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Code Issues Releases Activity

Increased the number of Tx segments from 13 to 29 to reduce the need to

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recopy to near zero. Wrote the necessary code to recopy the mbuf chain
into another buffer if there are too many mbufs in the chain.
This commit is contained in:
David Greenman 1995-12-05 11:49:55 +00:00
parent 140dbd4767
commit 23a0ed7c08
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=12633
4 changed files with 68 additions and 16 deletions
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38
sys/dev/fxp/if_fxp.c
View File

@ -29,7 +29,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: if_fxp.c,v 1.2 1995/12/01 22:41:56 davidg Exp $
* $Id: if_fxp.c,v 1.3 1995/12/05 02:01:51 davidg Exp $
*/
/*
@ -171,9 +171,14 @@ DATA_SET(pcidevice_set, fxp_device);
/*
* Number of DMA segments in a TxCB. Note that this is carefully
* chosen to make the total struct size an even power of two.
* chosen to make the total struct size an even power of two. It's
* critical that no TxCB be split across a page boundry since
* no attempt is made to allocate physically contiguous memory.
*
* XXX - don't forget to change the hard-coded constant in the
* fxp_cb_tx struct (defined in if_fxpreg.h), too!
*/
#define FXP_NTXSEG 13
#define FXP_NTXSEG 29
/*
* Number of receive frame area buffers. These are large so chose
@ -449,6 +454,7 @@ fxp_start(ifp)
* the transmit buffers descriptors with the physical address
* and size of the mbuf.
*/
tbdinit:
for (m = mb_head, segment = 0; m != NULL; m = m->m_next) {
if (m->m_len != 0) {
if (segment == FXP_NTXSEG)
@ -460,14 +466,34 @@ fxp_start(ifp)
}
}
if (m != NULL && segment == FXP_NTXSEG) {
struct mbuf *mn;
/*
* We ran out of segments. We have to recopy this mbuf
* chain first.
*/
panic("fxp%d: ran out of segments", ifp->if_unit);
} else {
txp->tbd_number = segment;
MGETHDR(mn, M_DONTWAIT, MT_DATA);
if (mn == NULL) {
m_freem(mb_head);
return;
}
if (mb_head->m_pkthdr.len > MHLEN) {
MCLGET(mn, M_DONTWAIT);
if ((mn->m_flags & M_EXT) == 0) {
m_freem(mn);
m_freem(mb_head);
return;
}
}
m_copydata(mb_head, 0, mb_head->m_pkthdr.len, mtod(mn, caddr_t));
mn->m_pkthdr.len = mn->m_len = mb_head->m_pkthdr.len;
m_freem(mb_head);
mb_head = mn;
goto tbdinit;
}
txp->tbd_number = segment;
/*
* Finish the initialization of this TxCB.
*/

4
sys/dev/fxp/if_fxpreg.h
View File

@ -29,7 +29,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id$
* $Id: if_fxpreg.h,v 1.1 1995/11/28 23:55:26 davidg Exp $
*/
#define FXP_VENDORID_INTEL 0x8086
@ -177,7 +177,7 @@ struct fxp_cb_tx {
/*
* The following isn't actually part of the TxCB.
*/
volatile struct fxp_tbd tbd[13];
volatile struct fxp_tbd tbd[29];
struct mbuf *mb_head;
struct fxp_cb_tx *next;
};

38
sys/pci/if_fxp.c
View File

@ -29,7 +29,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: if_fxp.c,v 1.2 1995/12/01 22:41:56 davidg Exp $
* $Id: if_fxp.c,v 1.3 1995/12/05 02:01:51 davidg Exp $
*/
/*
@ -171,9 +171,14 @@ DATA_SET(pcidevice_set, fxp_device);
/*
* Number of DMA segments in a TxCB. Note that this is carefully
* chosen to make the total struct size an even power of two.
* chosen to make the total struct size an even power of two. It's
* critical that no TxCB be split across a page boundry since
* no attempt is made to allocate physically contiguous memory.
*
* XXX - don't forget to change the hard-coded constant in the
* fxp_cb_tx struct (defined in if_fxpreg.h), too!
*/
#define FXP_NTXSEG 13
#define FXP_NTXSEG 29
/*
* Number of receive frame area buffers. These are large so chose
@ -449,6 +454,7 @@ fxp_start(ifp)
* the transmit buffers descriptors with the physical address
* and size of the mbuf.
*/
tbdinit:
for (m = mb_head, segment = 0; m != NULL; m = m->m_next) {
if (m->m_len != 0) {
if (segment == FXP_NTXSEG)
@ -460,14 +466,34 @@ fxp_start(ifp)
}
}
if (m != NULL && segment == FXP_NTXSEG) {
struct mbuf *mn;
/*
* We ran out of segments. We have to recopy this mbuf
* chain first.
*/
panic("fxp%d: ran out of segments", ifp->if_unit);
} else {
txp->tbd_number = segment;
MGETHDR(mn, M_DONTWAIT, MT_DATA);
if (mn == NULL) {
m_freem(mb_head);
return;
}
if (mb_head->m_pkthdr.len > MHLEN) {
MCLGET(mn, M_DONTWAIT);
if ((mn->m_flags & M_EXT) == 0) {
m_freem(mn);
m_freem(mb_head);
return;
}
}
m_copydata(mb_head, 0, mb_head->m_pkthdr.len, mtod(mn, caddr_t));
mn->m_pkthdr.len = mn->m_len = mb_head->m_pkthdr.len;
m_freem(mb_head);
mb_head = mn;
goto tbdinit;
}
txp->tbd_number = segment;
/*
* Finish the initialization of this TxCB.
*/

4
sys/pci/if_fxpreg.h
View File

@ -29,7 +29,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id$
* $Id: if_fxpreg.h,v 1.1 1995/11/28 23:55:26 davidg Exp $
*/
#define FXP_VENDORID_INTEL 0x8086
@ -177,7 +177,7 @@ struct fxp_cb_tx {
/*
* The following isn't actually part of the TxCB.
*/
volatile struct fxp_tbd tbd[13];
volatile struct fxp_tbd tbd[29];
struct mbuf *mb_head;
struct fxp_cb_tx *next;
};