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Read a whole page at a time.

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Sat Apr 16 19:51:48 2005  Soeren Sandmann  <sandmann@redhat.com>

	* sysprof-module.c (read_user_space): Read a whole page at a time.
This commit is contained in:
Soeren Sandmann
2005-04-16 23:57:00 +00:00
committed by Søren Sandmann Pedersen
parent 2b0ca11c6c
commit 023ce06615
2 changed files with 51 additions and 25 deletions
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4
ChangeLog
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@ -1,3 +1,7 @@
Sat Apr 16 19:51:48 2005 Soeren Sandmann <sandmann@redhat.com>
* sysprof-module.c (read_user_space): Read a whole page at a time.
Sat Apr 16 14:15:55 2005 Soeren Sandmann <sandmann@redhat.com>
* TODO: Update

72
sysprof-module.c
View File

@ -61,21 +61,10 @@ typedef struct userspace_reader userspace_reader;
struct userspace_reader
{
struct task_struct *task;
unsigned long user_page;
unsigned long kernel_page;
struct page *page;
unsigned long cache_address;
unsigned long *cache;
};
static void
init_userspace_reader (userspace_reader *reader,
struct task_struct *task)
{
reader->task = task;
reader->user_page = 0;
reader->kernel_page = 0;
reader->page = NULL;
}
/* This function was mostly cutted and pasted from ptrace.c
*/
@ -149,19 +138,48 @@ x_access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int
return buf - old_buf;
}
static int
init_userspace_reader (userspace_reader *reader,
struct task_struct *task)
{
reader->task = task;
reader->cache = kmalloc (PAGE_SIZE, GFP_KERNEL);
if (!reader->cache)
return 0;
reader->cache_address = 0x0;
return 1;
}
static int
read_user_space (userspace_reader *reader,
unsigned long address,
unsigned long *result)
{
return x_access_process_vm(reader->task, address, result, 4, 0);
unsigned long cache_address = reader->cache_address;
int index, r;
if (!cache_address || cache_address != (address & PAGE_MASK)) {
cache_address = address & PAGE_MASK;
r = x_access_process_vm (reader->task, cache_address,
reader->cache, PAGE_SIZE, 0);
if (r != PAGE_SIZE)
return 0;
reader->cache_address = cache_address;
}
index = (address - cache_address) / sizeof (unsigned long);
*result = reader->cache[index];
return 1;
}
static void
done_userspace_reader (userspace_reader *reader)
{
if (reader->user_page)
kunmap (reader->page);
kfree (reader->cache);
}
typedef struct StackFrame StackFrame;
@ -214,15 +232,19 @@ generate_stack_trace(struct task_struct *task,
addr = regs->ebp;
init_userspace_reader (&reader, task);
while (i < SYSPROF_MAX_ADDRESSES && read_frame (&reader, addr, &frame) &&
addr < START_OF_STACK && addr >= regs->esp) {
if (init_userspace_reader (&reader, task))
{
while (i < SYSPROF_MAX_ADDRESSES &&
read_frame (&reader, addr, &frame) &&
addr < START_OF_STACK && addr >= regs->esp)
{
trace->addresses[i++] = (void *)frame.return_address;
addr = frame.next;
}
trace->addresses[i++] = (void *)frame.return_address;
addr = frame.next;
done_userspace_reader (&reader);
}
done_userspace_reader (&reader);
trace->n_addresses = i;
if (i == SYSPROF_MAX_ADDRESSES)
trace->truncated = 1;
@ -230,8 +252,6 @@ generate_stack_trace(struct task_struct *task,
trace->truncated = 0;
}
struct work_struct work;
DECLARE_WAIT_QUEUE_HEAD (wait_to_be_scanned);
static void
@ -250,6 +270,8 @@ do_generate (void *data)
mod_timer(&timer, jiffies + INTERVAL);
}
struct work_struct work;
static void
on_timer(unsigned long dong)
{