[QUICKLIST 3/4] Quicklist support for x86_64

Christoph Lameter
2007-04-09T18:25:20Z

Conver x86_64 to using quicklists

This adds caching of pgds and puds, pmds, pte. That way we can
avoid costly zeroing and initialization of special mappings in the
pgd.

A second quicklist is useful to separate out PGD handling. We can carry
the initialized pgds over to the next process needing them.

Also clean up the pgd_list handling to use regular list macros.
There is no need anymore to avoid the lru field.

Move the add/removal of the pgds to the pgdlist into the
constructor / destructor. That way the implementation is
congruent with i386.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

---
arch/x86_64/Kconfig | 4 ++
arch/x86_64/kernel/process.c | 1
arch/x86_64/kernel/smp.c | 2 -
arch/x86_64/mm/fault.c | 5 +-
include/asm-x86_64/pgalloc.h | 76 +++++++++++++++++++++----------------------
include/asm-x86_64/pgtable.h | 3 -
mm/Kconfig | 5 ++
7 files changed, 52 insertions(+), 44 deletions(-)

Index: linux-2.6.21-rc5-mm4/arch/x86_64/Kconfig
===================================================================
--- linux-2.6.21-rc5-mm4.orig/arch/x86_64/Kconfig 2007-04-07 18:09:17.000000000 -0700
+++ linux-2.6.21-rc5-mm4/arch/x86_64/Kconfig 2007-04-07 18:09:30.000000000 -0700
@@ -56,6 +56,14 @@
bool
default y

+config QUICKLIST
+ bool
+ default y
+
+config NR_QUICK
+ int
+ default 2
+
config ISA
bool

Index: linux-2.6.21-rc5-mm4/include/asm-x86_64/pgalloc.h
===================================================================
--- linux-2.6.21-rc5-mm4.orig/include/asm-x86_64/pgalloc.h 2007-04-07 18:07:47.000000000 -0700
+++ linux-2.6.21-rc5-mm4/include/asm-x86_64/pgalloc.h 2007-04-07 18:47:03.000000000 -0700
@@ -4,6 +4,10 @@
#include <asm/pda.h>
#include <linux/threads.h>
#include <linux/mm.h>
+#include <linux/quicklist.h>
+
+#define QUICK_PGD 0 /* We preserve special mappings over free */
+#define QUICK_PT 1 /* Other page table pages that are zero on free */

#define pmd_populate_kernel(mm, pmd, pte) \
set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte)))
@@ -20,23 +24,23 @@
static inline void pmd_free(pmd_t *pmd)
{
BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
- free_page((unsigned long)pmd);
+ quicklist_free(QUICK_PT, NULL, pmd);
}

static inline pmd_t *pmd_alloc_one (struct mm_struct *mm, unsigned long addr)
{
- return (pmd_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
+ return (pmd_t *)quicklist_alloc(QUICK_PT, GFP_KERNEL|__GFP_REPEAT, NULL);
}

static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
{
- return (pud_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
+ return (pud_t *)quicklist_alloc(QUICK_PT, GFP_KERNEL|__GFP_REPEAT, NULL);
}

static inline void pud_free (pud_t *pud)
{
BUG_ON((unsigned long)pud & (PAGE_SIZE-1));
- free_page((unsigned long)pud);
+ quicklist_free(QUICK_PT, NULL, pud);
}

static inline void pgd_list_add(pgd_t *pgd)
@@ -57,41 +61,57 @@
spin_unlock(&pgd_lock);
}

-static inline pgd_t *pgd_alloc(struct mm_struct *mm)
+static inline void pgd_ctor(void *x)
{
unsigned boundary;
- pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
- if (!pgd)
- return NULL;
- pgd_list_add(pgd);
+ pgd_t *pgd = x;
+ struct page *page = virt_to_page(pgd);
+
/*
* Copy kernel pointers in from init.
- * Could keep a freelist or slab cache of those because the kernel
- * part never changes.
*/
boundary = pgd_index(__PAGE_OFFSET);
- memset(pgd, 0, boundary * sizeof(pgd_t));
memcpy(pgd + boundary,
- init_level4_pgt + boundary,
- (PTRS_PER_PGD - boundary) * sizeof(pgd_t));
+ init_level4_pgt + boundary,
+ (PTRS_PER_PGD - boundary) * sizeof(pgd_t));
+
+ spin_lock(&pgd_lock);
+ list_add(&page->lru, &pgd_list);
+ spin_unlock(&pgd_lock);
+}
+
+static inline void pgd_dtor(void *x)
+{
+ pgd_t *pgd = x;
+ struct page *page = virt_to_page(pgd);
+
+ spin_lock(&pgd_lock);
+ list_del(&page->lru);
+ spin_unlock(&pgd_lock);
+}
+
+static inline pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+ pgd_t *pgd = (pgd_t *)quicklist_alloc(QUICK_PGD,
+ GFP_KERNEL|__GFP_REPEAT, pgd_ctor);
return pgd;
}

static inline void pgd_free(pgd_t *pgd)
{
BUG_ON((unsigned long)pgd & (PAGE_SIZE-1));
- pgd_list_del(pgd);
- free_page((unsigned long)pgd);
+ quicklist_free(QUICK_PGD, pgd_dtor, pgd);
}

static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
- return (pte_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
+ return (pte_t *)quicklist_alloc(QUICK_PT, GFP_KERNEL|__GFP_REPEAT, NULL);
}

static inline struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
- void *p = (void *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
+ void *p = (void *)quicklist_alloc(QUICK_PT, GFP_KERNEL|__GFP_REPEAT, NULL);
+
if (!p)
return NULL;
return virt_to_page(p);
@@ -103,17 +123,22 @@
static inline void pte_free_kernel(pte_t *pte)
{
BUG_ON((unsigned long)pte & (PAGE_SIZE-1));
- free_page((unsigned long)pte);
+ quicklist_free(QUICK_PT, NULL, pte);
}

static inline void pte_free(struct page *pte)
{
- __free_page(pte);
-}
+ quicklist_free_page(QUICK_PT, NULL, pte);
+}

-#define __pte_free_tlb(tlb,pte) tlb_remove_page((tlb),(pte))
+#define __pte_free_tlb(tlb,pte) quicklist_free_page(QUICK_PT, NULL,(pte))

-#define __pmd_free_tlb(tlb,x) tlb_remove_page((tlb),virt_to_page(x))
-#define __pud_free_tlb(tlb,x) tlb_remove_page((tlb),virt_to_page(x))
+#define __pmd_free_tlb(tlb,x) quicklist_free(QUICK_PT, NULL, (x))
+#define __pud_free_tlb(tlb,x) quicklist_free(QUICK_PT, NULL, (x))

+static inline void check_pgt_cache(void)
+{
+ quicklist_trim(QUICK_PGD, pgd_dtor, 25, 16);
+ quicklist_trim(QUICK_PT, NULL, 25, 16);
+}
#endif /* _X86_64_PGALLOC_H */
Index: linux-2.6.21-rc5-mm4/arch/x86_64/kernel/process.c
===================================================================
--- linux-2.6.21-rc5-mm4.orig/arch/x86_64/kernel/process.c 2007-04-07 18:07:47.000000000 -0700
+++ linux-2.6.21-rc5-mm4/arch/x86_64/kernel/process.c 2007-04-07 18:09:30.000000000 -0700
@@ -207,6 +207,7 @@
if (__get_cpu_var(cpu_idle_state))
__get_cpu_var(cpu_idle_state) = 0;

+ check_pgt_cache();
rmb();
idle = pm_idle;
if (!idle)
Index: linux-2.6.21-rc5-mm4/arch/x86_64/kernel/smp.c
===================================================================
--- linux-2.6.21-rc5-mm4.orig/arch/x86_64/kernel/smp.c 2007-04-07 18:07:47.000000000 -0700
+++ linux-2.6.21-rc5-mm4/arch/x86_64/kernel/smp.c 2007-04-07 18:09:30.000000000 -0700
@@ -241,7 +241,7 @@
}
if (!cpus_empty(cpu_mask))
flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
-
+ check_pgt_cache();
preempt_enable();
}
EXPORT_SYMBOL(flush_tlb_mm);
Index: linux-2.6.21-rc5-mm4/include/asm-x86_64/pgtable.h
===================================================================
--- linux-2.6.21-rc5-mm4.orig/include/asm-x86_64/pgtable.h 2007-04-07 18:07:47.000000000 -0700
+++ linux-2.6.21-rc5-mm4/include/asm-x86_64/pgtable.h 2007-04-07 18:09:30.000000000 -0700
@@ -424,7 +424,6 @@
#define HAVE_ARCH_UNMAPPED_AREA

#define pgtable_cache_init() do { } while (0)
-#define check_pgt_cache() do { } while (0)

#define PAGE_AGP PAGE_KERNEL_NOCACHE
#define HAVE_PAGE_AGP 1