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x86/mm: Give each mm TLB flush generation a unique ID

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commit f39681ed0f48498b80455095376f11535feea332 upstream.

This adds two new variables to mmu_context_t: ctx_id and tlb_gen.
ctx_id uniquely identifies the mm_struct and will never be reused.
For a given mm_struct (and hence ctx_id), tlb_gen is a monotonic
count of the number of times that a TLB flush has been requested.
The pair (ctx_id, tlb_gen) can be used as an identifier for TLB
flush actions and will be used in subsequent patches to reliably
determine whether all needed TLB flushes have occurred on a given
CPU.

This patch is split out for ease of review.  By itself, it has no
real effect other than creating and updating the new variables.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Nadav Amit <nadav.amit@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/413a91c24dab3ed0caa5f4e4d017d87b0857f920.1498751203.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu>
Reviewed-by: Matt Helsley (VMware) <matt.helsley@gmail.com>
Reviewed-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Bo Gan <ganb@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andy Lutomirski 2018-07-14 02:32:07 -07:00 • committed by Greg Kroah-Hartman
parent 58ac8c59db
commit 937dad078f
3 changed files with 19 additions and 2 deletions
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15
arch/x86/include/asm/mmu.h
View file

@ -3,12 +3,18 @@
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/atomic.h>
/*
* The x86 doesn't have a mmu context, but
* we put the segment information here.
* x86 has arch-specific MMU state beyond what lives in mm_struct.
*/
typedef struct {
/*
* ctx_id uniquely identifies this mm_struct. A ctx_id will never
* be reused, and zero is not a valid ctx_id.
*/
u64 ctx_id;
#ifdef CONFIG_MODIFY_LDT_SYSCALL
struct ldt_struct *ldt;
#endif
@ -24,6 +30,11 @@ typedef struct {
atomic_t perf_rdpmc_allowed; /* nonzero if rdpmc is allowed */
} mm_context_t;
#define INIT_MM_CONTEXT(mm) \
.context = { \
.ctx_id = 1, \
}
void leave_mm(int cpu);
#endif /* _ASM_X86_MMU_H */

4
arch/x86/include/asm/mmu_context.h
View file

@ -11,6 +11,9 @@
#include <asm/tlbflush.h>
#include <asm/paravirt.h>
#include <asm/mpx.h>
extern atomic64_t last_mm_ctx_id;
#ifndef CONFIG_PARAVIRT
static inline void paravirt_activate_mm(struct mm_struct *prev,
struct mm_struct *next)
@ -105,6 +108,7 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
static inline int init_new_context(struct task_struct *tsk,
struct mm_struct *mm)
{
mm->context.ctx_id = atomic64_inc_return(&last_mm_ctx_id);
init_new_context_ldt(tsk, mm);
return 0;
}

2
arch/x86/mm/tlb.c
View file

@ -29,6 +29,8 @@
* Implement flush IPI by CALL_FUNCTION_VECTOR, Alex Shi
*/
atomic64_t last_mm_ctx_id = ATOMIC64_INIT(1);
struct flush_tlb_info {
struct mm_struct *flush_mm;
unsigned long flush_start;