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Commit c5dee617 authored by Markus Metzger's avatar Markus Metzger Committed by Ingo Molnar
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x86, bts: memory accounting 



Impact: move the BTS buffer accounting to the mlock bucket

Add alloc_locked_buffer() and free_locked_buffer() functions to mm/mlock.c
to kalloc a buffer and account the locked memory to current.

Account the memory for the BTS buffer to the tracer.

Signed-off-by: default avatarMarkus Metzger <markus.t.metzger@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent bf53de90

arch/x86/kernel/ptrace.c

+34 −11
Original line number Diff line number Diff line
@@ -650,6 +650,24 @@ static int ptrace_bts_drain(struct task_struct *child, 
	return drained;

}



static int ptrace_bts_allocate_buffer(struct task_struct *child, size_t size)

{

	child->bts_buffer = alloc_locked_buffer(size);

	if (!child->bts_buffer)

		return -ENOMEM;



	child->bts_size = size;



	return 0;

}



static void ptrace_bts_free_buffer(struct task_struct *child)

{

	free_locked_buffer(child->bts_buffer, child->bts_size);

	child->bts_buffer = NULL;

	child->bts_size = 0;

}



static int ptrace_bts_config(struct task_struct *child,

			     long cfg_size,

			     const struct ptrace_bts_config __user *ucfg)
@@ -679,14 +697,13 @@ static int ptrace_bts_config(struct task_struct *child, 


	if ((cfg.flags & PTRACE_BTS_O_ALLOC) &&

	    (cfg.size != child->bts_size)) {

		kfree(child->bts_buffer);

		int error;



		child->bts_size = cfg.size;

		child->bts_buffer = kzalloc(cfg.size, GFP_KERNEL);

		if (!child->bts_buffer) {

			child->bts_size = 0;

			return -ENOMEM;

		}

		ptrace_bts_free_buffer(child);



		error = ptrace_bts_allocate_buffer(child, cfg.size);

		if (error < 0)

			return error;

	}



	if (cfg.flags & PTRACE_BTS_O_TRACE)
@@ -701,10 +718,8 @@ static int ptrace_bts_config(struct task_struct *child, 
	if (IS_ERR(child->bts)) {

		int error = PTR_ERR(child->bts);



		kfree(child->bts_buffer);

		ptrace_bts_free_buffer(child);

		child->bts = NULL;

		child->bts_buffer = NULL;

		child->bts_size = 0;



		return error;

	}
@@ -784,6 +799,9 @@ static void ptrace_bts_untrace(struct task_struct *child) 
		ds_release_bts(child->bts);

		child->bts = NULL;



		/* We cannot update total_vm and locked_vm since

		   child's mm is already gone. But we can reclaim the

		   memory. */

		kfree(child->bts_buffer);

		child->bts_buffer = NULL;

		child->bts_size = 0;
@@ -792,7 +810,12 @@ static void ptrace_bts_untrace(struct task_struct *child) 


static void ptrace_bts_detach(struct task_struct *child)

{

	ptrace_bts_untrace(child);

	if (unlikely(child->bts)) {

		ds_release_bts(child->bts);

		child->bts = NULL;



		ptrace_bts_free_buffer(child);

	}

}

#else

static inline void ptrace_bts_fork(struct task_struct *tsk) {}

include/linux/mm.h

+2 −0
Original line number Diff line number Diff line
@@ -1286,5 +1286,7 @@ int vmemmap_populate_basepages(struct page *start_page, 
int vmemmap_populate(struct page *start_page, unsigned long pages, int node);

void vmemmap_populate_print_last(void);



extern void *alloc_locked_buffer(size_t size);

extern void free_locked_buffer(void *buffer, size_t size);

#endif /* __KERNEL__ */

#endif /* _LINUX_MM_H */

mm/mlock.c

+45 −0
Original line number Diff line number Diff line
@@ -667,3 +667,48 @@ void user_shm_unlock(size_t size, struct user_struct *user) 
	spin_unlock(&shmlock_user_lock);

	free_uid(user);

}



void *alloc_locked_buffer(size_t size)

{

	unsigned long rlim, vm, pgsz;

	void *buffer = NULL;



	pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT;



	down_write(&current->mm->mmap_sem);



	rlim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;

	vm   = current->mm->total_vm + pgsz;

	if (rlim < vm)

		goto out;



	rlim = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;

	vm   = current->mm->locked_vm + pgsz;

	if (rlim < vm)

		goto out;



	buffer = kzalloc(size, GFP_KERNEL);

	if (!buffer)

		goto out;



	current->mm->total_vm  += pgsz;

	current->mm->locked_vm += pgsz;



 out:

	up_write(&current->mm->mmap_sem);

	return buffer;

}



void free_locked_buffer(void *buffer, size_t size)

{

	unsigned long pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT;



	down_write(&current->mm->mmap_sem);



	current->mm->total_vm  -= pgsz;

	current->mm->locked_vm -= pgsz;



	up_write(&current->mm->mmap_sem);



	kfree(buffer);

}