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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/linux/swapops.h | |
download | linux-stable-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz linux-stable-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 linux-stable-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/linux/swapops.h')
-rw-r--r-- | include/linux/swapops.h | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/include/linux/swapops.h b/include/linux/swapops.h new file mode 100644 index 000000000000..d4c7db35e708 --- /dev/null +++ b/include/linux/swapops.h @@ -0,0 +1,69 @@ +/* + * swapcache pages are stored in the swapper_space radix tree. We want to + * get good packing density in that tree, so the index should be dense in + * the low-order bits. + * + * We arrange the `type' and `offset' fields so that `type' is at the five + * high-order bits of the smp_entry_t and `offset' is right-aligned in the + * remaining bits. + * + * swp_entry_t's are *never* stored anywhere in their arch-dependent format. + */ +#define SWP_TYPE_SHIFT(e) (sizeof(e.val) * 8 - MAX_SWAPFILES_SHIFT) +#define SWP_OFFSET_MASK(e) ((1UL << SWP_TYPE_SHIFT(e)) - 1) + +/* + * Store a type+offset into a swp_entry_t in an arch-independent format + */ +static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset) +{ + swp_entry_t ret; + + ret.val = (type << SWP_TYPE_SHIFT(ret)) | + (offset & SWP_OFFSET_MASK(ret)); + return ret; +} + +/* + * Extract the `type' field from a swp_entry_t. The swp_entry_t is in + * arch-independent format + */ +static inline unsigned swp_type(swp_entry_t entry) +{ + return (entry.val >> SWP_TYPE_SHIFT(entry)); +} + +/* + * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in + * arch-independent format + */ +static inline pgoff_t swp_offset(swp_entry_t entry) +{ + return entry.val & SWP_OFFSET_MASK(entry); +} + +/* + * Convert the arch-dependent pte representation of a swp_entry_t into an + * arch-independent swp_entry_t. + */ +static inline swp_entry_t pte_to_swp_entry(pte_t pte) +{ + swp_entry_t arch_entry; + + BUG_ON(pte_file(pte)); + arch_entry = __pte_to_swp_entry(pte); + return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); +} + +/* + * Convert the arch-independent representation of a swp_entry_t into the + * arch-dependent pte representation. + */ +static inline pte_t swp_entry_to_pte(swp_entry_t entry) +{ + swp_entry_t arch_entry; + + arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); + BUG_ON(pte_file(__swp_entry_to_pte(arch_entry))); + return __swp_entry_to_pte(arch_entry); +} |