First of a sequence of six patches, extending Dave McCracken's
objrmap to handle anonymous memory too, eliminating pte_chains.
Based upon 2.5.65-mm2, the aggregate has
81 files changed, 1140 insertions(+), 1634 deletions(-)
anobjrmap 1/6 create include/linux/rmap.h
anobjrmap 2/6 free page->mapping for use by anon
anobjrmap 3/6 remove pte-pointer-based rmap
anobjrmap 4/6 add anonmm to track anonymous pages
anonjrmap 5/6 virtual address chains for odd cases
anonjrmap 6/6 updates to arches other than i386
I've not done any timings, hope others can do that better than
I would. My guess is that Dave has already covered the worst
cases, but this should cut the rmap overhead when forking.
anobjrmap 1/6 create include/linux/rmap.h
Start small: linux/rmap-locking.h has already gathered some
declarations unrelated to locking, then the rest of the rmap
declarations were over in linux/swap.h: gather them all
together in linux/rmap.h.
Omit SWAP_ERROR (unused), page_over_rsslimit (non-existent).
Fix a couple of missed unlocks in rmap.c page_convert_anon,
before the whole function is removed in the next patch.
fs/exec.c | 2 -
include/linux/rmap-locking.h | 49 ----------------------------
include/linux/rmap.h | 73 +++++++++++++++++++++++++++++++++++++++++++
include/linux/swap.h | 19 -----------
mm/fremap.c | 2 -
mm/memory.c | 2 -
mm/mremap.c | 2 -
mm/rmap.c | 9 +----
mm/swapfile.c | 2 -
mm/vmscan.c | 3 -
10 files changed, 82 insertions(+), 81 deletions(-)
--- 2.5.65-mm2/fs/exec.c Wed Mar 19 11:05:11 2003
+++ anobjrmap1/fs/exec.c Thu Mar 20 17:09:50 2003
@@ -45,7 +45,7 @@
#include <linux/ptrace.h>
#include <linux/mount.h>
#include <linux/security.h>
-#include <linux/rmap-locking.h>
+#include <linux/rmap.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
--- 2.5.65-mm2/include/linux/rmap-locking.h Wed Mar 19 11:05:16 2003
+++ anobjrmap1/include/linux/rmap-locking.h Thu Jan 1 01:00:00 1970
@@ -1,49 +0,0 @@
-/*
- * include/linux/rmap-locking.h
- *
- * Locking primitives for exclusive access to a page's reverse-mapping
- * pte chain.
- */
-
-#include <linux/slab.h>
-
-struct pte_chain;
-extern kmem_cache_t *pte_chain_cache;
-
-static inline void pte_chain_lock(struct page *page)
-{
- /*
- * Assuming the lock is uncontended, this never enters
- * the body of the outer loop. If it is contended, then
- * within the inner loop a non-atomic test is used to
- * busywait with less bus contention for a good time to
- * attempt to acquire the lock bit.
- */
- preempt_disable();
-#ifdef CONFIG_SMP
- while (test_and_set_bit(PG_chainlock, &page->flags)) {
- while (test_bit(PG_chainlock, &page->flags))
- cpu_relax();
- }
-#endif
-}
-
-static inline void pte_chain_unlock(struct page *page)
-{
-#ifdef CONFIG_SMP
- smp_mb__before_clear_bit();
- clear_bit(PG_chainlock, &page->flags);
-#endif
- preempt_enable();
-}
-
-struct pte_chain *pte_chain_alloc(int gfp_flags);
-void __pte_chain_free(struct pte_chain *pte_chain);
-
-static inline void pte_chain_free(struct pte_chain *pte_chain)
-{
- if (pte_chain)
- __pte_chain_free(pte_chain);
-}
-
-void page_convert_anon(struct page *page);
--- 2.5.65-mm2/include/linux/rmap.h Thu Jan 1 01:00:00 1970
+++ anobjrmap1/include/linux/rmap.h Thu Mar 20 17:09:50 2003
@@ -0,0 +1,73 @@
+#ifndef _LINUX_RMAP_H
+#define _LINUX_RMAP_H
+/*
+ * Declarations for Reverse Mapping functions in mm/rmap.c
+ * Its structures are declared within that file.
+ */
+#include <linux/config.h>
+#include <linux/linkage.h>
+
+#ifdef CONFIG_MMU
+
+struct pte_chain;
+struct pte_chain *pte_chain_alloc(int gfp_flags);
+void __pte_chain_free(struct pte_chain *pte_chain);
+
+static inline void pte_chain_free(struct pte_chain *pte_chain)
+{
+ if (pte_chain)
+ __pte_chain_free(pte_chain);
+}
+
+struct pte_chain *FASTCALL(
+ page_add_rmap(struct page *, pte_t *, struct pte_chain *));
+void FASTCALL(page_remove_rmap(struct page *, pte_t *));
+void page_convert_anon(struct page *page);
+
+/*
+ * Called from mm/vmscan.c to handle paging out
+ */
+int FASTCALL(page_referenced(struct page *));
+int FASTCALL(try_to_unmap(struct page *));
+
+/*
+ * Return values of try_to_unmap
+ */
+#define SWAP_SUCCESS 0
+#define SWAP_AGAIN 1
+#define SWAP_FAIL 2
+
+#else /* !CONFIG_MMU */
+
+#define page_referenced(page) TestClearPageReferenced(page)
+
+#endif /* CONFIG_MMU */
+
+static inline void pte_chain_lock(struct page *page)
+{
+ /*
+ * Assuming the lock is uncontended, this never enters
+ * the body of the outer loop. If it is contended, then
+ * within the inner loop a non-atomic test is used to
+ * busywait with less bus contention for a good time to
+ * attempt to acquire the lock bit.
+ */
+ preempt_disable();
+#ifdef CONFIG_SMP
+ while (test_and_set_bit(PG_chainlock, &page->flags)) {
+ while (test_bit(PG_chainlock, &page->flags))
+ cpu_relax();
+ }
+#endif
+}
+
+static inline void pte_chain_unlock(struct page *page)
+{
+#ifdef CONFIG_SMP
+ smp_mb__before_clear_bit();
+ clear_bit(PG_chainlock, &page->flags);
+#endif
+ preempt_enable();
+}
+
+#endif /* _LINUX_RMAP_H */
--- 2.5.65-mm2/include/linux/swap.h Wed Mar 5 07:26:34 2003
+++ anobjrmap1/include/linux/swap.h Thu Mar 20 17:09:50 2003
@@ -69,7 +69,6 @@
#ifdef __KERNEL__
struct address_space;
-struct pte_chain;
struct sysinfo;
struct writeback_control;
struct zone;
@@ -167,27 +166,9 @@
extern int shrink_all_memory(int);
extern int vm_swappiness;
-/* linux/mm/rmap.c */
#ifdef CONFIG_MMU
-int FASTCALL(page_referenced(struct page *));
-struct pte_chain *FASTCALL(page_add_rmap(struct page *, pte_t *,
- struct pte_chain *));
-void FASTCALL(page_remove_rmap(struct page *, pte_t *));
-int FASTCALL(try_to_unmap(struct page *));
-int FASTCALL(page_over_rsslimit(struct page *));
-
-/* return values of try_to_unmap */
-#define SWAP_SUCCESS 0
-#define SWAP_AGAIN 1
-#define SWAP_FAIL 2
-#define SWAP_ERROR 3
-
/* linux/mm/shmem.c */
extern int shmem_unuse(swp_entry_t entry, struct page *page);
-
-#else
-#define page_referenced(page) \
- TestClearPageReferenced(page)
#endif /* CONFIG_MMU */
#ifdef CONFIG_SWAP
--- 2.5.65-mm2/mm/fremap.c Wed Mar 19 11:05:16 2003
+++ anobjrmap1/mm/fremap.c Thu Mar 20 17:09:50 2003
@@ -11,7 +11,7 @@
#include <linux/mman.h>
#include <linux/pagemap.h>
#include <linux/swapops.h>
-#include <linux/rmap-locking.h>
+#include <linux/rmap.h>
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
--- 2.5.65-mm2/mm/memory.c Wed Mar 19 11:05:16 2003
+++ anobjrmap1/mm/memory.c Thu Mar 20 17:09:50 2003
@@ -44,7 +44,7 @@
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/vcache.h>
-#include <linux/rmap-locking.h>
+#include <linux/rmap.h>
#include <asm/pgalloc.h>
#include <asm/rmap.h>
--- 2.5.65-mm2/mm/mremap.c Tue Mar 18 07:38:45 2003
+++ anobjrmap1/mm/mremap.c Thu Mar 20 17:09:50 2003
@@ -15,7 +15,7 @@
#include <linux/swap.h>
#include <linux/fs.h>
#include <linux/highmem.h>
-#include <linux/rmap-locking.h>
+#include <linux/rmap.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
--- 2.5.65-mm2/mm/rmap.c Wed Mar 19 11:05:16 2003
+++ anobjrmap1/mm/rmap.c Thu Mar 20 17:09:50 2003
@@ -25,7 +25,7 @@
#include <linux/swapops.h>
#include <linux/slab.h>
#include <linux/init.h>
-#include <linux/rmap-locking.h>
+#include <linux/rmap.h>
#include <linux/cache.h>
#include <linux/percpu.h>
@@ -677,7 +677,6 @@
* SWAP_SUCCESS - we succeeded in removing all mappings
* SWAP_AGAIN - we missed a trylock, try again later
* SWAP_FAIL - the page is unswappable
- * SWAP_ERROR - an error occurred
*/
int try_to_unmap(struct page * page)
{
@@ -754,9 +753,6 @@
case SWAP_FAIL:
ret = SWAP_FAIL;
goto out;
- case SWAP_ERROR:
- ret = SWAP_ERROR;
- goto out;
}
}
}
@@ -812,6 +808,7 @@
*/
if (mapcount < page->pte.mapcount) {
pte_chain_unlock(page);
+ up(&mapping->i_shared_sem);
goto retry;
} else if ((mapcount > page->pte.mapcount) && (mapcount > 1)) {
mapcount = page->pte.mapcount;
@@ -827,7 +824,7 @@
SetPageAnon(page);
if (mapcount == 0)
- goto out;
+ goto out_unlock;
else if (mapcount == 1) {
SetPageDirect(page);
page->pte.direct = 0;
--- 2.5.65-mm2/mm/swapfile.c Wed Mar 19 11:05:16 2003
+++ anobjrmap1/mm/swapfile.c Thu Mar 20 17:09:50 2003
@@ -20,7 +20,7 @@
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/init.h>
-#include <linux/rmap-locking.h>
+#include <linux/rmap.h>
#include <asm/pgtable.h>
#include <linux/swapops.h>
--- 2.5.65-mm2/mm/vmscan.c Tue Feb 18 02:14:32 2003
+++ anobjrmap1/mm/vmscan.c Thu Mar 20 17:09:50 2003
@@ -26,7 +26,7 @@
#include <linux/mm_inline.h>
#include <linux/pagevec.h>
#include <linux/backing-dev.h>
-#include <linux/rmap-locking.h>
+#include <linux/rmap.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
@@ -284,7 +284,6 @@
*/
if (page_mapped(page) && mapping) {
switch (try_to_unmap(page)) {
- case SWAP_ERROR:
case SWAP_FAIL:
pte_chain_unlock(page);
goto activate_locked;
-
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This archive was generated by hypermail 2b29 : Sun Mar 23 2003 - 22:00:33 EST