpaged: unifdefed PageCompound 

It looks like snd_xxx is not the only nopage to be using PageReserved as a way
of holding a high-order page together: which no longer works, but is masked by
our failure to free from VM_RESERVED areas.  We cannot fix that bug without
first substituting another way to hold the high-order page together, while
farming out the 0-order pages from within it.

That's just what PageCompound is designed for, but it's been kept under
CONFIG_HUGETLB_PAGE.  Remove the #ifdefs: which saves some space (out- of-line
put_page), doesn't slow down what most needs to be fast (already using
hugetlb), and unifies the way we handle high-order pages.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Hugh Dickins 2005-11-21 21:32:14 -08:00 committed by Linus Torvalds
parent 1cdca61bf8
commit 664beed019
4 changed files with 0 additions and 31 deletions
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19
include/linux/mm.h
View File

@ -311,8 +311,6 @@ struct page {
extern void FASTCALL(__page_cache_release(struct page *));
#ifdef CONFIG_HUGETLB_PAGE
static inline int page_count(struct page *page)
{
if (PageCompound(page))
@ -329,23 +327,6 @@ static inline void get_page(struct page *page)
void put_page(struct page *page);
#else /* CONFIG_HUGETLB_PAGE */
#define page_count(p) (atomic_read(&(p)->_count) + 1)
static inline void get_page(struct page *page)
{
atomic_inc(&page->_count);
}
static inline void put_page(struct page *page)
{
if (put_page_testzero(page))
__page_cache_release(page);
}
#endif /* CONFIG_HUGETLB_PAGE */
/*
* Multiple processes may "see" the same page. E.g. for untouched
* mappings of /dev/null, all processes see the same page full of

4
include/linux/page-flags.h
View File

@ -287,11 +287,7 @@ extern void __mod_page_state(unsigned long offset, unsigned long delta);
#define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags)
#define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)
#ifdef CONFIG_HUGETLB_PAGE
#define PageCompound(page) test_bit(PG_compound, &(page)->flags)
#else
#define PageCompound(page) 0
#endif
#define SetPageCompound(page) set_bit(PG_compound, &(page)->flags)
#define ClearPageCompound(page) clear_bit(PG_compound, &(page)->flags)

5
mm/page_alloc.c
View File

@ -148,10 +148,6 @@ static void bad_page(const char *function, struct page *page)
add_taint(TAINT_BAD_PAGE);
}
#ifndef CONFIG_HUGETLB_PAGE
#define prep_compound_page(page, order) do { } while (0)
#define destroy_compound_page(page, order) do { } while (0)
#else
/*
* Higher-order pages are called "compound pages". They are structured thusly:
*
@ -205,7 +201,6 @@ static void destroy_compound_page(struct page *page, unsigned long order)
ClearPageCompound(p);
}
}
#endif /* CONFIG_HUGETLB_PAGE */
/*
* function for dealing with page's order in buddy system.

3
mm/swap.c
View File

@ -34,8 +34,6 @@
/* How many pages do we try to swap or page in/out together? */
int page_cluster;
#ifdef CONFIG_HUGETLB_PAGE
void put_page(struct page *page)
{
if (unlikely(PageCompound(page))) {
@ -52,7 +50,6 @@ void put_page(struct page *page)
__page_cache_release(page);
}
EXPORT_SYMBOL(put_page);
#endif
/*
* Writeback is about to end against a page which has been marked for immediate