[patch 08/26] Xen-paravirt_ops: add hooks to intercept mm creation and destruction

Jeremy Fitzhardinge
2007-02-27T08:45:24Z

[-- Attachment #1: mm-lifetime-hooks.patch --]
[-- Type: text/plain, Size: 4176 bytes --]

Add hooks to allow a paravirt implementation to track the lifetime of
an mm.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: linux-arch@vger.kernel.org
---
arch/i386/kernel/paravirt.c | 4 ++++
include/asm-i386/mmu_context.h | 8 ++++++--
include/asm-i386/paravirt.h | 25 +++++++++++++++++++++++++
include/linux/sched.h | 6 ++++++
kernel/fork.c | 2 ++
mm/mmap.c | 3 +++
6 files changed, 46 insertions(+), 2 deletions(-)

===================================================================
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -700,6 +700,10 @@ struct paravirt_ops paravirt_ops = {
.irq_enable_sysexit = native_irq_enable_sysexit,
.iret = native_iret,

+ .dup_mmap = paravirt_nop,
+ .exit_mmap = paravirt_nop,
+ .activate_mm = paravirt_nop,
+
.startup_ipi_hook = paravirt_nop,
};

===================================================================
--- a/include/asm-i386/mmu_context.h
+++ b/include/asm-i386/mmu_context.h
@@ -5,6 +5,7 @@
#include <asm/atomic.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
+#include <asm/paravirt.h>

/*
* Used for LDT copy/destruction.
@@ -65,7 +66,10 @@ static inline void switch_mm(struct mm_s
#define deactivate_mm(tsk, mm) \
asm("movl %0,%%gs": :"r" (0));

-#define activate_mm(prev, next) \
- switch_mm((prev),(next),NULL)
+#define activate_mm(prev, next) \
+ do { \
+ arch_activate_mm(prev, next); \
+ switch_mm((prev),(next),NULL); \
+ } while(0);

#endif
===================================================================
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -123,6 +123,12 @@ struct paravirt_ops
void (*io_delay)(void);
void (*const_udelay)(unsigned long loops);

+ void (*activate_mm)(struct mm_struct *prev,
+ struct mm_struct *next);
+ void (*dup_mmap)(struct mm_struct *oldmm,
+ struct mm_struct *mm);
+ void (*exit_mmap)(struct mm_struct *mm);
+
#ifdef CONFIG_X86_LOCAL_APIC
void (*apic_write)(unsigned long reg, unsigned long v);
void (*apic_write_atomic)(unsigned long reg, unsigned long v);
@@ -426,6 +432,24 @@ static inline void startup_ipi_hook(int
}
#endif

+#define __HAVE_ARCH_MM_LIFETIME
+static inline void arch_activate_mm(struct mm_struct *prev,
+ struct mm_struct *next)
+{
+ paravirt_ops.activate_mm(prev, next);
+}
+
+static inline void arch_dup_mmap(struct mm_struct *oldmm,
+ struct mm_struct *mm)
+{
+ paravirt_ops.dup_mmap(oldmm, mm);
+}
+
+static inline void arch_exit_mmap(struct mm_struct *mm)
+{
+ paravirt_ops.exit_mmap(mm);
+}
+
#define __flush_tlb() paravirt_ops.flush_tlb_user()
#define __flush_tlb_global() paravirt_ops.flush_tlb_kernel()
#define __flush_tlb_single(addr) paravirt_ops.flush_tlb_single(addr)
@@ -673,5 +697,6 @@ static inline void paravirt_pagetable_se
set_pgd(&base[0], base[USER_PTRS_PER_PGD]);
#endif
}
+
#endif /* CONFIG_PARAVIRT */
#endif /* __ASM_PARAVIRT_H */
===================================================================
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -374,6 +374,12 @@ struct mm_struct {
rwlock_t ioctx_list_lock;
struct kioctx *ioctx_list;
};
+
+#ifndef __HAVE_ARCH_MM_LIFETIME
+#define arch_activate_mm(prev, next) do {} while(0)
+#define arch_dup_mmap(oldmm, mm) do {} while(0)
+#define arch_exit_mmap(mm) do {} while(0)
+#endif

struct sighand_struct {
atomic_t count;
===================================================================
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -286,6 +286,8 @@ static inline int dup_mmap(struct mm_str
if (retval)
goto out;
}
+ /* a new mm has just been created */
+ arch_dup_mmap(oldmm, mm);
retval = 0;
out:
up_write(&mm->mmap_sem);
===================================================================
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1976,6 +1976,9 @@ void exit_mmap(struct mm_struct *mm)
struct vm_area_struct *vma = mm->mmap;
unsigned long nr_accounted = 0;
unsigned long end;
+
+ /* mm's last user has gone, and its about to be pulled down */
+ arch_exit_mmap(mm);

lru_add_drain();
flush_cache_mm(mm);

--