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-rw-r--r--include/linux/page-flags.h324
1 files changed, 324 insertions, 0 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
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--- /dev/null
+++ b/include/linux/page-flags.h
@@ -0,0 +1,324 @@
+/*
+ * Macros for manipulating and testing page->flags
+ */
+
+#ifndef PAGE_FLAGS_H
+#define PAGE_FLAGS_H
+
+#include <linux/percpu.h>
+#include <linux/cache.h>
+#include <asm/pgtable.h>
+
+/*
+ * Various page->flags bits:
+ *
+ * PG_reserved is set for special pages, which can never be swapped out. Some
+ * of them might not even exist (eg empty_bad_page)...
+ *
+ * The PG_private bitflag is set if page->private contains a valid value.
+ *
+ * During disk I/O, PG_locked is used. This bit is set before I/O and
+ * reset when I/O completes. page_waitqueue(page) is a wait queue of all tasks
+ * waiting for the I/O on this page to complete.
+ *
+ * PG_uptodate tells whether the page's contents is valid. When a read
+ * completes, the page becomes uptodate, unless a disk I/O error happened.
+ *
+ * For choosing which pages to swap out, inode pages carry a PG_referenced bit,
+ * which is set any time the system accesses that page through the (mapping,
+ * index) hash table. This referenced bit, together with the referenced bit
+ * in the page tables, is used to manipulate page->age and move the page across
+ * the active, inactive_dirty and inactive_clean lists.
+ *
+ * Note that the referenced bit, the page->lru list_head and the active,
+ * inactive_dirty and inactive_clean lists are protected by the
+ * zone->lru_lock, and *NOT* by the usual PG_locked bit!
+ *
+ * PG_error is set to indicate that an I/O error occurred on this page.
+ *
+ * PG_arch_1 is an architecture specific page state bit. The generic code
+ * guarantees that this bit is cleared for a page when it first is entered into
+ * the page cache.
+ *
+ * PG_highmem pages are not permanently mapped into the kernel virtual address
+ * space, they need to be kmapped separately for doing IO on the pages. The
+ * struct page (these bits with information) are always mapped into kernel
+ * address space...
+ */
+
+/*
+ * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
+ * locked- and dirty-page accounting. The top eight bits of page->flags are
+ * used for page->zone, so putting flag bits there doesn't work.
+ */
+#define PG_locked 0 /* Page is locked. Don't touch. */
+#define PG_error 1
+#define PG_referenced 2
+#define PG_uptodate 3
+
+#define PG_dirty 4
+#define PG_lru 5
+#define PG_active 6
+#define PG_slab 7 /* slab debug (Suparna wants this) */
+
+#define PG_highmem 8
+#define PG_checked 9 /* kill me in 2.5.<early>. */
+#define PG_arch_1 10
+#define PG_reserved 11
+
+#define PG_private 12 /* Has something at ->private */
+#define PG_writeback 13 /* Page is under writeback */
+#define PG_nosave 14 /* Used for system suspend/resume */
+#define PG_compound 15 /* Part of a compound page */
+
+#define PG_swapcache 16 /* Swap page: swp_entry_t in private */
+#define PG_mappedtodisk 17 /* Has blocks allocated on-disk */
+#define PG_reclaim 18 /* To be reclaimed asap */
+#define PG_nosave_free 19 /* Free, should not be written */
+#define PG_uncached 20 /* Page has been mapped as uncached */
+
+/*
+ * Global page accounting. One instance per CPU. Only unsigned longs are
+ * allowed.
+ */
+struct page_state {
+ unsigned long nr_dirty; /* Dirty writeable pages */
+ unsigned long nr_writeback; /* Pages under writeback */
+ unsigned long nr_unstable; /* NFS unstable pages */
+ unsigned long nr_page_table_pages;/* Pages used for pagetables */
+ unsigned long nr_mapped; /* mapped into pagetables */
+ unsigned long nr_slab; /* In slab */
+#define GET_PAGE_STATE_LAST nr_slab
+
+ /*
+ * The below are zeroed by get_page_state(). Use get_full_page_state()
+ * to add up all these.
+ */
+ unsigned long pgpgin; /* Disk reads */
+ unsigned long pgpgout; /* Disk writes */
+ unsigned long pswpin; /* swap reads */
+ unsigned long pswpout; /* swap writes */
+ unsigned long pgalloc_high; /* page allocations */
+
+ unsigned long pgalloc_normal;
+ unsigned long pgalloc_dma;
+ unsigned long pgfree; /* page freeings */
+ unsigned long pgactivate; /* pages moved inactive->active */
+ unsigned long pgdeactivate; /* pages moved active->inactive */
+
+ unsigned long pgfault; /* faults (major+minor) */
+ unsigned long pgmajfault; /* faults (major only) */
+ unsigned long pgrefill_high; /* inspected in refill_inactive_zone */
+ unsigned long pgrefill_normal;
+ unsigned long pgrefill_dma;
+
+ unsigned long pgsteal_high; /* total highmem pages reclaimed */
+ unsigned long pgsteal_normal;
+ unsigned long pgsteal_dma;
+ unsigned long pgscan_kswapd_high;/* total highmem pages scanned */
+ unsigned long pgscan_kswapd_normal;
+
+ unsigned long pgscan_kswapd_dma;
+ unsigned long pgscan_direct_high;/* total highmem pages scanned */
+ unsigned long pgscan_direct_normal;
+ unsigned long pgscan_direct_dma;
+ unsigned long pginodesteal; /* pages reclaimed via inode freeing */
+
+ unsigned long slabs_scanned; /* slab objects scanned */
+ unsigned long kswapd_steal; /* pages reclaimed by kswapd */
+ unsigned long kswapd_inodesteal;/* reclaimed via kswapd inode freeing */
+ unsigned long pageoutrun; /* kswapd's calls to page reclaim */
+ unsigned long allocstall; /* direct reclaim calls */
+
+ unsigned long pgrotated; /* pages rotated to tail of the LRU */
+};
+
+extern void get_page_state(struct page_state *ret);
+extern void get_full_page_state(struct page_state *ret);
+extern unsigned long __read_page_state(unsigned offset);
+extern void __mod_page_state(unsigned offset, unsigned long delta);
+
+#define read_page_state(member) \
+ __read_page_state(offsetof(struct page_state, member))
+
+#define mod_page_state(member, delta) \
+ __mod_page_state(offsetof(struct page_state, member), (delta))
+
+#define inc_page_state(member) mod_page_state(member, 1UL)
+#define dec_page_state(member) mod_page_state(member, 0UL - 1)
+#define add_page_state(member,delta) mod_page_state(member, (delta))
+#define sub_page_state(member,delta) mod_page_state(member, 0UL - (delta))
+
+#define mod_page_state_zone(zone, member, delta) \
+ do { \
+ unsigned offset; \
+ if (is_highmem(zone)) \
+ offset = offsetof(struct page_state, member##_high); \
+ else if (is_normal(zone)) \
+ offset = offsetof(struct page_state, member##_normal); \
+ else \
+ offset = offsetof(struct page_state, member##_dma); \
+ __mod_page_state(offset, (delta)); \
+ } while (0)
+
+/*
+ * Manipulation of page state flags
+ */
+#define PageLocked(page) \
+ test_bit(PG_locked, &(page)->flags)
+#define SetPageLocked(page) \
+ set_bit(PG_locked, &(page)->flags)
+#define TestSetPageLocked(page) \
+ test_and_set_bit(PG_locked, &(page)->flags)
+#define ClearPageLocked(page) \
+ clear_bit(PG_locked, &(page)->flags)
+#define TestClearPageLocked(page) \
+ test_and_clear_bit(PG_locked, &(page)->flags)
+
+#define PageError(page) test_bit(PG_error, &(page)->flags)
+#define SetPageError(page) set_bit(PG_error, &(page)->flags)
+#define ClearPageError(page) clear_bit(PG_error, &(page)->flags)
+
+#define PageReferenced(page) test_bit(PG_referenced, &(page)->flags)
+#define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags)
+#define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags)
+#define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags)
+
+#define PageUptodate(page) test_bit(PG_uptodate, &(page)->flags)
+#ifndef SetPageUptodate
+#define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags)
+#endif
+#define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags)
+
+#define PageDirty(page) test_bit(PG_dirty, &(page)->flags)
+#define SetPageDirty(page) set_bit(PG_dirty, &(page)->flags)
+#define TestSetPageDirty(page) test_and_set_bit(PG_dirty, &(page)->flags)
+#define ClearPageDirty(page) clear_bit(PG_dirty, &(page)->flags)
+#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)
+
+#define SetPageLRU(page) set_bit(PG_lru, &(page)->flags)
+#define PageLRU(page) test_bit(PG_lru, &(page)->flags)
+#define TestSetPageLRU(page) test_and_set_bit(PG_lru, &(page)->flags)
+#define TestClearPageLRU(page) test_and_clear_bit(PG_lru, &(page)->flags)
+
+#define PageActive(page) test_bit(PG_active, &(page)->flags)
+#define SetPageActive(page) set_bit(PG_active, &(page)->flags)
+#define ClearPageActive(page) clear_bit(PG_active, &(page)->flags)
+#define TestClearPageActive(page) test_and_clear_bit(PG_active, &(page)->flags)
+#define TestSetPageActive(page) test_and_set_bit(PG_active, &(page)->flags)
+
+#define PageSlab(page) test_bit(PG_slab, &(page)->flags)
+#define SetPageSlab(page) set_bit(PG_slab, &(page)->flags)
+#define ClearPageSlab(page) clear_bit(PG_slab, &(page)->flags)
+#define TestClearPageSlab(page) test_and_clear_bit(PG_slab, &(page)->flags)
+#define TestSetPageSlab(page) test_and_set_bit(PG_slab, &(page)->flags)
+
+#ifdef CONFIG_HIGHMEM
+#define PageHighMem(page) test_bit(PG_highmem, &(page)->flags)
+#else
+#define PageHighMem(page) 0 /* needed to optimize away at compile time */
+#endif
+
+#define PageChecked(page) test_bit(PG_checked, &(page)->flags)
+#define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
+#define ClearPageChecked(page) clear_bit(PG_checked, &(page)->flags)
+
+#define PageReserved(page) test_bit(PG_reserved, &(page)->flags)
+#define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags)
+#define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags)
+#define __ClearPageReserved(page) __clear_bit(PG_reserved, &(page)->flags)
+
+#define SetPagePrivate(page) set_bit(PG_private, &(page)->flags)
+#define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags)
+#define PagePrivate(page) test_bit(PG_private, &(page)->flags)
+#define __SetPagePrivate(page) __set_bit(PG_private, &(page)->flags)
+#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
+
+#define PageWriteback(page) test_bit(PG_writeback, &(page)->flags)
+#define SetPageWriteback(page) \
+ do { \
+ if (!test_and_set_bit(PG_writeback, \
+ &(page)->flags)) \
+ inc_page_state(nr_writeback); \
+ } while (0)
+#define TestSetPageWriteback(page) \
+ ({ \
+ int ret; \
+ ret = test_and_set_bit(PG_writeback, \
+ &(page)->flags); \
+ if (!ret) \
+ inc_page_state(nr_writeback); \
+ ret; \
+ })
+#define ClearPageWriteback(page) \
+ do { \
+ if (test_and_clear_bit(PG_writeback, \
+ &(page)->flags)) \
+ dec_page_state(nr_writeback); \
+ } while (0)
+#define TestClearPageWriteback(page) \
+ ({ \
+ int ret; \
+ ret = test_and_clear_bit(PG_writeback, \
+ &(page)->flags); \
+ if (ret) \
+ dec_page_state(nr_writeback); \
+ ret; \
+ })
+
+#define PageNosave(page) test_bit(PG_nosave, &(page)->flags)
+#define SetPageNosave(page) set_bit(PG_nosave, &(page)->flags)
+#define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags)
+#define ClearPageNosave(page) clear_bit(PG_nosave, &(page)->flags)
+#define TestClearPageNosave(page) test_and_clear_bit(PG_nosave, &(page)->flags)
+
+#define PageNosaveFree(page) test_bit(PG_nosave_free, &(page)->flags)
+#define SetPageNosaveFree(page) set_bit(PG_nosave_free, &(page)->flags)
+#define ClearPageNosaveFree(page) clear_bit(PG_nosave_free, &(page)->flags)
+
+#define PageMappedToDisk(page) test_bit(PG_mappedtodisk, &(page)->flags)
+#define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
+#define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)
+
+#define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags)
+#define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags)
+#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)
+
+#ifdef CONFIG_SWAP
+#define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags)
+#define SetPageSwapCache(page) set_bit(PG_swapcache, &(page)->flags)
+#define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags)
+#else
+#define PageSwapCache(page) 0
+#endif
+
+#define PageUncached(page) test_bit(PG_uncached, &(page)->flags)
+#define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags)
+#define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags)
+
+struct page; /* forward declaration */
+
+int test_clear_page_dirty(struct page *page);
+int test_clear_page_writeback(struct page *page);
+int test_set_page_writeback(struct page *page);
+
+static inline void clear_page_dirty(struct page *page)
+{
+ test_clear_page_dirty(page);
+}
+
+static inline void set_page_writeback(struct page *page)
+{
+ test_set_page_writeback(page);
+}
+
+#endif /* PAGE_FLAGS_H */