* Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
2016-05-16 16:53 ` [dpdk-dev] [PATCH v2] " Hiroyuki Mikita
@ 2016-05-17 10:58 ` Bruce Richardson
2016-05-17 11:06 ` Ananyev, Konstantin
` (2 subsequent siblings)
3 siblings, 0 replies; 23+ messages in thread
From: Bruce Richardson @ 2016-05-17 10:58 UTC (permalink / raw)
To: Hiroyuki Mikita; +Cc: olivier.matz, dev
On Tue, May 17, 2016 at 01:53:20AM +0900, Hiroyuki Mikita wrote:
> The rte_pktmbuf_detach() function should decrease refcnt on a direct
> buffer.
>
> Signed-off-by: Hiroyuki Mikita <h.mikita89@gmail.com>
> ---
> v2:
> * introduced a new function rte_pktmbuf_detach2() which decrease refcnt.
> * marked rte_pktmbuf_detach() as deprecated.
> * added comments about refcnt to rte_pktmbuf_attach() and rte_pktmbuf_detach().
> * checked refcnt when detaching in unit tests.
> * added this issue to release notes.
>
Rather than detach2, would unattach be better?
/Bruce
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
2016-05-16 16:53 ` [dpdk-dev] [PATCH v2] " Hiroyuki Mikita
2016-05-17 10:58 ` Bruce Richardson
@ 2016-05-17 11:06 ` Ananyev, Konstantin
2016-05-17 12:43 ` Thomas Monjalon
2016-05-17 16:35 ` [dpdk-dev] [PATCH v3] " Hiroyuki Mikita
3 siblings, 0 replies; 23+ messages in thread
From: Ananyev, Konstantin @ 2016-05-17 11:06 UTC (permalink / raw)
To: Hiroyuki Mikita, olivier.matz; +Cc: dev
Hi Hiroyuki,
>
> The rte_pktmbuf_detach() function should decrease refcnt on a direct
> buffer.
>
> Signed-off-by: Hiroyuki Mikita <h.mikita89@gmail.com>
> ---
> v2:
> * introduced a new function rte_pktmbuf_detach2() which decrease refcnt.
> * marked rte_pktmbuf_detach() as deprecated.
> * added comments about refcnt to rte_pktmbuf_attach() and rte_pktmbuf_detach().
> * checked refcnt when detaching in unit tests.
> * added this issue to release notes.
>
> app/test/test_mbuf.c | 9 +++++--
> doc/guides/rel_notes/release_16_07.rst | 11 ++++-----
> lib/librte_mbuf/rte_mbuf.h | 43 +++++++++++++++++++++++++++++++---
> 3 files changed, 51 insertions(+), 12 deletions(-)
>
> diff --git a/app/test/test_mbuf.c b/app/test/test_mbuf.c
> index 98ff93a..2bf05eb 100644
> --- a/app/test/test_mbuf.c
> +++ b/app/test/test_mbuf.c
> @@ -438,6 +438,7 @@ test_attach_from_different_pool(void)
> struct rte_mbuf *clone = NULL;
> struct rte_mbuf *clone2 = NULL;
> char *data, *c_data, *c_data2;
> + uint16_t refcnt;
>
> /* alloc a mbuf */
> m = rte_pktmbuf_alloc(pktmbuf_pool);
> @@ -508,13 +509,17 @@ test_attach_from_different_pool(void)
> GOTO_FAIL("invalid refcnt in m\n");
>
> /* detach the clones */
> - rte_pktmbuf_detach(clone);
> + refcnt = rte_pktmbuf_detach2(clone);
> if (c_data != rte_pktmbuf_mtod(clone, char *))
> GOTO_FAIL("clone was not detached properly\n");
> + if (refcnt != 2 || rte_mbuf_refcnt_read(m) != 2)
> + GOTO_FAIL("invalid refcnt in m\n");
>
> - rte_pktmbuf_detach(clone2);
> + refcnt = rte_pktmbuf_detach2(clone2);
> if (c_data2 != rte_pktmbuf_mtod(clone2, char *))
> GOTO_FAIL("clone2 was not detached properly\n");
> + if (refcnt != 1 || rte_mbuf_refcnt_read(m) != 1)
> + GOTO_FAIL("invalid refcnt in m\n");
>
> /* free the clones and the initial mbuf */
> rte_pktmbuf_free(clone2);
> diff --git a/doc/guides/rel_notes/release_16_07.rst b/doc/guides/rel_notes/release_16_07.rst
> index f6d543c..9678c1f 100644
> --- a/doc/guides/rel_notes/release_16_07.rst
> +++ b/doc/guides/rel_notes/release_16_07.rst
> @@ -77,13 +77,10 @@ Other
> Known Issues
> ------------
>
> -This section should contain new known issues in this release. Sample format:
> -
> -* **Add title in present tense with full stop.**
> -
> - Add a short 1-2 sentence description of the known issue in the present
> - tense. Add information on any known workarounds.
> -
> +* The ``rte_pktmbuf_detach()`` function does not decrement the direct
> + mbuf's reference counter. It leads a memory leak of the direct
> + mbuf. The workaround is to explicitly decrement the reference
> + counter or use ``rte_pktmbuf_detach2()``.
>
> API Changes
> -----------
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 529debb..c0a592d 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -1408,6 +1408,7 @@ static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool,
> *
> * After attachment we refer the mbuf we attached as 'indirect',
> * while mbuf we attached to as 'direct'.
> + * The direct mbuf's reference counter is incremented.
> * Right now, not supported:
> * - attachment for already indirect mbuf (e.g. - mi has to be direct).
> * - mbuf we trying to attach (mi) is used by someone else
> @@ -1459,15 +1460,50 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m)
> /**
> * Detach an indirect packet mbuf.
> *
> + * Note: It is deprecated.
> + * The direct mbuf's reference counter is not decremented.
> + *
> + * - restore original mbuf address and length values.
> + * - reset pktmbuf data and data_len to their default values.
> + * All other fields of the given packet mbuf will be left intact.
> + *
> + * @param m
> + * The indirect attached packet mbuf.
> + */
> +static inline void __rte_deprecated rte_pktmbuf_detach(struct rte_mbuf *m)
> +{
> + struct rte_mempool *mp = m->pool;
> + uint32_t mbuf_size, buf_len, priv_size;
> +
> + priv_size = rte_pktmbuf_priv_size(mp);
> + mbuf_size = sizeof(struct rte_mbuf) + priv_size;
> + buf_len = rte_pktmbuf_data_room_size(mp);
> +
> + m->priv_size = priv_size;
> + m->buf_addr = (char *)m + mbuf_size;
> + m->buf_physaddr = rte_mempool_virt2phy(mp, m) + mbuf_size;
> + m->buf_len = (uint16_t)buf_len;
> + m->data_off = RTE_MIN(RTE_PKTMBUF_HEADROOM, (uint16_t)m->buf_len);
> + m->data_len = 0;
> + m->ol_flags = 0;
> +}
I still think it would be good to have a separate function for what rte_pktmbuf_detach()
Is doing right now: restore original values of indirect mbuf.
Probably rename it to rte_pktmbuf_restore() or so and make _detach2() (unatach() ?)
to call it internally.
> +
> +/**
> + * Detach an indirect packet mbuf.
> + *
> * - restore original mbuf address and length values.
> * - reset pktmbuf data and data_len to their default values.
> * All other fields of the given packet mbuf will be left intact.
> + * - decrement the direct mbuf's reference counter.
> *
> * @param m
> * The indirect attached packet mbuf.
> + * @return
> + * The updated value of the direct mbuf's reference counter.
> */
> -static inline void rte_pktmbuf_detach(struct rte_mbuf *m)
> +static inline uint16_t rte_pktmbuf_detach2(struct rte_mbuf *m)
> {
> + struct rte_mbuf *md = rte_mbuf_from_indirect(m);
> struct rte_mempool *mp = m->pool;
> uint32_t mbuf_size, buf_len, priv_size;
>
> @@ -1482,6 +1518,8 @@ static inline void rte_pktmbuf_detach(struct rte_mbuf *m)
> m->data_off = RTE_MIN(RTE_PKTMBUF_HEADROOM, (uint16_t)m->buf_len);
> m->data_len = 0;
> m->ol_flags = 0;
> +
> + return rte_mbuf_refcnt_update(md, -1);
> }
>
> static inline struct rte_mbuf* __attribute__((always_inline))
> @@ -1497,8 +1535,7 @@ __rte_pktmbuf_prefree_seg(struct rte_mbuf *m)
> */
> if (RTE_MBUF_INDIRECT(m)) {
> struct rte_mbuf *md = rte_mbuf_from_indirect(m);
I don't think there is a need to invoke rte_mbuf_from_indirect() twice.
You can either pass md as a second parameter to _detach2(),
or make detach2() to invoke __rte_mbuf_raw_free()
if rte_mbuf_refcnt_update(md, -1) == 0.
Konstantin
> - rte_pktmbuf_detach(m);
> - if (rte_mbuf_refcnt_update(md, -1) == 0)
> + if (rte_pktmbuf_detach2(m) == 0)
> __rte_mbuf_raw_free(md);
> }
> return m;
> --
> 1.9.1
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
2016-05-16 16:53 ` [dpdk-dev] [PATCH v2] " Hiroyuki Mikita
2016-05-17 10:58 ` Bruce Richardson
2016-05-17 11:06 ` Ananyev, Konstantin
@ 2016-05-17 12:43 ` Thomas Monjalon
2016-05-17 12:59 ` Ananyev, Konstantin
2016-05-17 16:35 ` [dpdk-dev] [PATCH v3] " Hiroyuki Mikita
3 siblings, 1 reply; 23+ messages in thread
From: Thomas Monjalon @ 2016-05-17 12:43 UTC (permalink / raw)
To: Hiroyuki Mikita, konstantin.ananyev; +Cc: dev, olivier.matz
2016-05-17 01:53, Hiroyuki Mikita:
> The rte_pktmbuf_detach() function should decrease refcnt on a direct
> buffer.
>
> Signed-off-by: Hiroyuki Mikita <h.mikita89@gmail.com>
> ---
> v2:
> * introduced a new function rte_pktmbuf_detach2() which decrease refcnt.
As you have noticed, "whenever the indirect buffer is detached,
the reference counter on the direct buffer is decremented."
So the current behaviour of rte_pktmbuf_detach() is buggy.
Why not fix it without renaming?
If you consider this behavioral bug is part of the API, we
can fix it in a new function unattach and deprecate detach.
But Konstantin, why do you want to keep a restore function?
What is the need?
Please explicit the function name for the detach operation in
doc/guides/prog_guide/mbuf_lib.rst (whatever detach2 or unattach).
> * marked rte_pktmbuf_detach() as deprecated.
> * added comments about refcnt to rte_pktmbuf_attach() and rte_pktmbuf_detach().
> * checked refcnt when detaching in unit tests.
> * added this issue to release notes.
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
2016-05-17 12:43 ` Thomas Monjalon
@ 2016-05-17 12:59 ` Ananyev, Konstantin
2016-05-17 13:39 ` Thomas Monjalon
0 siblings, 1 reply; 23+ messages in thread
From: Ananyev, Konstantin @ 2016-05-17 12:59 UTC (permalink / raw)
To: Thomas Monjalon, Hiroyuki Mikita; +Cc: dev, olivier.matz
Hi Thomas,
> > The rte_pktmbuf_detach() function should decrease refcnt on a direct
> > buffer.
> >
> > Signed-off-by: Hiroyuki Mikita <h.mikita89@gmail.com>
> > ---
> > v2:
> > * introduced a new function rte_pktmbuf_detach2() which decrease refcnt.
>
> As you have noticed, "whenever the indirect buffer is detached,
> the reference counter on the direct buffer is decremented."
> So the current behaviour of rte_pktmbuf_detach() is buggy.
> Why not fix it without renaming?
> If you consider this behavioral bug is part of the API, we
> can fix it in a new function unattach and deprecate detach.
> But Konstantin, why do you want to keep a restore function?
> What is the need?
I think it might be a useful functionality in some situations:
some users can attach/detach to external memory buffers (no mbufs)
and similar functionality is required.
Let say right now examples/vhost/main.c has its own pktmbuf_detach_zcp()
which is doing pretty much the same - restore original values, after detaching
mbuf from external (virtio) memory buffer.
Would be good if we'll use a standard API function here.
Konstantin
>
> Please explicit the function name for the detach operation in
> doc/guides/prog_guide/mbuf_lib.rst (whatever detach2 or unattach).
>
> > * marked rte_pktmbuf_detach() as deprecated.
> > * added comments about refcnt to rte_pktmbuf_attach() and rte_pktmbuf_detach().
> > * checked refcnt when detaching in unit tests.
> > * added this issue to release notes.
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
2016-05-17 12:59 ` Ananyev, Konstantin
@ 2016-05-17 13:39 ` Thomas Monjalon
2016-05-17 13:44 ` Ananyev, Konstantin
0 siblings, 1 reply; 23+ messages in thread
From: Thomas Monjalon @ 2016-05-17 13:39 UTC (permalink / raw)
To: Ananyev, Konstantin; +Cc: dev, Hiroyuki Mikita, olivier.matz
2016-05-17 12:59, Ananyev, Konstantin:
> > > The rte_pktmbuf_detach() function should decrease refcnt on a direct
> > > buffer.
> >
> > As you have noticed, "whenever the indirect buffer is detached,
> > the reference counter on the direct buffer is decremented."
> > So the current behaviour of rte_pktmbuf_detach() is buggy.
> > Why not fix it without renaming?
> > If you consider this behavioral bug is part of the API, we
> > can fix it in a new function unattach and deprecate detach.
> > But Konstantin, why do you want to keep a restore function?
> > What is the need?
>
> I think it might be a useful functionality in some situations:
> some users can attach/detach to external memory buffers (no mbufs)
> and similar functionality is required.
Attach to external memory buffer (raw buffer) is not currently supported.
> Let say right now examples/vhost/main.c has its own pktmbuf_detach_zcp()
You should look at the commit http://dpdk.org/commit/68363d85
"examples/vhost: remove the non-working zero copy code"
> which is doing pretty much the same - restore original values, after detaching
> mbuf from external (virtio) memory buffer.
> Would be good if we'll use a standard API function here.
You are welcome to implement mbuf attach to raw buffer.
But it is not a requirement for this fix.
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
2016-05-17 13:39 ` Thomas Monjalon
@ 2016-05-17 13:44 ` Ananyev, Konstantin
2016-05-17 14:19 ` Thomas Monjalon
0 siblings, 1 reply; 23+ messages in thread
From: Ananyev, Konstantin @ 2016-05-17 13:44 UTC (permalink / raw)
To: Thomas Monjalon; +Cc: dev, Hiroyuki Mikita, olivier.matz
> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> Sent: Tuesday, May 17, 2016 2:40 PM
> To: Ananyev, Konstantin
> Cc: dev@dpdk.org; Hiroyuki Mikita; olivier.matz@6wind.com
> Subject: Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
>
> 2016-05-17 12:59, Ananyev, Konstantin:
> > > > The rte_pktmbuf_detach() function should decrease refcnt on a direct
> > > > buffer.
> > >
> > > As you have noticed, "whenever the indirect buffer is detached,
> > > the reference counter on the direct buffer is decremented."
> > > So the current behaviour of rte_pktmbuf_detach() is buggy.
> > > Why not fix it without renaming?
> > > If you consider this behavioral bug is part of the API, we
> > > can fix it in a new function unattach and deprecate detach.
> > > But Konstantin, why do you want to keep a restore function?
> > > What is the need?
> >
> > I think it might be a useful functionality in some situations:
> > some users can attach/detach to external memory buffers (no mbufs)
> > and similar functionality is required.
>
> Attach to external memory buffer (raw buffer) is not currently supported.
>
> > Let say right now examples/vhost/main.c has its own pktmbuf_detach_zcp()
>
> You should look at the commit http://dpdk.org/commit/68363d85
> "examples/vhost: remove the non-working zero copy code"
>
> > which is doing pretty much the same - restore original values, after detaching
> > mbuf from external (virtio) memory buffer.
> > Would be good if we'll use a standard API function here.
>
> You are welcome to implement mbuf attach to raw buffer.
> But it is not a requirement for this fix.
Hmm, still not sure why we can't keep an existing function?
Obviously it wouldn't cost anything and I still think might be useful.
Konstantin
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
2016-05-17 13:44 ` Ananyev, Konstantin
@ 2016-05-17 14:19 ` Thomas Monjalon
2016-05-17 15:45 ` Ananyev, Konstantin
0 siblings, 1 reply; 23+ messages in thread
From: Thomas Monjalon @ 2016-05-17 14:19 UTC (permalink / raw)
To: Ananyev, Konstantin; +Cc: dev, Hiroyuki Mikita, olivier.matz
2016-05-17 13:44, Ananyev, Konstantin:
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > 2016-05-17 12:59, Ananyev, Konstantin:
> > > > > The rte_pktmbuf_detach() function should decrease refcnt on a direct
> > > > > buffer.
> > > >
> > > > As you have noticed, "whenever the indirect buffer is detached,
> > > > the reference counter on the direct buffer is decremented."
> > > > So the current behaviour of rte_pktmbuf_detach() is buggy.
> > > > Why not fix it without renaming?
> > > > If you consider this behavioral bug is part of the API, we
> > > > can fix it in a new function unattach and deprecate detach.
> > > > But Konstantin, why do you want to keep a restore function?
> > > > What is the need?
> > >
> > > I think it might be a useful functionality in some situations:
> > > some users can attach/detach to external memory buffers (no mbufs)
> > > and similar functionality is required.
> >
> > Attach to external memory buffer (raw buffer) is not currently supported.
> >
> > > Let say right now examples/vhost/main.c has its own pktmbuf_detach_zcp()
> >
> > You should look at the commit http://dpdk.org/commit/68363d85
> > "examples/vhost: remove the non-working zero copy code"
> >
> > > which is doing pretty much the same - restore original values, after detaching
> > > mbuf from external (virtio) memory buffer.
> > > Would be good if we'll use a standard API function here.
> >
> > You are welcome to implement mbuf attach to raw buffer.
> > But it is not a requirement for this fix.
>
> Hmm, still not sure why we can't keep an existing function?
Because it does not do what its name (and doc) suggest.
> Obviously it wouldn't cost anything and I still think might be useful.
It costs to overcomplicate API for only a half support.
If you need the feature "attach to raw", please implement it completely.
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
2016-05-17 14:19 ` Thomas Monjalon
@ 2016-05-17 15:45 ` Ananyev, Konstantin
2016-05-17 16:12 ` Hiroyuki MIKITA
0 siblings, 1 reply; 23+ messages in thread
From: Ananyev, Konstantin @ 2016-05-17 15:45 UTC (permalink / raw)
To: Thomas Monjalon; +Cc: dev, Hiroyuki Mikita, olivier.matz
> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> Sent: Tuesday, May 17, 2016 3:19 PM
> To: Ananyev, Konstantin
> Cc: dev@dpdk.org; Hiroyuki Mikita; olivier.matz@6wind.com
> Subject: Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
>
> 2016-05-17 13:44, Ananyev, Konstantin:
> > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > > 2016-05-17 12:59, Ananyev, Konstantin:
> > > > > > The rte_pktmbuf_detach() function should decrease refcnt on a direct
> > > > > > buffer.
> > > > >
> > > > > As you have noticed, "whenever the indirect buffer is detached,
> > > > > the reference counter on the direct buffer is decremented."
> > > > > So the current behaviour of rte_pktmbuf_detach() is buggy.
> > > > > Why not fix it without renaming?
> > > > > If you consider this behavioral bug is part of the API, we
> > > > > can fix it in a new function unattach and deprecate detach.
> > > > > But Konstantin, why do you want to keep a restore function?
> > > > > What is the need?
> > > >
> > > > I think it might be a useful functionality in some situations:
> > > > some users can attach/detach to external memory buffers (no mbufs)
> > > > and similar functionality is required.
> > >
> > > Attach to external memory buffer (raw buffer) is not currently supported.
> > >
> > > > Let say right now examples/vhost/main.c has its own pktmbuf_detach_zcp()
> > >
> > > You should look at the commit http://dpdk.org/commit/68363d85
> > > "examples/vhost: remove the non-working zero copy code"
> > >
> > > > which is doing pretty much the same - restore original values, after detaching
> > > > mbuf from external (virtio) memory buffer.
> > > > Would be good if we'll use a standard API function here.
> > >
> > > You are welcome to implement mbuf attach to raw buffer.
> > > But it is not a requirement for this fix.
> >
> > Hmm, still not sure why we can't keep an existing function?
>
> Because it does not do what its name (and doc) suggest.
>
> > Obviously it wouldn't cost anything and I still think might be useful.
>
> It costs to overcomplicate API for only a half support.
I still think it is better to have it then not, but wouldn't insist here.
Konstantin
> If you need the feature "attach to raw", please implement it completely.
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
2016-05-17 15:45 ` Ananyev, Konstantin
@ 2016-05-17 16:12 ` Hiroyuki MIKITA
0 siblings, 0 replies; 23+ messages in thread
From: Hiroyuki MIKITA @ 2016-05-17 16:12 UTC (permalink / raw)
To: Ananyev, Konstantin; +Cc: Thomas Monjalon, dev, olivier.matz
I think this behavior is not part of the API, it is a bug.
I agree that detach() frees the direct mbuf when refcnt becomes 0,
Konstantin suggests.
It is a right behavior of reference counting.
Regards,
Hiroyuki
2016-05-18 0:45 GMT+09:00 Ananyev, Konstantin <konstantin.ananyev@intel.com>:
>
>
>> -----Original Message-----
>> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
>> Sent: Tuesday, May 17, 2016 3:19 PM
>> To: Ananyev, Konstantin
>> Cc: dev@dpdk.org; Hiroyuki Mikita; olivier.matz@6wind.com
>> Subject: Re: [dpdk-dev] [PATCH v2] mbuf: decrease refcnt when detaching
>>
>> 2016-05-17 13:44, Ananyev, Konstantin:
>> > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
>> > > 2016-05-17 12:59, Ananyev, Konstantin:
>> > > > > > The rte_pktmbuf_detach() function should decrease refcnt on a direct
>> > > > > > buffer.
>> > > > >
>> > > > > As you have noticed, "whenever the indirect buffer is detached,
>> > > > > the reference counter on the direct buffer is decremented."
>> > > > > So the current behaviour of rte_pktmbuf_detach() is buggy.
>> > > > > Why not fix it without renaming?
>> > > > > If you consider this behavioral bug is part of the API, we
>> > > > > can fix it in a new function unattach and deprecate detach.
>> > > > > But Konstantin, why do you want to keep a restore function?
>> > > > > What is the need?
>> > > >
>> > > > I think it might be a useful functionality in some situations:
>> > > > some users can attach/detach to external memory buffers (no mbufs)
>> > > > and similar functionality is required.
>> > >
>> > > Attach to external memory buffer (raw buffer) is not currently supported.
>> > >
>> > > > Let say right now examples/vhost/main.c has its own pktmbuf_detach_zcp()
>> > >
>> > > You should look at the commit http://dpdk.org/commit/68363d85
>> > > "examples/vhost: remove the non-working zero copy code"
>> > >
>> > > > which is doing pretty much the same - restore original values, after detaching
>> > > > mbuf from external (virtio) memory buffer.
>> > > > Would be good if we'll use a standard API function here.
>> > >
>> > > You are welcome to implement mbuf attach to raw buffer.
>> > > But it is not a requirement for this fix.
>> >
>> > Hmm, still not sure why we can't keep an existing function?
>>
>> Because it does not do what its name (and doc) suggest.
>>
>> > Obviously it wouldn't cost anything and I still think might be useful.
>>
>> It costs to overcomplicate API for only a half support.
>
> I still think it is better to have it then not, but wouldn't insist here.
> Konstantin
>
>> If you need the feature "attach to raw", please implement it completely.
>
^ permalink raw reply [flat|nested] 23+ messages in thread
* [dpdk-dev] [PATCH v3] mbuf: decrease refcnt when detaching
2016-05-16 16:53 ` [dpdk-dev] [PATCH v2] " Hiroyuki Mikita
` (2 preceding siblings ...)
2016-05-17 12:43 ` Thomas Monjalon
@ 2016-05-17 16:35 ` Hiroyuki Mikita
2016-05-18 11:58 ` Olivier Matz
2016-05-18 14:41 ` [dpdk-dev] [PATCH v4] " Hiroyuki Mikita
3 siblings, 2 replies; 23+ messages in thread
From: Hiroyuki Mikita @ 2016-05-17 16:35 UTC (permalink / raw)
To: olivier.matz, thomas.monjalon, konstantin.ananyev; +Cc: dev
The rte_pktmbuf_detach() function should decrease refcnt on a direct
buffer.
Signed-off-by: Hiroyuki Mikita <h.mikita89@gmail.com>
---
v3:
* fixed rte_pktmbuf_detach() to decrease refcnt.
* free the direct mbuf when refcnt becomes 0.
* added this issue to Resolved Issues in release notes.
v2:
* introduced a new function rte_pktmbuf_detach2() which decrease refcnt.
* marked rte_pktmbuf_detach() as deprecated.
* added comments about refcnt to rte_pktmbuf_attach() and rte_pktmbuf_detach().
* checked refcnt when detaching in unit tests.
* added this issue to release notes.
app/test/test_mbuf.c | 4 ++++
doc/guides/rel_notes/release_16_07.rst | 6 ++++++
lib/librte_mbuf/rte_mbuf.h | 17 ++++++++++-------
3 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/app/test/test_mbuf.c b/app/test/test_mbuf.c
index 98ff93a..8460db7 100644
--- a/app/test/test_mbuf.c
+++ b/app/test/test_mbuf.c
@@ -511,10 +511,14 @@ test_attach_from_different_pool(void)
rte_pktmbuf_detach(clone);
if (c_data != rte_pktmbuf_mtod(clone, char *))
GOTO_FAIL("clone was not detached properly\n");
+ if (rte_mbuf_refcnt_read(m) != 2)
+ GOTO_FAIL("invalid refcnt in m\n");
rte_pktmbuf_detach(clone2);
if (c_data2 != rte_pktmbuf_mtod(clone2, char *))
GOTO_FAIL("clone2 was not detached properly\n");
+ if (rte_mbuf_refcnt_read(m) != 1)
+ GOTO_FAIL("invalid refcnt in m\n");
/* free the clones and the initial mbuf */
rte_pktmbuf_free(clone2);
diff --git a/doc/guides/rel_notes/release_16_07.rst b/doc/guides/rel_notes/release_16_07.rst
index f6d543c..8283373 100644
--- a/doc/guides/rel_notes/release_16_07.rst
+++ b/doc/guides/rel_notes/release_16_07.rst
@@ -65,6 +65,12 @@ Drivers
Libraries
~~~~~~~~~
+* **mbuf: Fixed refcnt update when detaching.**
+
+ Fix the ``rte_pktmbuf_detach()`` function to decrement the direct
+ mbuf's reference counter. The previous behavior was not to affect
+ the reference counter. It lead a memory leak of the direct mbuf.
+
Examples
~~~~~~~~
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 529debb..299b60e 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -1408,6 +1408,8 @@ static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool,
*
* After attachment we refer the mbuf we attached as 'indirect',
* while mbuf we attached to as 'direct'.
+ * The direct mbuf's reference counter is incremented.
+ *
* Right now, not supported:
* - attachment for already indirect mbuf (e.g. - mi has to be direct).
* - mbuf we trying to attach (mi) is used by someone else
@@ -1462,12 +1464,15 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m)
* - restore original mbuf address and length values.
* - reset pktmbuf data and data_len to their default values.
* All other fields of the given packet mbuf will be left intact.
+ * - decrement the direct mbuf's reference counter.
+ * When the reference counter becomes 0, the direct mbuf is freed.
*
* @param m
* The indirect attached packet mbuf.
*/
static inline void rte_pktmbuf_detach(struct rte_mbuf *m)
{
+ struct rte_mbuf *md = rte_mbuf_from_indirect(m);
struct rte_mempool *mp = m->pool;
uint32_t mbuf_size, buf_len, priv_size;
@@ -1482,6 +1487,10 @@ static inline void rte_pktmbuf_detach(struct rte_mbuf *m)
m->data_off = RTE_MIN(RTE_PKTMBUF_HEADROOM, (uint16_t)m->buf_len);
m->data_len = 0;
m->ol_flags = 0;
+
+ if (rte_mbuf_refcnt_update(md, -1) == 0) {
+ __rte_mbuf_raw_free(md);
+ }
}
static inline struct rte_mbuf* __attribute__((always_inline))
@@ -1491,15 +1500,9 @@ __rte_pktmbuf_prefree_seg(struct rte_mbuf *m)
if (likely(rte_mbuf_refcnt_update(m, -1) == 0)) {
- /* if this is an indirect mbuf, then
- * - detach mbuf
- * - free attached mbuf segment
- */
+ /* if this is an indirect mbuf, it is detached. */
if (RTE_MBUF_INDIRECT(m)) {
- struct rte_mbuf *md = rte_mbuf_from_indirect(m);
rte_pktmbuf_detach(m);
- if (rte_mbuf_refcnt_update(md, -1) == 0)
- __rte_mbuf_raw_free(md);
}
return m;
}
--
1.9.1
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [dpdk-dev] [PATCH v3] mbuf: decrease refcnt when detaching
2016-05-17 16:35 ` [dpdk-dev] [PATCH v3] " Hiroyuki Mikita
@ 2016-05-18 11:58 ` Olivier Matz
2016-05-18 14:29 ` Hiroyuki Mikita
2016-05-18 14:41 ` [dpdk-dev] [PATCH v4] " Hiroyuki Mikita
1 sibling, 1 reply; 23+ messages in thread
From: Olivier Matz @ 2016-05-18 11:58 UTC (permalink / raw)
To: Hiroyuki Mikita, thomas.monjalon, konstantin.ananyev; +Cc: dev
Hi Hiroyuki,
Thanks for submitting a new version.
There are some styling issues in the patch, I highlighted them below
but you can check them by using checkpatch:
DPDK_CHECKPATCH_PATH=/path/to/linux/checkpatch.pl \
scripts/checkpatches.sh file.patch
On 05/17/2016 06:35 PM, Hiroyuki Mikita wrote:
> The rte_pktmbuf_detach() function should decrease refcnt on a direct
> buffer.
>
> Signed-off-by: Hiroyuki Mikita <h.mikita89@gmail.com>
>
> [...]
>
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 529debb..299b60e 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -1408,6 +1408,8 @@ static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool,
> *
> * After attachment we refer the mbuf we attached as 'indirect',
> * while mbuf we attached to as 'direct'.
> + * The direct mbuf's reference counter is incremented.
> + *
ERROR:TRAILING_WHITESPACE: trailing whitespace
#82: FILE: lib/librte_mbuf/rte_mbuf.h:1412:
+ * $
> * Right now, not supported:
> * - attachment for already indirect mbuf (e.g. - mi has to be direct).
> * - mbuf we trying to attach (mi) is used by someone else
> @@ -1462,12 +1464,15 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m)
> * - restore original mbuf address and length values.
> * - reset pktmbuf data and data_len to their default values.
> * All other fields of the given packet mbuf will be left intact.
> + * - decrement the direct mbuf's reference counter.
> + * When the reference counter becomes 0, the direct mbuf is freed.
Minor comment here: I think something like that would be clearer:
* - restore original mbuf address and length values.
* - reset pktmbuf data and data_len to their default values.
* - decrement the direct mbuf's reference counter. When the
* reference counter becomes 0, the direct mbuf is freed.
*
* All other fields of the given packet mbuf will be left intact.
> *
> * @param m
> * The indirect attached packet mbuf.
> */
> static inline void rte_pktmbuf_detach(struct rte_mbuf *m)
> {
> + struct rte_mbuf *md = rte_mbuf_from_indirect(m);
> struct rte_mempool *mp = m->pool;
> uint32_t mbuf_size, buf_len, priv_size;
>
> @@ -1482,6 +1487,10 @@ static inline void rte_pktmbuf_detach(struct rte_mbuf *m)
> m->data_off = RTE_MIN(RTE_PKTMBUF_HEADROOM, (uint16_t)m->buf_len);
> m->data_len = 0;
> m->ol_flags = 0;
> +
> + if (rte_mbuf_refcnt_update(md, -1) == 0) {
> + __rte_mbuf_raw_free(md);
> + }
> }
WARNING:BRACES: braces {} are not necessary for single statement blocks
#107: FILE: lib/librte_mbuf/rte_mbuf.h:1491:
+ if (rte_mbuf_refcnt_update(md, -1) == 0) {
+ __rte_mbuf_raw_free(md);
+ }
>
> static inline struct rte_mbuf* __attribute__((always_inline))
> @@ -1491,15 +1500,9 @@ __rte_pktmbuf_prefree_seg(struct rte_mbuf *m)
>
> if (likely(rte_mbuf_refcnt_update(m, -1) == 0)) {
>
> - /* if this is an indirect mbuf, then
> - * - detach mbuf
> - * - free attached mbuf segment
> - */
> + /* if this is an indirect mbuf, it is detached. */
> if (RTE_MBUF_INDIRECT(m)) {
> - struct rte_mbuf *md = rte_mbuf_from_indirect(m);
> rte_pktmbuf_detach(m);
> - if (rte_mbuf_refcnt_update(md, -1) == 0)
> - __rte_mbuf_raw_free(md);
> }
> return m;
> }
>
It's not seen by checkpatch, but the braces could also be removed
here.
Apart from this, it looks good to me. I'm ok with not providing a
compat function as we could consider it was a bug.
Thanks for working on this.
Olivier
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [dpdk-dev] [PATCH v3] mbuf: decrease refcnt when detaching
2016-05-18 11:58 ` Olivier Matz
@ 2016-05-18 14:29 ` Hiroyuki Mikita
0 siblings, 0 replies; 23+ messages in thread
From: Hiroyuki Mikita @ 2016-05-18 14:29 UTC (permalink / raw)
To: Olivier Matz; +Cc: Thomas Monjalon, Ananyev, Konstantin, dev
Hi Olivier,
Thanks for reviewing.
I am fixing the patch to follow your comments.
Regards,
Hiroyuki
2016-05-18 20:58 GMT+09:00 Olivier Matz <olivier.matz@6wind.com>:
> Hi Hiroyuki,
>
> Thanks for submitting a new version.
>
> There are some styling issues in the patch, I highlighted them below
> but you can check them by using checkpatch:
>
> DPDK_CHECKPATCH_PATH=/path/to/linux/checkpatch.pl \
> scripts/checkpatches.sh file.patch
>
>
> On 05/17/2016 06:35 PM, Hiroyuki Mikita wrote:
>> The rte_pktmbuf_detach() function should decrease refcnt on a direct
>> buffer.
>>
>> Signed-off-by: Hiroyuki Mikita <h.mikita89@gmail.com>
>>
>> [...]
>>
>> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
>> index 529debb..299b60e 100644
>> --- a/lib/librte_mbuf/rte_mbuf.h
>> +++ b/lib/librte_mbuf/rte_mbuf.h
>> @@ -1408,6 +1408,8 @@ static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool,
>> *
>> * After attachment we refer the mbuf we attached as 'indirect',
>> * while mbuf we attached to as 'direct'.
>> + * The direct mbuf's reference counter is incremented.
>> + *
>
> ERROR:TRAILING_WHITESPACE: trailing whitespace
> #82: FILE: lib/librte_mbuf/rte_mbuf.h:1412:
> + * $
>
>
>> * Right now, not supported:
>> * - attachment for already indirect mbuf (e.g. - mi has to be direct).
>> * - mbuf we trying to attach (mi) is used by someone else
>> @@ -1462,12 +1464,15 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m)
>> * - restore original mbuf address and length values.
>> * - reset pktmbuf data and data_len to their default values.
>> * All other fields of the given packet mbuf will be left intact.
>> + * - decrement the direct mbuf's reference counter.
>> + * When the reference counter becomes 0, the direct mbuf is freed.
>
> Minor comment here: I think something like that would be clearer:
>
> * - restore original mbuf address and length values.
> * - reset pktmbuf data and data_len to their default values.
> * - decrement the direct mbuf's reference counter. When the
> * reference counter becomes 0, the direct mbuf is freed.
> *
> * All other fields of the given packet mbuf will be left intact.
>
>
>> *
>> * @param m
>> * The indirect attached packet mbuf.
>> */
>> static inline void rte_pktmbuf_detach(struct rte_mbuf *m)
>> {
>> + struct rte_mbuf *md = rte_mbuf_from_indirect(m);
>> struct rte_mempool *mp = m->pool;
>> uint32_t mbuf_size, buf_len, priv_size;
>>
>> @@ -1482,6 +1487,10 @@ static inline void rte_pktmbuf_detach(struct rte_mbuf *m)
>> m->data_off = RTE_MIN(RTE_PKTMBUF_HEADROOM, (uint16_t)m->buf_len);
>> m->data_len = 0;
>> m->ol_flags = 0;
>> +
>> + if (rte_mbuf_refcnt_update(md, -1) == 0) {
>> + __rte_mbuf_raw_free(md);
>> + }
>> }
>
> WARNING:BRACES: braces {} are not necessary for single statement blocks
> #107: FILE: lib/librte_mbuf/rte_mbuf.h:1491:
> + if (rte_mbuf_refcnt_update(md, -1) == 0) {
> + __rte_mbuf_raw_free(md);
> + }
>
>
>>
>> static inline struct rte_mbuf* __attribute__((always_inline))
>> @@ -1491,15 +1500,9 @@ __rte_pktmbuf_prefree_seg(struct rte_mbuf *m)
>>
>> if (likely(rte_mbuf_refcnt_update(m, -1) == 0)) {
>>
>> - /* if this is an indirect mbuf, then
>> - * - detach mbuf
>> - * - free attached mbuf segment
>> - */
>> + /* if this is an indirect mbuf, it is detached. */
>> if (RTE_MBUF_INDIRECT(m)) {
>> - struct rte_mbuf *md = rte_mbuf_from_indirect(m);
>> rte_pktmbuf_detach(m);
>> - if (rte_mbuf_refcnt_update(md, -1) == 0)
>> - __rte_mbuf_raw_free(md);
>> }
>> return m;
>> }
>>
>
> It's not seen by checkpatch, but the braces could also be removed
> here.
>
> Apart from this, it looks good to me. I'm ok with not providing a
> compat function as we could consider it was a bug.
>
> Thanks for working on this.
>
> Olivier
>
^ permalink raw reply [flat|nested] 23+ messages in thread
* [dpdk-dev] [PATCH v4] mbuf: decrease refcnt when detaching
2016-05-17 16:35 ` [dpdk-dev] [PATCH v3] " Hiroyuki Mikita
2016-05-18 11:58 ` Olivier Matz
@ 2016-05-18 14:41 ` Hiroyuki Mikita
2016-05-18 15:51 ` Olivier Matz
1 sibling, 1 reply; 23+ messages in thread
From: Hiroyuki Mikita @ 2016-05-18 14:41 UTC (permalink / raw)
To: olivier.matz; +Cc: dev
The rte_pktmbuf_detach() function should decrease refcnt on a direct
buffer.
Signed-off-by: Hiroyuki Mikita <h.mikita89@gmail.com>
---
v4:
* fixed formatting.
* fixed doxygen comments of rte_pktmbuf_detach() to be clearer.
v3:
* fixed rte_pktmbuf_detach() to decrease refcnt.
* free the direct mbuf when refcnt becomes 0.
* added this issue to Resolved Issues in release notes.
v2:
* introduced a new function rte_pktmbuf_detach2() which decrease refcnt.
* marked rte_pktmbuf_detach() as deprecated.
* added comments about refcnt to rte_pktmbuf_attach() and rte_pktmbuf_detach().
* checked refcnt when detaching in unit tests.
* added this issue to release notes.
app/test/test_mbuf.c | 4 ++++
doc/guides/rel_notes/release_16_07.rst | 6 ++++++
lib/librte_mbuf/rte_mbuf.h | 23 ++++++++++++-----------
3 files changed, 22 insertions(+), 11 deletions(-)
diff --git a/app/test/test_mbuf.c b/app/test/test_mbuf.c
index 98ff93a..8460db7 100644
--- a/app/test/test_mbuf.c
+++ b/app/test/test_mbuf.c
@@ -511,10 +511,14 @@ test_attach_from_different_pool(void)
rte_pktmbuf_detach(clone);
if (c_data != rte_pktmbuf_mtod(clone, char *))
GOTO_FAIL("clone was not detached properly\n");
+ if (rte_mbuf_refcnt_read(m) != 2)
+ GOTO_FAIL("invalid refcnt in m\n");
rte_pktmbuf_detach(clone2);
if (c_data2 != rte_pktmbuf_mtod(clone2, char *))
GOTO_FAIL("clone2 was not detached properly\n");
+ if (rte_mbuf_refcnt_read(m) != 1)
+ GOTO_FAIL("invalid refcnt in m\n");
/* free the clones and the initial mbuf */
rte_pktmbuf_free(clone2);
diff --git a/doc/guides/rel_notes/release_16_07.rst b/doc/guides/rel_notes/release_16_07.rst
index 58c8ef9..a8c50c8 100644
--- a/doc/guides/rel_notes/release_16_07.rst
+++ b/doc/guides/rel_notes/release_16_07.rst
@@ -69,6 +69,12 @@ Drivers
Libraries
~~~~~~~~~
+* **mbuf: Fixed refcnt update when detaching.**
+
+ Fix the ``rte_pktmbuf_detach()`` function to decrement the direct
+ mbuf's reference counter. The previous behavior was not to affect
+ the reference counter. It lead a memory leak of the direct mbuf.
+
Examples
~~~~~~~~
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 7b92b88..48911a6 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -1412,6 +1412,8 @@ static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool,
*
* After attachment we refer the mbuf we attached as 'indirect',
* while mbuf we attached to as 'direct'.
+ * The direct mbuf's reference counter is incremented.
+ *
* Right now, not supported:
* - attachment for already indirect mbuf (e.g. - mi has to be direct).
* - mbuf we trying to attach (mi) is used by someone else
@@ -1465,13 +1467,17 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m)
*
* - restore original mbuf address and length values.
* - reset pktmbuf data and data_len to their default values.
- * All other fields of the given packet mbuf will be left intact.
+ * - decrement the direct mbuf's reference counter. When the
+ * reference counter becomes 0, the direct mbuf is freed.
+ *
+ * All other fields of the given packet mbuf will be left intact.
*
* @param m
* The indirect attached packet mbuf.
*/
static inline void rte_pktmbuf_detach(struct rte_mbuf *m)
{
+ struct rte_mbuf *md = rte_mbuf_from_indirect(m);
struct rte_mempool *mp = m->pool;
uint32_t mbuf_size, buf_len, priv_size;
@@ -1486,6 +1492,9 @@ static inline void rte_pktmbuf_detach(struct rte_mbuf *m)
m->data_off = RTE_MIN(RTE_PKTMBUF_HEADROOM, (uint16_t)m->buf_len);
m->data_len = 0;
m->ol_flags = 0;
+
+ if (rte_mbuf_refcnt_update(md, -1) == 0)
+ __rte_mbuf_raw_free(md);
}
static inline struct rte_mbuf* __attribute__((always_inline))
@@ -1494,17 +1503,9 @@ __rte_pktmbuf_prefree_seg(struct rte_mbuf *m)
__rte_mbuf_sanity_check(m, 0);
if (likely(rte_mbuf_refcnt_update(m, -1) == 0)) {
-
- /* if this is an indirect mbuf, then
- * - detach mbuf
- * - free attached mbuf segment
- */
- if (RTE_MBUF_INDIRECT(m)) {
- struct rte_mbuf *md = rte_mbuf_from_indirect(m);
+ /* if this is an indirect mbuf, it is detached. */
+ if (RTE_MBUF_INDIRECT(m))
rte_pktmbuf_detach(m);
- if (rte_mbuf_refcnt_update(md, -1) == 0)
- __rte_mbuf_raw_free(md);
- }
return m;
}
return NULL;
--
1.9.1
^ permalink raw reply [flat|nested] 23+ messages in thread