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| author | Eric Dumazet <edumazet@google.com> | 2017-09-19 16:27:04 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-09-19 16:32:23 -0700 |
| commit | 4a336a23d619e96aef37d4d054cfadcdd1b581ba (patch) | |
| tree | 1d25fd3298cfa0a260e1b3fa4d10d357d8e53292 /lib/strncpy_from_user.c | |
| parent | 16dff336b33d87c15d9cbe933cfd275aae2a8251 (diff) | |
| download | linux-4a336a23d619e96aef37d4d054cfadcdd1b581ba.tar.gz linux-4a336a23d619e96aef37d4d054cfadcdd1b581ba.tar.bz2 linux-4a336a23d619e96aef37d4d054cfadcdd1b581ba.zip | |
kobject: copy env blob in one go
No need to iterate over strings, just copy in one efficient memcpy() call.
Tested:
time perf record "(for f in `seq 1 3000` ; do ip netns add tast$f; done)"
[ perf record: Woken up 10 times to write data ]
[ perf record: Captured and wrote 8.224 MB perf.data (~359301 samples) ]
real 0m52.554s # instead of 1m7.492s
user 0m0.309s
sys 0m51.375s # instead of 1m6.875s
9.88% ip [kernel.kallsyms] [k] netlink_broadcast_filtered
8.86% ip [kernel.kallsyms] [k] string
7.37% ip [kernel.kallsyms] [k] __ip6addrlbl_add
5.68% ip [kernel.kallsyms] [k] netlink_has_listeners
5.52% ip [kernel.kallsyms] [k] memcpy_erms
4.76% ip [kernel.kallsyms] [k] __alloc_skb
4.54% ip [kernel.kallsyms] [k] vsnprintf
3.94% ip [kernel.kallsyms] [k] format_decode
3.80% ip [kernel.kallsyms] [k] kmem_cache_alloc_node_trace
3.71% ip [kernel.kallsyms] [k] kmem_cache_alloc_node
3.66% ip [kernel.kallsyms] [k] kobject_uevent_env
3.38% ip [kernel.kallsyms] [k] strlen
2.65% ip [kernel.kallsyms] [k] _raw_spin_lock_irqsave
2.20% ip [kernel.kallsyms] [k] kfree
2.09% ip [kernel.kallsyms] [k] memset_erms
2.07% ip [kernel.kallsyms] [k] ___cache_free
1.95% ip [kernel.kallsyms] [k] kmem_cache_free
1.91% ip [kernel.kallsyms] [k] _raw_read_lock
1.45% ip [kernel.kallsyms] [k] ksize
1.25% ip [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore
1.00% ip [kernel.kallsyms] [k] widen_string
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib/strncpy_from_user.c')
0 files changed, 0 insertions, 0 deletions