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Date: Fri, 24 Apr 2009 09:51:43 +0200
From: Markus Metzger <markus.t.metzger@...el.com>
To: a.p.zijlstra@...llo.nl, akpm@...ux-foundation.org
Cc: markus.t.metzger@...el.com, markus.t.metzger@...il.com,
roland@...hat.com, eranian@...glemail.com, oleg@...hat.com,
juan.villacis@...el.com, ak@...ux.jf.intel.com,
linux-kernel@...r.kernel.org, mingo@...e.hu, tglx@...utronix.de,
hpa@...or.com
Subject: [rfc 1/2] x86, bts, mm: 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.
CC: Peter Zijlstra <a.p.zijlstra@...llo.nl>
CC: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Markus Metzger <markus.t.metzger@...el.com>
---
arch/x86/kernel/ptrace.c | 39 26 + 13 - 0 !
include/linux/mm.h | 6 4 + 2 - 0 !
mm/mlock.c | 36 17 + 19 - 0 !
3 files changed, 47 insertions(+), 34 deletions(-)
Index: b/include/linux/mm.h
===================================================================
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -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 pa
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 */
Index: b/mm/mlock.c
===================================================================
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -629,38 +629,36 @@ void user_shm_unlock(size_t size, struct
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(¤t->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(¤t->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;
Index: b/arch/x86/kernel/ptrace.c
===================================================================
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -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;
- buffer = alloc_locked_buffer(size);
- if (buffer) {
- context->buffer = buffer;
- context->size = size;
- context->mm = get_task_mm(current);
- }
+ 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;
+
+ 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(struc
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
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)
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