diff options
| author | Andrew Morton <akpm@zip.com.au> | 2002-07-18 21:09:02 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@home.transmeta.com> | 2002-07-18 21:09:02 -0700 |
| commit | 6a2ea3382b534e937ba2153f4a0c6021e04a1ef5 (patch) | |
| tree | ee967db238da26f5335651871b04ff1b3a75594e /include/linux | |
| parent | fa08cc8377bf0942822c468cf26581012e69c9c9 (diff) | |
[PATCH] avoid allocating pte_chains for unshared pages
Patch from David McCracken. It is an optimisation to the rmap
pte_chains.
In the common case where a page is mapped by only a single pte, we
don't need to allocate a pte_chain structure. Just make the page's
pte_chain pointer point straight at that pte and flag this with
PG_direct.
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/mm.h | 5 | ||||
| -rw-r--r-- | include/linux/page-flags.h | 12 |
2 files changed, 14 insertions, 3 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 0c0b6d41dbb0..c470238148b6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -157,8 +157,11 @@ struct page { updated asynchronously */ struct list_head lru; /* Pageout list, eg. active_list; protected by pagemap_lru_lock !! */ - struct pte_chain * pte_chain; /* Reverse pte mapping pointer. + union { + struct pte_chain * chain; /* Reverse pte mapping pointer. * protected by PG_chainlock */ + pte_t * direct; + } pte; unsigned long private; /* mapping-private opaque data */ /* diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 7cdd56c8cc3e..a1efdff4d23c 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -64,8 +64,10 @@ #define PG_private 12 /* Has something at ->private */ #define PG_writeback 13 /* Page is under writeback */ -#define PG_nosave 15 /* Used for system suspend/resume */ -#define PG_chainlock 16 /* lock bit for ->pte_chain */ +#define PG_nosave 14 /* Used for system suspend/resume */ +#define PG_chainlock 15 /* lock bit for ->pte_chain */ + +#define PG_direct 16 /* ->pte_chain points directly at pte */ /* * Global page accounting. One instance per CPU. @@ -217,6 +219,12 @@ extern void get_page_state(struct page_state *ret); #define ClearPageNosave(page) clear_bit(PG_nosave, &(page)->flags) #define TestClearPageNosave(page) test_and_clear_bit(PG_nosave, &(page)->flags) +#define PageDirect(page) test_bit(PG_direct, &(page)->flags) +#define SetPageDirect(page) set_bit(PG_direct, &(page)->flags) +#define TestSetPageDirect(page) test_and_set_bit(PG_direct, &(page)->flags) +#define ClearPageDirect(page) clear_bit(PG_direct, &(page)->flags) +#define TestClearPageDirect(page) test_and_clear_bit(PG_direct, &(page)->flags) + /* * inlines for acquisition and release of PG_chainlock */ |