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| author | John Crispin <john@phrozen.org> | 2016-12-25 20:11:34 +0100 |
|---|---|---|
| committer | John Crispin <john@phrozen.org> | 2017-08-05 08:46:36 +0200 |
| commit | 74d00a8c3849c1340efd713eb94b786e304c201f (patch) | |
| tree | de481743de61c34da96ab5f9dba3af3edcfb8260 /target/linux/generic/pending-3.18/080-19-fib_trie-Use-index-0ul-n-bits-instead-of-index-n-bit.patch | |
| parent | de350550ef648d9728351b986b0516fa29465c45 (diff) | |
| download | upstream-74d00a8c3849c1340efd713eb94b786e304c201f.tar.gz upstream-74d00a8c3849c1340efd713eb94b786e304c201f.tar.bz2 upstream-74d00a8c3849c1340efd713eb94b786e304c201f.zip | |
kernel: split patches folder up into backport, pending and hack folders
* properly format/comment all patches
* merge debloat patches
* merge Kconfig patches
* merge swconfig patches
* merge hotplug patches
* drop 200-fix_localversion.patch - upstream
* drop 222-arm_zimage_none.patch - unused
* drop 252-mv_cesa_depends.patch - no longer required
* drop 410-mtd-move-forward-declaration-of-struct-mtd_info.patch - unused
* drop 661-fq_codel_keep_dropped_stats.patch - outdated
* drop 702-phy_add_aneg_done_function.patch - upstream
* drop 840-rtc7301.patch - unused
* drop 841-rtc_pt7c4338.patch - upstream
* drop 921-use_preinit_as_init.patch - unused
* drop spio-gpio-old and gpio-mmc - unused
Signed-off-by: John Crispin <john@phrozen.org>
Diffstat (limited to 'target/linux/generic/pending-3.18/080-19-fib_trie-Use-index-0ul-n-bits-instead-of-index-n-bit.patch')
| -rw-r--r-- | target/linux/generic/pending-3.18/080-19-fib_trie-Use-index-0ul-n-bits-instead-of-index-n-bit.patch | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/target/linux/generic/pending-3.18/080-19-fib_trie-Use-index-0ul-n-bits-instead-of-index-n-bit.patch b/target/linux/generic/pending-3.18/080-19-fib_trie-Use-index-0ul-n-bits-instead-of-index-n-bit.patch new file mode 100644 index 0000000000..d5fc112563 --- /dev/null +++ b/target/linux/generic/pending-3.18/080-19-fib_trie-Use-index-0ul-n-bits-instead-of-index-n-bit.patch @@ -0,0 +1,52 @@ +From: Alexander Duyck <alexander.h.duyck@redhat.com> +Date: Thu, 22 Jan 2015 15:51:08 -0800 +Subject: [PATCH] fib_trie: Use index & (~0ul << n->bits) instead of index >> + n->bits + +In doing performance testing and analysis of the changes I recently found +that by shifting the index I had created an unnecessary dependency. + +I have updated the code so that we instead shift a mask by bits and then +just test against that as that should save us about 2 CPU cycles since we +can generate the mask while the key and pos are being processed. + +Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + +--- a/net/ipv4/fib_trie.c ++++ b/net/ipv4/fib_trie.c +@@ -961,12 +961,12 @@ static struct tnode *fib_find_node(struc + * prefix plus zeros for the bits in the cindex. The index + * is the difference between the key and this value. From + * this we can actually derive several pieces of data. +- * if !(index >> bits) +- * we know the value is cindex +- * else ++ * if (index & (~0ul << bits)) + * we have a mismatch in skip bits and failed ++ * else ++ * we know the value is cindex + */ +- if (index >> n->bits) ++ if (index & (~0ul << n->bits)) + return NULL; + + /* we have found a leaf. Prefixes have already been compared */ +@@ -1301,12 +1301,12 @@ int fib_table_lookup(struct fib_table *t + * prefix plus zeros for the "bits" in the prefix. The index + * is the difference between the key and this value. From + * this we can actually derive several pieces of data. +- * if !(index >> bits) +- * we know the value is child index +- * else ++ * if (index & (~0ul << bits)) + * we have a mismatch in skip bits and failed ++ * else ++ * we know the value is cindex + */ +- if (index >> n->bits) ++ if (index & (~0ul << n->bits)) + break; + + /* we have found a leaf. Prefixes have already been compared */ |