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Eric Dumazet authored
In commit ed98df33 ("net: use __GFP_NORETRY for high order allocations") we tried to address one issue caused by order-3 allocations. We still observe high latencies and system overhead in situations where compaction is not successful. Instead of trying order-3, order-2, and order-1, do a single order-3 best effort and immediately fallback to plain order-0. This mimics slub strategy to fallback to slab min order if the high order allocation used for performance failed. Order-3 allocations give a performance boost only if they can be done without recurring and expensive memory scan. Quoting David : The page allocator relies on synchronous (sync light) memory compaction after direct reclaim for allocations that don't retry and deferred compaction doesn't work with this strategy because the allocation order is always decreasing from the previous failed attempt. This means sync light compaction will always be encountered if memory cannot be defragmented or reclaimed several times during the skb_page_frag_refill() iteration. Signed-off-by:
Eric Dumazet <edumazet@google.com> Acked-by:
David Rientjes <rientjes@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
Eric Dumazet authoredIn commit ed98df33 ("net: use __GFP_NORETRY for high order allocations") we tried to address one issue caused by order-3 allocations. We still observe high latencies and system overhead in situations where compaction is not successful. Instead of trying order-3, order-2, and order-1, do a single order-3 best effort and immediately fallback to plain order-0. This mimics slub strategy to fallback to slab min order if the high order allocation used for performance failed. Order-3 allocations give a performance boost only if they can be done without recurring and expensive memory scan. Quoting David : The page allocator relies on synchronous (sync light) memory compaction after direct reclaim for allocations that don't retry and deferred compaction doesn't work with this strategy because the allocation order is always decreasing from the previous failed attempt. This means sync light compaction will always be encountered if memory cannot be defragmented or reclaimed several times during the skb_page_frag_refill() iteration. Signed-off-by:
Eric Dumazet <edumazet@google.com> Acked-by:
David Rientjes <rientjes@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
mkcompile_h 2.46 KiB
#!/bin/sh
TARGET=$1
ARCH=$2
SMP=$3
PREEMPT=$4
CC=$5
vecho() { [ "${quiet}" = "silent_" ] || echo "$@" ; }
# If compile.h exists already and we don't own autoconf.h
# (i.e. we're not the same user who did make *config), don't
# modify compile.h
# So "sudo make install" won't change the "compiled by <user>"
# do "compiled by root"
if [ -r $TARGET -a ! -O include/generated/autoconf.h ]; then
vecho " SKIPPED $TARGET"
exit 0
fi
# Do not expand names
set -f
# Fix the language to get consistent output
LC_ALL=C
export LC_ALL
if [ -z "$KBUILD_BUILD_VERSION" ]; then
if [ -r .version ]; then
VERSION=`cat .version`
else
VERSION=0
echo 0 > .version
fi
else
VERSION=$KBUILD_BUILD_VERSION
fi
if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
TIMESTAMP=`date`
else
TIMESTAMP=$KBUILD_BUILD_TIMESTAMP
fi
if test -z "$KBUILD_BUILD_USER"; then
LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/')
else
LINUX_COMPILE_BY=$KBUILD_BUILD_USER
fi
if test -z "$KBUILD_BUILD_HOST"; then
LINUX_COMPILE_HOST=`hostname`
else
LINUX_COMPILE_HOST=$KBUILD_BUILD_HOST
fi
UTS_VERSION="#$VERSION"
CONFIG_FLAGS=""
if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
if [ -n "$PREEMPT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"; fi
UTS_VERSION="$UTS_VERSION $CONFIG_FLAGS $TIMESTAMP"
# Truncate to maximum length
UTS_LEN=64
UTS_TRUNCATE="cut -b -$UTS_LEN"
# Generate a temporary compile.h
( echo /\* This file is auto generated, version $VERSION \*/
if [ -n "$CONFIG_FLAGS" ] ; then echo "/* $CONFIG_FLAGS */"; fi
echo \#define UTS_MACHINE \"$ARCH\"
echo \#define UTS_VERSION \"`echo $UTS_VERSION | $UTS_TRUNCATE`\"
echo \#define LINUX_COMPILE_BY \"`echo $LINUX_COMPILE_BY | $UTS_TRUNCATE`\"
echo \#define LINUX_COMPILE_HOST \"`echo $LINUX_COMPILE_HOST | $UTS_TRUNCATE`\"
echo \#define LINUX_COMPILER \"`$CC -v 2>&1 | tail -n 1`\"
) > .tmpcompile
# Only replace the real compile.h if the new one is different,
# in order to preserve the timestamp and avoid unnecessary
# recompilations.
# We don't consider the file changed if only the date/time changed.
# A kernel config change will increase the generation number, thus
# causing compile.h to be updated (including date/time) due to the
# changed comment in the
# first line.
if [ -r $TARGET ] && \
grep -v 'UTS_VERSION' $TARGET > .tmpver.1 && \
grep -v 'UTS_VERSION' .tmpcompile > .tmpver.2 && \
cmp -s .tmpver.1 .tmpver.2; then
rm -f .tmpcompile
else
vecho " UPD $TARGET"
mv -f .tmpcompile $TARGET
fi
rm -f .tmpver.1 .tmpver.2