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  1. 28 Jul, 2014 10 commits
    • David S. Miller's avatar
      Merge branch 'inet_frag_kill_lru_list' · 6ceed786
      David S. Miller authored 
      Nikolay Aleksandrov says:

====================
inet: frag: cleanup and update

The end goal of this patchset is to remove the LRU list and to move the
frag eviction to a work queue. It also does a couple of necessary cleanups
and fixes. Brief patch descriptions:
Patches 1 - 3 inclusive: necessary clean ups
Patch 4 moves the eviction from the softirqs to a workqueue.
Patch 5 removes the nqueues counter which was protected by the LRU lock
Patch 6 removes the, by now unused, lru list.
Patch 7 moves the rebuild timer to the workqueue and schedules the rebuilds
        only if we've hit the maximum queue length on some of the chains.
Patch 8 migrate the rwlock to a seqlock since the rehash is usually a rare
        operation.
Patch 9 introduces an artificial global memory limit based on the value of
        init_net's high_thresh which is used to cap the high_thresh of the
        other namespaces. Also introduces some sane limits on the other
        tunables, and makes it impossible to have low_thresh > high_thresh.

Here are some numbers from running netperf before and after the patchset:
Each test consists of the following setting: -I 95,5 -i 15,10

1. Bound test (-T 4,4)
1.1 Virtio before the patchset -
MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.122.177 () port 0 AF_INET : +/-2.500% @ 95% conf.  : cpu bind
Socket  Message  Elapsed      Messages                   CPU      Service
Size    Size     Time         Okay Errors   Throughput   Util     Demand
bytes   bytes    secs            #      #   10^6bits/sec % SS     us/KB

212992   64000   30.00      722177      0    12325.1     34.55    2.025
212992           30.00      368020            6280.9     34.05    0.752

1.2 Virtio after the patchset -
MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.122.177 () port 0 AF_INET : +/-2.500% @ 95% conf.  : cpu bind
Socket  Message  Elapsed      Messages                   CPU      Service
Size    Size     Time         Okay Errors   Throughput   Util     Demand
bytes   bytes    secs            #      #   10^6bits/sec % SS     us/KB

212992   64000   30.00      727030      0    12407.9     35.45    1.876
212992           30.00      505405            8625.5     34.92    0.693

2. Virtio unbound test
2.1 Before the patchset
MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.122.177 () port 0 AF_INET : +/-2.500% @ 95% conf.
Socket  Message  Elapsed      Messages
Size    Size     Time         Okay Errors   Throughput
bytes   bytes    secs            #      #   10^6bits/sec

212992   64000   30.00      730008      0    12458.77
212992           30.00      416721           7112.02

2.2 After the patchset
MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.122.177 () port 0 AF_INET : +/-2.500% @ 95% conf.
Socket  Message  Elapsed      Messages
Size    Size     Time         Okay Errors   Throughput
bytes   bytes    secs            #      #   10^6bits/sec

212992   64000   30.00      731129      0    12477.89
212992           30.00      487707           8323.50

3. 10 gig unbound tests
3.1 Before the patchset
MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.133.1 () port 0 AF_INET : +/-2.500% @ 95% conf.
Socket  Message  Elapsed      Messages
Size    Size     Time         Okay Errors   Throughput
bytes   bytes    secs            #      #   10^6bits/sec

212992   64000   30.00      417209      0    7120.33
212992           30.00      416740           7112.33

3.2 After the patchset
MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.133.1 () port 0 AF_INET : +/-2.500% @ 95% conf.
Socket  Message  Elapsed      Messages
Size    Size     Time         Okay Errors   Throughput
bytes   bytes    secs            #      #   10^6bits/sec

212992   64000   30.00      438009      0    7475.33
212992           30.00      437630           7468.87

Given the options each netperf ran between 10 and 15 times for 30 seconds
to get the necessary confidence, also the tests themselves ran 3 times and
were consistent.
Another set of tests that I ran were parallel stress tests which consisted
of flooding the machine with fragmented packets from different sources with
frag timeout set to 0 (so there're lots of timeouts) and low_thresh set to
1 byte (so evictions are happening all the time) and on top of that running
a namespace create/destroy endless loop with network interfaces and
addresses that got flooded (for the brief periods they were up) in parallel.
This test ran for an hour without any issues.
====================
      6ceed786
    • Nikolay Aleksandrov's avatar
      inet: frag: set limits and make init_net's high_thresh limit global · 1bab4c75
      Nikolay Aleksandrov authored 
      This patch makes init_net's high_thresh limit to be the maximum for all
namespaces, thus introducing a global memory limit threshold equal to the
sum of the individual high_thresh limits which are capped.
It also introduces some sane minimums for low_thresh as it shouldn't be
able to drop below 0 (or > high_thresh in the unsigned case), and
overall low_thresh should not ever be above high_thresh, so we make the
following relations for a namespace:
init_net:
 high_thresh - max(not capped), min(init_net low_thresh)
 low_thresh - max(init_net high_thresh), min (0)

all other namespaces:
 high_thresh = max(init_net high_thresh), min(namespace's low_thresh)
 low_thresh = max(namespace's high_thresh), min(0)

The major issue with having low_thresh > high_thresh is that we'll
schedule eviction but never evict anything and thus rely only on the
timers.
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1bab4c75
    • Florian Westphal's avatar
      inet: frag: use seqlock for hash rebuild · ab1c724f
      Florian Westphal authored 
      rehash is rare operation, don't force readers to take
the read-side rwlock.

Instead, we only have to detect the (rare) case where
the secret was altered while we are trying to insert
a new inetfrag queue into the table.

If it was changed, drop the bucket lock and recompute
the hash to get the 'new' chain bucket that we have to
insert into.

Joint work with Nikolay Aleksandrov.
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ab1c724f
    • Florian Westphal's avatar
      inet: frag: remove periodic secret rebuild timer · e3a57d18
      Florian Westphal authored 
      merge functionality into the eviction workqueue.

Instead of rebuilding every n seconds, take advantage of the upper
hash chain length limit.

If we hit it, mark table for rebuild and schedule workqueue.
To prevent frequent rebuilds when we're completely overloaded,
don't rebuild more than once every 5 seconds.

ipfrag_secret_interval sysctl is now obsolete and has been marked as
deprecated, it still can be changed so scripts won't be broken but it
won't have any effect. A comment is left above each unused secret_timer
variable to avoid confusion.

Joint work with Nikolay Aleksandrov.
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e3a57d18
    • Florian Westphal's avatar
      inet: frag: remove lru list · 3fd588eb
      Florian Westphal authored 
      no longer used.
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      3fd588eb
    • Florian Westphal's avatar
      inet: frag: don't account number of fragment queues · 434d3054
      Florian Westphal authored 
      The 'nqueues' counter is protected by the lru list lock,
once thats removed this needs to be converted to atomic
counter.  Given this isn't used for anything except for
reporting it to userspace via /proc, just remove it.

We still report the memory currently used by fragment
reassembly queues.
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      434d3054
    • Florian Westphal's avatar
      inet: frag: move eviction of queues to work queue · b13d3cbf
      Florian Westphal authored 
      When the high_thresh limit is reached we try to toss the 'oldest'
incomplete fragment queues until memory limits are below the low_thresh
value.  This happens in softirq/packet processing context.

This has two drawbacks:

1) processors might evict a queue that was about to be completed
by another cpu, because they will compete wrt. resource usage and
resource reclaim.

2) LRU list maintenance is expensive.

But when constantly overloaded, even the 'least recently used' element is
recent, so removing 'lru' queue first is not 'fairer' than removing any
other fragment queue.

This moves eviction out of the fast path:

When the low threshold is reached, a work queue is scheduled
which then iterates over the table and removes the queues that exceed
the memory limits of the namespace. It sets a new flag called
INET_FRAG_EVICTED on the evicted queues so the proper counters will get
incremented when the queue is forcefully expired.

When the high threshold is reached, no more fragment queues are
created until we're below the limit again.

The LRU list is now unused and will be removed in a followup patch.

Joint work with Nikolay Aleksandrov.
Suggested-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b13d3cbf
    • Florian Westphal's avatar
      inet: frag: move evictor calls into frag_find function · 86e93e47
      Florian Westphal authored 
      First step to move eviction handling into a work queue.

We lose two spots that accounted evicted fragments in MIB counters.

Accounting will be restored since the upcoming work-queue evictor
invokes the frag queue timer callbacks instead.
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      86e93e47
    • Florian Westphal's avatar
      inet: frag: remove hash size assumptions from callers · fb3cfe6e
      Florian Westphal authored 
      hide actual hash size from individual users: The _find
function will now fold the given hash value into the required range.
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      fb3cfe6e
    • Florian Westphal's avatar
      inet: frag: constify match, hashfn and constructor arguments · 36c77782
      Florian Westphal authored 
      Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      36c77782
  3. 25 Jul, 2014 21 commits
  5. 24 Jul, 2014 9 commits
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