* [PATCH 1/1] TTY: tty_buffer, warn on leaks
@ 2013-11-11 20:05 Jiri Slaby
2013-11-11 23:13 ` Peter Hurley
0 siblings, 1 reply; 3+ messages in thread
From: Jiri Slaby @ 2013-11-11 20:05 UTC (permalink / raw)
To: gregkh; +Cc: jirislaby, linux-kernel, Jiri Slaby
When we leak something, warn about that. For that we need to account
the memory used also in the free_all method. It is handled elsewhere
correctly.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/tty/tty_buffer.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 5f08c39e76ab..20cb9492dbf8 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -115,21 +115,27 @@ void tty_buffer_free_all(struct tty_port *port)
struct tty_bufhead *buf = &port->buf;
struct tty_buffer *p, *next;
struct llist_node *llist;
+ int zero = 0;
while ((p = buf->head) != NULL) {
buf->head = p->next;
+ atomic_sub(p->size, &buf->memory_used);
if (p->size > 0)
kfree(p);
}
llist = llist_del_all(&buf->free);
- llist_for_each_entry_safe(p, next, llist, free)
+ llist_for_each_entry_safe(p, next, llist, free) {
+ atomic_sub(p->size, &buf->memory_used);
kfree(p);
+ }
+
tty_buffer_reset(&buf->sentinel, 0);
buf->head = &buf->sentinel;
buf->tail = &buf->sentinel;
- atomic_set(&buf->memory_used, 0);
+ atomic_xchg(&buf->memory_used, zero);
+ WARN_ON(zero != 0);
}
/**
--
1.8.4.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 1/1] TTY: tty_buffer, warn on leaks
2013-11-11 20:05 [PATCH 1/1] TTY: tty_buffer, warn on leaks Jiri Slaby
@ 2013-11-11 23:13 ` Peter Hurley
2013-11-27 1:13 ` Peter Hurley
0 siblings, 1 reply; 3+ messages in thread
From: Peter Hurley @ 2013-11-11 23:13 UTC (permalink / raw)
To: Jiri Slaby, gregkh; +Cc: jirislaby, linux-kernel
On 11/11/2013 03:05 PM, Jiri Slaby wrote:
> When we leak something, warn about that. For that we need to account
> the memory used also in the free_all method. It is handled elsewhere
> correctly.
Hi Jiri,
Good idea.
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> ---
> drivers/tty/tty_buffer.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
> index 5f08c39e76ab..20cb9492dbf8 100644
> --- a/drivers/tty/tty_buffer.c
> +++ b/drivers/tty/tty_buffer.c
> @@ -115,21 +115,27 @@ void tty_buffer_free_all(struct tty_port *port)
> struct tty_bufhead *buf = &port->buf;
> struct tty_buffer *p, *next;
> struct llist_node *llist;
> + int zero = 0;
>
> while ((p = buf->head) != NULL) {
> buf->head = p->next;
> + atomic_sub(p->size, &buf->memory_used);
buf->memory_used doesn't need to be treated atomically here,
and doing so implies that it's necessary.
Accumulating p->size in a non-atomic local is probably better.
> if (p->size > 0)
> kfree(p);
> }
> llist = llist_del_all(&buf->free);
> - llist_for_each_entry_safe(p, next, llist, free)
> + llist_for_each_entry_safe(p, next, llist, free) {
> + atomic_sub(p->size, &buf->memory_used);
Same here.
> kfree(p);
> + }
> +
>
> tty_buffer_reset(&buf->sentinel, 0);
> buf->head = &buf->sentinel;
> buf->tail = &buf->sentinel;
>
> - atomic_set(&buf->memory_used, 0);
> + atomic_xchg(&buf->memory_used, zero);
> + WARN_ON(zero != 0);
Then,
WARN_ON(atomic_read(&buf->memory_used) != <local accum>);
atomic_set(&buf->memory_used, 0);
?
Regards,
Peter Hurley
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 1/1] TTY: tty_buffer, warn on leaks
2013-11-11 23:13 ` Peter Hurley
@ 2013-11-27 1:13 ` Peter Hurley
0 siblings, 0 replies; 3+ messages in thread
From: Peter Hurley @ 2013-11-27 1:13 UTC (permalink / raw)
To: Jiri Slaby, gregkh; +Cc: jirislaby, linux-kernel
On 11/11/2013 06:13 PM, Peter Hurley wrote:
> On 11/11/2013 03:05 PM, Jiri Slaby wrote:
>> When we leak something, warn about that. For that we need to account
>> the memory used also in the free_all method. It is handled elsewhere
>> correctly.
>
> Hi Jiri,
>
> Good idea.
>
>> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
>> ---
>> drivers/tty/tty_buffer.c | 10 ++++++++--
>> 1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
>> index 5f08c39e76ab..20cb9492dbf8 100644
>> --- a/drivers/tty/tty_buffer.c
>> +++ b/drivers/tty/tty_buffer.c
>> @@ -115,21 +115,27 @@ void tty_buffer_free_all(struct tty_port *port)
>> struct tty_bufhead *buf = &port->buf;
>> struct tty_buffer *p, *next;
>> struct llist_node *llist;
>> + int zero = 0;
>>
>> while ((p = buf->head) != NULL) {
>> buf->head = p->next;
>> + atomic_sub(p->size, &buf->memory_used);
>
> buf->memory_used doesn't need to be treated atomically here,
> and doing so implies that it's necessary.
>
> Accumulating p->size in a non-atomic local is probably better.
>
>> if (p->size > 0)
>> kfree(p);
>> }
>> llist = llist_del_all(&buf->free);
>> - llist_for_each_entry_safe(p, next, llist, free)
>> + llist_for_each_entry_safe(p, next, llist, free) {
>> + atomic_sub(p->size, &buf->memory_used);
>
> Same here.
Sorry, I forgot: the buffers on the free list have already been
accounted for in tty_buffer_free() so don't form part of the
buf->mem_used total.
The buffer memory accounting was like that in 3.7 so I left it in.
static void tty_buffer_free(struct tty_port *port, struct tty_buffer *b)
{
struct tty_bufhead *buf = &port->buf;
/* Dumb strategy for now - should keep some stats */
WARN_ON(atomic_sub_return(b->size, &buf->mem_used) < 0);
if (b->size > MIN_TTYB_SIZE)
kfree(b);
else if (b->size > 0)
llist_add(&b->free, &buf->free);
}
Regards,
Peter Hurley
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-11-11 23:13 ` Peter Hurley
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