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)
From: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
MODULE_PARM was actually breaking: recent gcc version optimize them out as
unused. It's time to replace the last users, which are generally in the
most unloved drivers anyway.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NULL noise removal, __iomem annotations, use of if_mii() instead of
open-coding it.
Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
- Use extern prefix for functions required.
- Removed a lot of wrappers, including t1_read/write_reg_4.
- Removed various macros, using native kernel calls now.
- Enumerated various #defines.
- Removed a lot of shared code which is not currently used in "NIC only" mode.
- Removed dead code.
Documentation/networking/cxgb.txt:
- Updated release notes for version 2.1.1
drivers/net/chelsio/ch_ethtool.h
- removed file, no longer using ETHTOOL namespace.
drivers/net/chelsio/common.h
- moved code from osdep.h to common.h
- added comment to #endif indicating which symbol it closes.
drivers/net/chelsio/cphy.h
- removed dead code.
- added comment to #endif indicating which symbol it closes.
drivers/net/chelsio/cxgb2.c
- use DMA_{32,64}BIT_MASK in include/linux/dma-mapping.h.
- removed unused code.
- use printk message for link info resembling drivers/net/mii.c.
- no longer using the MODULE_xxx namespace.
- no longer using "pci_" namespace.
- no longer using ETHTOOL namespace.
drivers/net/chelsio/cxgb2.h
- removed file, merged into common.h
drivers/net/chelsio/elmer0.h
- removed dead code.
- added various enums.
- added comment to #endif indicating which symbol it closes.
drivers/net/chelsio/espi.c
- removed various macros, using native kernel calls now.
- removed a lot of wrappers, including t1_read/write_reg_4.
drivers/net/chelsio/espi.h
- added comment to #endif indicating which symbol it closes.
drivers/net/chelsio/gmac.h
- added comment to #endif indicating which symbol it closes.
drivers/net/chelsio/mv88x201x.c
- changes to sync with Chelsio TOT.
drivers/net/chelsio/osdep.h
- removed file, consolidation. osdep was used to translate wrapper functions
since our code supports multiple OSs. removed wrappers.
drivers/net/chelsio/pm3393.c
- removed various macros, using native kernel calls now.
- removed a lot of wrappers, including t1_read/write_reg_4.
- removed unused code.
drivers/net/chelsio/regs.h
- added a few register entries for future and current feature support.
- added comment to #endif indicating which symbol it closes.
drivers/net/chelsio/sge.c
- rewrote large portion of scatter-gather engine to stabilize
performance.
- using u8/u16/u32 kernel types instead of __u8/__u16/__u32 compiler
types.
drivers/net/chelsio/sge.h
- rewrote large portion of scatter-gather engine to stabilize
performance.
- added comment to #endif indicating which symbol it closes.
drivers/net/chelsio/subr.c
- merged tp.c into subr.c
- removed various macros, using native kernel calls now.
- removed a lot of wrappers, including t1_read/write_reg_4.
- removed unused code.
drivers/net/chelsio/suni1x10gexp_regs.h
- modified copyright and authorship of file.
- added comment to #endif indicating which symbol it closes.
drivers/net/chelsio/tp.c
- removed file, merged into subr.c.
drivers/net/chelsio/tp.h
- removed file.
include/linux/pci_ids.h
- patched to include PCI_VENDOR_ID_CHELSIO 0x1425, removed define from
our code.
A Linux driver for the Chelsio 10Gb Ethernet Network Controller by Chelsio
(http://www.chelsio.com). This driver supports the Chelsio N210 NIC and is
backward compatible with the Chelsio N110 model 10Gb NICs. It supports
AMD64, EM64T and x86 systems.
Signed-off-by: Tina Yang <tinay@chelsio.com>
Signed-off-by: Scott Bardone <sbardone@chelsio.com>
Signed-off-by: Christoph Lameter <christoph@lameter.com>
Adrian said:
- my3126.c is unused (because t1_my3126_ops isn't used anywhere)
- what are the EXTRA_CFLAGS in drivers/net/chelsio/Makefile for?
- $(cxgb-y) in drivers/net/chelsio/Makefile seems to be unneeded
- completely unused global functions:
- espi.c: t1_espi_get_intr_counts
- sge.c: t1_sge_get_intr_counts
- the following functions can be made static:
- sge.c: t1_espi_workaround
- sge.c: t1_sge_tx
- subr.c: __t1_tpi_read
- subr.c: __t1_tpi_write
- subr.c: t1_wait_op_done
shemminger said:
The performance recommendations in cxgb.txt are common to all fast devices,
and should be in one file rather than just for this device. I would rather
see ip-sysctl.txt updated or a new file on tuning recommendations started.
Some of them have consequences that aren't documented well.
For example, turning off TCP timestamps risks data corruption from sequence wrap.
A new driver shouldn't need so may #ifdef's unless you want to putit on older
vendor versions of 2.4
Some accessor and wrapper functions like:
t1_pci_read_config_4
adapter_name
t1_malloc
are just annoying noise.
Why have useless dead code like:
/* Interrupt handler */
+static int pm3393_interrupt_handler(struct cmac *cmac)
+{
+ u32 master_intr_status;
+/*
+ 1. Read master interrupt register.
+ 2. Read BLOCK's interrupt status registers.
+ 3. Handle BLOCK interrupts.
+*/
Jeff said:
step 1: kill all the OS wrappers.
And do you really need hooks for multiple MACs, when only one MAC is
really supported? Typically these hooks are at a higher level anyway --
struct net_device.
From: Christoph Lameter <christoph@lameter
Driver modified as suggested by Pekka Enberg, Stephen Hemminger and Andrian
Bunk. Reduces the size of the driver to ~260k.
- clean up tabs
- removed my3126.c
- removed 85% of suni1x10gexp_regs.h
- removed 80% of regs.h
- removed various calls, renamed variables/functions.
- removed system specific and other wrappers (usleep, msleep)
- removed dead code
- dropped redundant casts in osdep.h
- dropped redundant check of kfree
- dropped weird code (MODVERSIONS stuff)
- reduced number of #ifdefs
- use kcalloc now instead of kmalloc
- Add information about known issues with the driver
- Add information about authors
Signed-off-by: Scott Bardone <sbardone@chelsio.com>
Signed-off-by: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
diff -puN /dev/null Documentation/networking/cxgb.txt
David Howells