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Commit 1cb81b14 authored by Markus Metzger's avatar Markus Metzger Committed by Ingo Molnar
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x86, bts, mm: clean up buffer allocation 



The current mm interface is asymetric. One function allocates a locked
buffer, another function only refunds the memory.

Change this to have two functions for accounting and refunding locked
memory, respectively; and do the actual buffer allocation in ptrace.

[ Impact: refactor BTS buffer allocation code ]

Signed-off-by: default avatarMarkus Metzger <markus.t.metzger@intel.com>
Acked-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090424095143.A30265@sedona.ch.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 7e0bfad2

arch/x86/kernel/ptrace.c

+26 −13
Original line number Diff line number Diff line
@@ -617,17 +617,28 @@ struct bts_context { 
	struct work_struct	work;

};



static inline void alloc_bts_buffer(struct bts_context *context,

				    unsigned int size)

static int alloc_bts_buffer(struct bts_context *context, unsigned int size)

{

	void *buffer;

	void *buffer = NULL;

	int err = -ENOMEM;



	err = account_locked_memory(current->mm, current->signal->rlim, size);

	if (err < 0)

		return err;



	buffer = kzalloc(size, GFP_KERNEL);

	if (!buffer)

		goto out_refund;



	buffer = alloc_locked_buffer(size);

	if (buffer) {

	context->buffer = buffer;

	context->size = size;

	context->mm = get_task_mm(current);

	}



	return 0;



 out_refund:

	refund_locked_memory(current->mm, size);

	return err;

}



static inline void free_bts_buffer(struct bts_context *context)
@@ -638,7 +649,7 @@ static inline void free_bts_buffer(struct bts_context *context) 
	kfree(context->buffer);

	context->buffer = NULL;



	refund_locked_buffer_memory(context->mm, context->size);

	refund_locked_memory(context->mm, context->size);

	context->size = 0;



	mmput(context->mm);
@@ -786,13 +797,15 @@ static int ptrace_bts_config(struct task_struct *child, 
	context->tracer = NULL;



	if ((cfg.flags & PTRACE_BTS_O_ALLOC) && (cfg.size != context->size)) {

		int err;



		free_bts_buffer(context);

		if (!cfg.size)

			return 0;



		alloc_bts_buffer(context, cfg.size);

		if (!context->buffer)

			return -ENOMEM;

		err = alloc_bts_buffer(context, cfg.size);

		if (err < 0)

			return err;

	}



	if (cfg.flags & PTRACE_BTS_O_TRACE)

include/linux/mm.h

+4 −2
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ struct anon_vma; 
struct file_ra_state;

struct user_struct;

struct writeback_control;

struct rlimit;



#ifndef CONFIG_DISCONTIGMEM          /* Don't use mapnrs, do it properly */

extern unsigned long max_mapnr;
@@ -1319,7 +1320,8 @@ 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 refund_locked_buffer_memory(struct mm_struct *mm, size_t size);

extern int account_locked_memory(struct mm_struct *mm, struct rlimit *rlim,

				 size_t size);

extern void refund_locked_memory(struct mm_struct *mm, size_t size);

#endif /* __KERNEL__ */

#endif /* _LINUX_MM_H */

mm/mlock.c

+17 −19
Original line number Diff line number Diff line
@@ -629,38 +629,36 @@ void user_shm_unlock(size_t size, struct user_struct *user) 
	free_uid(user);

}



void *alloc_locked_buffer(size_t size)

int account_locked_memory(struct mm_struct *mm, struct rlimit *rlim,

			  size_t size)

{

	unsigned long rlim, vm, pgsz;

	void *buffer = NULL;

	unsigned long lim, vm, pgsz;

	int error = -ENOMEM;



	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;

	down_write(&mm->mmap_sem);



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

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

	if (rlim < vm)

	lim = rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;

	vm   = mm->total_vm + pgsz;

	if (lim < vm)

		goto out;



	buffer = kzalloc(size, GFP_KERNEL);

	if (!buffer)

	lim = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;

	vm   = mm->locked_vm + pgsz;

	if (lim < vm)

		goto out;



	current->mm->total_vm  += pgsz;

	current->mm->locked_vm += pgsz;

	mm->total_vm  += pgsz;

	mm->locked_vm += pgsz;



	error = 0;

 out:

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

	return buffer;

	up_write(&mm->mmap_sem);

	return error;

}



void refund_locked_buffer_memory(struct mm_struct *mm, size_t size)

void refund_locked_memory(struct mm_struct *mm, size_t size)

{

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