![David Howells](/assets/img/avatar_default.png)
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
97 lines
5.1 KiB
C
97 lines
5.1 KiB
C
/*****************************************************************************
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* *
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* File: sge.h *
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* $Revision: 1.11 $ *
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* $Date: 2005/06/21 22:10:55 $ *
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* Description: *
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* part of the Chelsio 10Gb Ethernet Driver. *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License, version 2, as *
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* published by the Free Software Foundation. *
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* *
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* You should have received a copy of the GNU General Public License along *
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* with this program; if not, write to the Free Software Foundation, Inc., *
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
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* *
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED *
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF *
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. *
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* *
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* http://www.chelsio.com *
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* *
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* Copyright (c) 2003 - 2005 Chelsio Communications, Inc. *
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* All rights reserved. *
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* *
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* Maintainers: maintainers@chelsio.com *
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* *
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* Authors: Dimitrios Michailidis <dm@chelsio.com> *
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* Tina Yang <tainay@chelsio.com> *
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* Felix Marti <felix@chelsio.com> *
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* Scott Bardone <sbardone@chelsio.com> *
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* Kurt Ottaway <kottaway@chelsio.com> *
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* Frank DiMambro <frank@chelsio.com> *
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* *
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* History: *
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* *
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****************************************************************************/
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#ifndef _CXGB_SGE_H_
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#define _CXGB_SGE_H_
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#include <linux/types.h>
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#include <linux/interrupt.h>
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#include <asm/byteorder.h>
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struct sge_intr_counts {
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unsigned int respQ_empty; /* # times respQ empty */
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unsigned int respQ_overflow; /* # respQ overflow (fatal) */
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unsigned int freelistQ_empty; /* # times freelist empty */
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unsigned int pkt_too_big; /* packet too large (fatal) */
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unsigned int pkt_mismatch;
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unsigned int cmdQ_full[3]; /* not HW IRQ, host cmdQ[] full */
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unsigned int cmdQ_restarted[3];/* # of times cmdQ X was restarted */
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unsigned int ethernet_pkts; /* # of Ethernet packets received */
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unsigned int offload_pkts; /* # of offload packets received */
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unsigned int offload_bundles; /* # of offload pkt bundles delivered */
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unsigned int pure_rsps; /* # of non-payload responses */
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unsigned int unhandled_irqs; /* # of unhandled interrupts */
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unsigned int tx_ipfrags;
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unsigned int tx_reg_pkts;
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unsigned int tx_lso_pkts;
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unsigned int tx_do_cksum;
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};
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struct sge_port_stats {
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unsigned long rx_cso_good; /* # of successful RX csum offloads */
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unsigned long tx_cso; /* # of TX checksum offloads */
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unsigned long vlan_xtract; /* # of VLAN tag extractions */
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unsigned long vlan_insert; /* # of VLAN tag extractions */
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unsigned long tso; /* # of TSO requests */
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unsigned long rx_drops; /* # of packets dropped due to no mem */
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};
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struct sk_buff;
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struct net_device;
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struct adapter;
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struct sge_params;
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struct sge;
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struct sge *t1_sge_create(struct adapter *, struct sge_params *);
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int t1_sge_configure(struct sge *, struct sge_params *);
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int t1_sge_set_coalesce_params(struct sge *, struct sge_params *);
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void t1_sge_destroy(struct sge *);
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irq_handler_t t1_select_intr_handler(adapter_t *adapter);
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int t1_start_xmit(struct sk_buff *skb, struct net_device *dev);
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void t1_set_vlan_accel(struct adapter *adapter, int on_off);
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void t1_sge_start(struct sge *);
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void t1_sge_stop(struct sge *);
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int t1_sge_intr_error_handler(struct sge *);
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void t1_sge_intr_enable(struct sge *);
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void t1_sge_intr_disable(struct sge *);
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void t1_sge_intr_clear(struct sge *);
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const struct sge_intr_counts *t1_sge_get_intr_counts(struct sge *sge);
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const struct sge_port_stats *t1_sge_get_port_stats(struct sge *sge, int port);
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#endif /* _CXGB_SGE_H_ */
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