From c4b4d16e090e1b68d1d4d20a28757070982b9725 Mon Sep 17 00:00:00 2001 From: Ralph Campbell Date: Wed, 16 Apr 2008 21:09:26 -0700 Subject: IB/ipath: Make send buffers available for kernel if not allocated to user A fixed partitioning of send buffers is determined at driver load time for user processes and kernel use. Since send buffers are a scarce resource, it makes sense to allow the kernel to use the buffers if they are not in use by a user process. Also, eliminate code duplication for ipath_force_pio_avail_update(). Signed-off-by: Ralph Campbell Signed-off-by: Roland Dreier --- drivers/infiniband/hw/ipath/ipath_driver.c | 306 ++++++++++++++++++----------- 1 file changed, 194 insertions(+), 112 deletions(-) (limited to 'drivers/infiniband/hw/ipath/ipath_driver.c') diff --git a/drivers/infiniband/hw/ipath/ipath_driver.c b/drivers/infiniband/hw/ipath/ipath_driver.c index 1299171..216da97 100644 --- a/drivers/infiniband/hw/ipath/ipath_driver.c +++ b/drivers/infiniband/hw/ipath/ipath_driver.c @@ -317,7 +317,7 @@ static void ipath_verify_pioperf(struct ipath_devdata *dd) u32 *addr; u64 msecs, emsecs; - piobuf = ipath_getpiobuf(dd, &pbnum); + piobuf = ipath_getpiobuf(dd, 0, &pbnum); if (!piobuf) { dev_info(&dd->pcidev->dev, "No PIObufs for checking perf, skipping\n"); @@ -836,20 +836,8 @@ void ipath_disarm_piobufs(struct ipath_devdata *dd, unsigned first, ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch); spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags); } - - /* - * Disable PIOAVAILUPD, then re-enable, reading scratch in - * between. This seems to avoid a chip timing race that causes - * pioavail updates to memory to stop. We xor as we don't - * know the state of the bit when we're called. - */ - spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags); - ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, - dd->ipath_sendctrl ^ INFINIPATH_S_PIOBUFAVAILUPD); - ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch); - ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, - dd->ipath_sendctrl); - spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags); + /* on some older chips, update may not happen after cancel */ + ipath_force_pio_avail_update(dd); } /** @@ -1314,7 +1302,6 @@ static void ipath_update_pio_bufs(struct ipath_devdata *dd) * happens when all buffers are in use, so only cpu overhead, not * latency or bandwidth is affected. */ -#define _IPATH_ALL_CHECKBITS 0x5555555555555555ULL if (!dd->ipath_pioavailregs_dma) { ipath_dbg("Update shadow pioavail, but regs_dma NULL!\n"); return; @@ -1359,7 +1346,7 @@ static void ipath_update_pio_bufs(struct ipath_devdata *dd) piov = le64_to_cpu(dd->ipath_pioavailregs_dma[i ^ 1]); else piov = le64_to_cpu(dd->ipath_pioavailregs_dma[i]); - pchg = _IPATH_ALL_CHECKBITS & + pchg = dd->ipath_pioavailkernel[i] & ~(dd->ipath_pioavailshadow[i] ^ piov); pchbusy = pchg << INFINIPATH_SENDPIOAVAIL_BUSY_SHIFT; if (pchg && (pchbusy & dd->ipath_pioavailshadow[i])) { @@ -1410,27 +1397,63 @@ int ipath_setrcvhdrsize(struct ipath_devdata *dd, unsigned rhdrsize) return ret; } -/** - * ipath_getpiobuf - find an available pio buffer - * @dd: the infinipath device - * @pbufnum: the buffer number is placed here +/* + * debugging code and stats updates if no pio buffers available. + */ +static noinline void no_pio_bufs(struct ipath_devdata *dd) +{ + unsigned long *shadow = dd->ipath_pioavailshadow; + __le64 *dma = (__le64 *)dd->ipath_pioavailregs_dma; + + dd->ipath_upd_pio_shadow = 1; + + /* + * not atomic, but if we lose a stat count in a while, that's OK + */ + ipath_stats.sps_nopiobufs++; + if (!(++dd->ipath_consec_nopiobuf % 100000)) { + ipath_dbg("%u pio sends with no bufavail; dmacopy: " + "%llx %llx %llx %llx; shadow: %lx %lx %lx %lx\n", + dd->ipath_consec_nopiobuf, + (unsigned long long) le64_to_cpu(dma[0]), + (unsigned long long) le64_to_cpu(dma[1]), + (unsigned long long) le64_to_cpu(dma[2]), + (unsigned long long) le64_to_cpu(dma[3]), + shadow[0], shadow[1], shadow[2], shadow[3]); + /* + * 4 buffers per byte, 4 registers above, cover rest + * below + */ + if ((dd->ipath_piobcnt2k + dd->ipath_piobcnt4k) > + (sizeof(shadow[0]) * 4 * 4)) + ipath_dbg("2nd group: dmacopy: %llx %llx " + "%llx %llx; shadow: %lx %lx %lx %lx\n", + (unsigned long long)le64_to_cpu(dma[4]), + (unsigned long long)le64_to_cpu(dma[5]), + (unsigned long long)le64_to_cpu(dma[6]), + (unsigned long long)le64_to_cpu(dma[7]), + shadow[4], shadow[5], shadow[6], + shadow[7]); + } +} + +/* + * common code for normal driver pio buffer allocation, and reserved + * allocation. * * do appropriate marking as busy, etc. * returns buffer number if one found (>=0), negative number is error. - * Used by ipath_layer_send */ -u32 __iomem *ipath_getpiobuf(struct ipath_devdata *dd, u32 * pbufnum) +static u32 __iomem *ipath_getpiobuf_range(struct ipath_devdata *dd, + u32 *pbufnum, u32 first, u32 last, u32 firsti) { - int i, j, starti, updated = 0; - unsigned piobcnt, iter; + int i, j, updated = 0; + unsigned piobcnt; unsigned long flags; unsigned long *shadow = dd->ipath_pioavailshadow; u32 __iomem *buf; - piobcnt = (unsigned)(dd->ipath_piobcnt2k - + dd->ipath_piobcnt4k); - starti = dd->ipath_lastport_piobuf; - iter = piobcnt - starti; + piobcnt = last - first; if (dd->ipath_upd_pio_shadow) { /* * Minor optimization. If we had no buffers on last call, @@ -1438,12 +1461,10 @@ u32 __iomem *ipath_getpiobuf(struct ipath_devdata *dd, u32 * pbufnum) * if no buffers were updated, to be paranoid */ ipath_update_pio_bufs(dd); - /* we scanned here, don't do it at end of scan */ - updated = 1; - i = starti; + updated++; + i = first; } else - i = dd->ipath_lastpioindex; - + i = firsti; rescan: /* * while test_and_set_bit() is atomic, we do that and then the @@ -1451,104 +1472,141 @@ rescan: * of the remaining armlaunch errors. */ spin_lock_irqsave(&ipath_pioavail_lock, flags); - for (j = 0; j < iter; j++, i++) { - if (i >= piobcnt) - i = starti; - /* - * To avoid bus lock overhead, we first find a candidate - * buffer, then do the test and set, and continue if that - * fails. - */ - if (test_bit((2 * i) + 1, shadow) || - test_and_set_bit((2 * i) + 1, shadow)) + for (j = 0; j < piobcnt; j++, i++) { + if (i >= last) + i = first; + if (__test_and_set_bit((2 * i) + 1, shadow)) continue; /* flip generation bit */ - change_bit(2 * i, shadow); + __change_bit(2 * i, shadow); break; } spin_unlock_irqrestore(&ipath_pioavail_lock, flags); - if (j == iter) { - volatile __le64 *dma = dd->ipath_pioavailregs_dma; - - /* - * first time through; shadow exhausted, but may be real - * buffers available, so go see; if any updated, rescan - * (once) - */ + if (j == piobcnt) { if (!updated) { + /* + * first time through; shadow exhausted, but may be + * buffers available, try an update and then rescan. + */ ipath_update_pio_bufs(dd); - updated = 1; - i = starti; + updated++; + i = first; goto rescan; - } - dd->ipath_upd_pio_shadow = 1; - /* - * not atomic, but if we lose one once in a while, that's OK - */ - ipath_stats.sps_nopiobufs++; - if (!(++dd->ipath_consec_nopiobuf % 100000)) { - ipath_dbg( - "%u pio sends with no bufavail; dmacopy: " - "%llx %llx %llx %llx; shadow: " - "%lx %lx %lx %lx\n", - dd->ipath_consec_nopiobuf, - (unsigned long long) le64_to_cpu(dma[0]), - (unsigned long long) le64_to_cpu(dma[1]), - (unsigned long long) le64_to_cpu(dma[2]), - (unsigned long long) le64_to_cpu(dma[3]), - shadow[0], shadow[1], shadow[2], - shadow[3]); + } else if (updated == 1 && piobcnt <= + ((dd->ipath_sendctrl + >> INFINIPATH_S_UPDTHRESH_SHIFT) & + INFINIPATH_S_UPDTHRESH_MASK)) { /* - * 4 buffers per byte, 4 registers above, cover rest - * below + * for chips supporting and using the update + * threshold we need to force an update of the + * in-memory copy if the count is less than the + * thershold, then check one more time. */ - if ((dd->ipath_piobcnt2k + dd->ipath_piobcnt4k) > - (sizeof(shadow[0]) * 4 * 4)) - ipath_dbg("2nd group: dmacopy: %llx %llx " - "%llx %llx; shadow: %lx %lx " - "%lx %lx\n", - (unsigned long long) - le64_to_cpu(dma[4]), - (unsigned long long) - le64_to_cpu(dma[5]), - (unsigned long long) - le64_to_cpu(dma[6]), - (unsigned long long) - le64_to_cpu(dma[7]), - shadow[4], shadow[5], - shadow[6], shadow[7]); + ipath_force_pio_avail_update(dd); + ipath_update_pio_bufs(dd); + updated++; + i = first; + goto rescan; } + + no_pio_bufs(dd); buf = NULL; - goto bail; + } else { + if (i < dd->ipath_piobcnt2k) + buf = (u32 __iomem *) (dd->ipath_pio2kbase + + i * dd->ipath_palign); + else + buf = (u32 __iomem *) + (dd->ipath_pio4kbase + + (i - dd->ipath_piobcnt2k) * dd->ipath_4kalign); + if (pbufnum) + *pbufnum = i; } - /* - * set next starting place. Since it's just an optimization, - * it doesn't matter who wins on this, so no locking - */ - dd->ipath_lastpioindex = i + 1; - if (dd->ipath_upd_pio_shadow) - dd->ipath_upd_pio_shadow = 0; - if (dd->ipath_consec_nopiobuf) - dd->ipath_consec_nopiobuf = 0; - if (i < dd->ipath_piobcnt2k) - buf = (u32 __iomem *) (dd->ipath_pio2kbase + - i * dd->ipath_palign); - else - buf = (u32 __iomem *) - (dd->ipath_pio4kbase + - (i - dd->ipath_piobcnt2k) * dd->ipath_4kalign); - ipath_cdbg(VERBOSE, "Return piobuf%u %uk @ %p\n", - i, (i < dd->ipath_piobcnt2k) ? 2 : 4, buf); - if (pbufnum) - *pbufnum = i; + return buf; +} -bail: +/** + * ipath_getpiobuf - find an available pio buffer + * @dd: the infinipath device + * @plen: the size of the PIO buffer needed in 32-bit words + * @pbufnum: the buffer number is placed here + */ +u32 __iomem *ipath_getpiobuf(struct ipath_devdata *dd, u32 plen, u32 *pbufnum) +{ + u32 __iomem *buf; + u32 pnum, nbufs; + u32 first, lasti; + + if (plen + 1 >= IPATH_SMALLBUF_DWORDS) { + first = dd->ipath_piobcnt2k; + lasti = dd->ipath_lastpioindexl; + } else { + first = 0; + lasti = dd->ipath_lastpioindex; + } + nbufs = dd->ipath_piobcnt2k + dd->ipath_piobcnt4k; + buf = ipath_getpiobuf_range(dd, &pnum, first, nbufs, lasti); + + if (buf) { + /* + * Set next starting place. It's just an optimization, + * it doesn't matter who wins on this, so no locking + */ + if (plen + 1 >= IPATH_SMALLBUF_DWORDS) + dd->ipath_lastpioindexl = pnum + 1; + else + dd->ipath_lastpioindex = pnum + 1; + if (dd->ipath_upd_pio_shadow) + dd->ipath_upd_pio_shadow = 0; + if (dd->ipath_consec_nopiobuf) + dd->ipath_consec_nopiobuf = 0; + ipath_cdbg(VERBOSE, "Return piobuf%u %uk @ %p\n", + pnum, (pnum < dd->ipath_piobcnt2k) ? 2 : 4, buf); + if (pbufnum) + *pbufnum = pnum; + + } return buf; } /** + * ipath_chg_pioavailkernel - change which send buffers are available for kernel + * @dd: the infinipath device + * @start: the starting send buffer number + * @len: the number of send buffers + * @avail: true if the buffers are available for kernel use, false otherwise + */ +void ipath_chg_pioavailkernel(struct ipath_devdata *dd, unsigned start, + unsigned len, int avail) +{ + unsigned long flags; + unsigned end; + + /* There are two bits per send buffer (busy and generation) */ + start *= 2; + len *= 2; + end = start + len; + + /* Set or clear the generation bits. */ + spin_lock_irqsave(&ipath_pioavail_lock, flags); + while (start < end) { + if (avail) { + __clear_bit(start + INFINIPATH_SENDPIOAVAIL_BUSY_SHIFT, + dd->ipath_pioavailshadow); + __set_bit(start, dd->ipath_pioavailkernel); + } else { + __set_bit(start + INFINIPATH_SENDPIOAVAIL_BUSY_SHIFT, + dd->ipath_pioavailshadow); + __clear_bit(start, dd->ipath_pioavailkernel); + } + start += 2; + } + spin_unlock_irqrestore(&ipath_pioavail_lock, flags); +} + +/** * ipath_create_rcvhdrq - create a receive header queue * @dd: the infinipath device * @pd: the port data @@ -1664,6 +1722,30 @@ void ipath_cancel_sends(struct ipath_devdata *dd, int restore_sendctrl) ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch); } +/* + * Force an update of in-memory copy of the pioavail registers, when + * needed for any of a variety of reasons. We read the scratch register + * to make it highly likely that the update will have happened by the + * time we return. If already off (as in cancel_sends above), this + * routine is a nop, on the assumption that the caller will "do the + * right thing". + */ +void ipath_force_pio_avail_update(struct ipath_devdata *dd) +{ + unsigned long flags; + + spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags); + if (dd->ipath_sendctrl & INFINIPATH_S_PIOBUFAVAILUPD) { + ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, + dd->ipath_sendctrl & ~INFINIPATH_S_PIOBUFAVAILUPD); + ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch); + ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, + dd->ipath_sendctrl); + ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch); + } + spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags); +} + static void ipath_set_ib_lstate(struct ipath_devdata *dd, int linkcmd, int linitcmd) { -- cgit v1.1