Revision 59a32e2ce5eb809967cac4e718bc527beca83c59 authored by Eric Dumazet on 23 March 2012, 22:02:53 UTC, committed by Linus Torvalds on 23 March 2012, 23:58:42 UTC
On a typical 16 cpus machine, "cat /proc/stat" gives more than 4096 bytes, and is slow : # strace -T -o /tmp/STRACE cat /proc/stat | wc -c 5826 # grep "cpu " /tmp/STRACE read(0, "cpu 1949310 19 2144714 12117253"..., 32768) = 5826 <0.001504> Thats partly because show_stat() must be called twice since initial buffer size is too small (4096 bytes for less than 32 possible cpus) Fix this by : 1) Taking into account nr_irqs in the initial buffer sizing. 2) Using ksize() to allow better filling of initial buffer. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Makefile.headersinst
# ==========================================================================
# Installing headers
#
# header-y - list files to be installed. They are preprocessed
# to remove __KERNEL__ section of the file
# objhdr-y - Same as header-y but for generated files
# genhdr-y - Same as objhdr-y but in a generated/ directory
#
# ==========================================================================
# called may set destination dir (when installing to asm/)
_dst := $(if $(dst),$(dst),$(obj))
# generated header directory
gen := $(if $(gen),$(gen),$(subst include/,include/generated/,$(obj)))
kbuild-file := $(srctree)/$(obj)/Kbuild
include $(kbuild-file)
_dst := $(if $(destination-y),$(destination-y),$(_dst))
include scripts/Kbuild.include
install := $(INSTALL_HDR_PATH)/$(_dst)
header-y := $(sort $(header-y))
subdirs := $(patsubst %/,%,$(filter %/, $(header-y)))
header-y := $(filter-out %/, $(header-y))
# files used to track state of install/check
install-file := $(install)/.install
check-file := $(install)/.check
# generic-y list all files an architecture uses from asm-generic
# Use this to build a list of headers which require a wrapper
wrapper-files := $(filter $(header-y), $(generic-y))
# all headers files for this dir
header-y := $(filter-out $(generic-y), $(header-y))
all-files := $(header-y) $(objhdr-y) $(genhdr-y) $(wrapper-files)
input-files := $(addprefix $(srctree)/$(obj)/,$(header-y)) \
$(addprefix $(objtree)/$(obj)/,$(objhdr-y)) \
$(addprefix $(objtree)/$(gen)/,$(genhdr-y))
output-files := $(addprefix $(install)/, $(all-files))
# Work out what needs to be removed
oldheaders := $(patsubst $(install)/%,%,$(wildcard $(install)/*.h))
unwanted := $(filter-out $(all-files),$(oldheaders))
# Prefix unwanted with full paths to $(INSTALL_HDR_PATH)
unwanted-file := $(addprefix $(install)/, $(unwanted))
printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))
quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
file$(if $(word 2, $(all-files)),s))
cmd_install = \
$(PERL) $< $(srctree)/$(obj) $(install) $(SRCARCH) $(header-y); \
$(PERL) $< $(objtree)/$(obj) $(install) $(SRCARCH) $(objhdr-y); \
$(PERL) $< $(objtree)/$(gen) $(install) $(SRCARCH) $(genhdr-y); \
for F in $(wrapper-files); do \
echo "\#include <asm-generic/$$F>" > $(install)/$$F; \
done; \
touch $@
quiet_cmd_remove = REMOVE $(unwanted)
cmd_remove = rm -f $(unwanted-file)
quiet_cmd_check = CHECK $(printdir) ($(words $(all-files)) files)
# Headers list can be pretty long, xargs helps to avoid
# the "Argument list too long" error.
cmd_check = for f in $(all-files); do \
echo "$(install)/$${f}"; done \
| xargs \
$(PERL) $< $(INSTALL_HDR_PATH)/include $(SRCARCH); \
touch $@
PHONY += __headersinst __headerscheck
ifndef HDRCHECK
# Rules for installing headers
__headersinst: $(subdirs) $(install-file)
@:
targets += $(install-file)
$(install-file): scripts/headers_install.pl $(input-files) FORCE
$(if $(unwanted),$(call cmd,remove),)
$(if $(wildcard $(dir $@)),,$(shell mkdir -p $(dir $@)))
$(call if_changed,install)
else
__headerscheck: $(subdirs) $(check-file)
@:
targets += $(check-file)
$(check-file): scripts/headers_check.pl $(output-files) FORCE
$(call if_changed,check)
endif
# Recursion
hdr-inst := -rR -f $(srctree)/scripts/Makefile.headersinst obj
.PHONY: $(subdirs)
$(subdirs):
$(Q)$(MAKE) $(hdr-inst)=$(obj)/$@ dst=$(_dst)/$@
targets := $(wildcard $(sort $(targets)))
cmd_files := $(wildcard \
$(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
ifneq ($(cmd_files),)
include $(cmd_files)
endif
.PHONY: $(PHONY)
PHONY += FORCE
FORCE: ;
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