Export all page flags faithfully in /proc/kpageflags. 11. KPF_MMAP (pseudo flag) memory mapped page 12. KPF_ANON (pseudo flag) memory mapped page (anonymous) 13. KPF_SWAPCACHE page is in swap cache 14. KPF_SWAPBACKED page is swap/RAM backed 15. KPF_COMPOUND_HEAD (*) 16. KPF_COMPOUND_TAIL (*) 17. KPF_HUGE hugeTLB pages 18. KPF_UNEVICTABLE page is in the unevictable LRU list 19. KPF_HWPOISON(TBD) hardware detected corruption 20. KPF_NOPAGE (pseudo flag) no page frame at the address 32-39. more obscure flags for kernel developers (*) For compound pages, exporting _both_ head/tail info enables users to tell where a compound page starts/ends, and its order. The acompanied page-types tool will handle the details like decoupling overloaded flags and hiding obscure flags to normal users. Thanks to KOSAKI and Andi for their valuable recommendations! Cc: KOSAKI Motohiro Cc: Andi Kleen Cc: Matt Mackall Cc: Alexey Dobriyan Signed-off-by: Wu Fengguang --- fs/proc/page.c | 148 +++++++++++++++++++++++++++++++++++++---------- 1 file changed, 118 insertions(+), 30 deletions(-) --- linux.orig/fs/proc/page.c +++ linux/fs/proc/page.c @@ -71,19 +71,124 @@ static const struct file_operations proc /* These macros are used to decouple internal flags from exported ones */ -#define KPF_LOCKED 0 -#define KPF_ERROR 1 -#define KPF_REFERENCED 2 -#define KPF_UPTODATE 3 -#define KPF_DIRTY 4 -#define KPF_LRU 5 -#define KPF_ACTIVE 6 -#define KPF_SLAB 7 -#define KPF_WRITEBACK 8 -#define KPF_RECLAIM 9 -#define KPF_BUDDY 10 +#define KPF_LOCKED 0 +#define KPF_ERROR 1 +#define KPF_REFERENCED 2 +#define KPF_UPTODATE 3 +#define KPF_DIRTY 4 +#define KPF_LRU 5 +#define KPF_ACTIVE 6 +#define KPF_SLAB 7 +#define KPF_WRITEBACK 8 +#define KPF_RECLAIM 9 +#define KPF_BUDDY 10 + +/* 11-20: new additions in 2.6.31 */ +#define KPF_MMAP 11 +#define KPF_ANON 12 +#define KPF_SWAPCACHE 13 +#define KPF_SWAPBACKED 14 +#define KPF_COMPOUND_HEAD 15 +#define KPF_COMPOUND_TAIL 16 +#define KPF_HUGE 17 +#define KPF_UNEVICTABLE 18 +#define KPF_NOPAGE 20 + +/* kernel hacking assistances + * WARNING: subject to change, never rely on them! + */ +#define KPF_RESERVED 32 +#define KPF_MLOCKED 33 +#define KPF_MAPPEDTODISK 34 +#define KPF_PRIVATE 35 +#define KPF_PRIVATE_2 36 +#define KPF_OWNER_PRIVATE 37 +#define KPF_ARCH 38 +#define KPF_UNCACHED 39 -#define kpf_copy_bit(flags, dstpos, srcpos) (((flags >> srcpos) & 1) << dstpos) +static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit) +{ + return ((kflags >> kbit) & 1) << ubit; +} + +static u64 get_uflags(struct page *page) +{ + u64 k; + u64 u; + + /* + * pseudo flag: KPF_NOPAGE + * it differentiates a memory hole from a page with no flags + */ + if (!page) + return 1 << KPF_NOPAGE; + + k = page->flags; + u = 0; + + /* + * pseudo flags for the well known (anonymous) memory mapped pages + * + * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the + * simple test in page_mapped() is not enough. + */ + if (!PageSlab(page) && page_mapped(page)) + u |= 1 << KPF_MMAP; + if (PageAnon(page)) + u |= 1 << KPF_ANON; + + /* + * compound pages: export both head/tail info + * they together define a compound page's start/end pos and order + */ + if (PageHead(page)) + u |= 1 << KPF_COMPOUND_HEAD; + if (PageTail(page)) + u |= 1 << KPF_COMPOUND_TAIL; + if (PageHuge(page)) + u |= 1 << KPF_HUGE; + + u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked); + + /* + * Caveats on high order pages: + * PG_buddy will only be set on the head page; SLUB/SLQB do the same + * for PG_slab; SLOB won't set PG_slab at all on compound pages. + */ + u |= kpf_copy_bit(k, KPF_SLAB, PG_slab); + u |= kpf_copy_bit(k, KPF_BUDDY, PG_buddy); + + u |= kpf_copy_bit(k, KPF_ERROR, PG_error); + u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty); + u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate); + u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback); + + u |= kpf_copy_bit(k, KPF_LRU, PG_lru); + u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced); + u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active); + u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim); + + u |= kpf_copy_bit(k, KPF_SWAPCACHE, PG_swapcache); + u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked); + +#ifdef CONFIG_UNEVICTABLE_LRU + u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable); + u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); +#endif + +#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR + u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached); +#endif + + u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved); + u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk); + u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private); + u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2); + u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1); + u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1); + + return u; +}; static ssize_t kpageflags_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) @@ -93,7 +198,6 @@ static ssize_t kpageflags_read(struct fi unsigned long src = *ppos; unsigned long pfn; ssize_t ret = 0; - u64 kflags, uflags; pfn = src / KPMSIZE; count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src); @@ -105,24 +209,8 @@ static ssize_t kpageflags_read(struct fi ppage = pfn_to_page(pfn); else ppage = NULL; - if (!ppage) - kflags = 0; - else - kflags = ppage->flags; - - uflags = kpf_copy_bit(kflags, KPF_LOCKED, PG_locked) | - kpf_copy_bit(kflags, KPF_ERROR, PG_error) | - kpf_copy_bit(kflags, KPF_REFERENCED, PG_referenced) | - kpf_copy_bit(kflags, KPF_UPTODATE, PG_uptodate) | - kpf_copy_bit(kflags, KPF_DIRTY, PG_dirty) | - kpf_copy_bit(kflags, KPF_LRU, PG_lru) | - kpf_copy_bit(kflags, KPF_ACTIVE, PG_active) | - kpf_copy_bit(kflags, KPF_SLAB, PG_slab) | - kpf_copy_bit(kflags, KPF_WRITEBACK, PG_writeback) | - kpf_copy_bit(kflags, KPF_RECLAIM, PG_reclaim) | - kpf_copy_bit(kflags, KPF_BUDDY, PG_buddy); - if (put_user(uflags, out)) { + if (put_user(get_uflags(ppage), out)) { ret = -EFAULT; break; } -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/