linux.git/ipc/util.h, branch v4.14-rc2

Merge branch 'work.ipc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2017-09-15T00:37:26+00:00

Pull ipc compat cleanup and 64-bit time_t from Al Viro:
 "IPC copyin/copyout sanitizing, including 64bit time_t work from Deepa
  Dinamani"

* 'work.ipc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  utimes: Make utimes y2038 safe
  ipc: shm: Make shmid_kernel timestamps y2038 safe
  ipc: sem: Make sem_array timestamps y2038 safe
  ipc: msg: Make msg_queue timestamps y2038 safe
  ipc: mqueue: Replace timespec with timespec64
  ipc: Make sys_semtimedop() y2038 safe
  get rid of SYSVIPC_COMPAT on ia64
  semtimedop(): move compat to native
  shmat(2): move compat to native
  msgrcv(2), msgsnd(2): move compat to native
  ipc(2): move compat to native
  ipc: make use of compat ipc_perm helpers
  semctl(): move compat to native
  semctl(): separate all layout-dependent copyin/copyout
  msgctl(): move compat to native
  msgctl(): split the actual work from copyin/copyout
  ipc: move compat shmctl to native
  shmctl: split the work from copyin/copyout

ipc: optimize semget/shmget/msgget for lots of keys

2017-09-09T01:26:51+00:00

ipc_findkey() used to scan all objects to look for the wanted key.  This
is slow when using a high number of keys.  This change adds an rhashtable
of kern_ipc_perm objects in ipc_ids, so that one lookup cease to be O(n).

This change gives a 865% improvement of benchmark reaim.jobs_per_min on a
56 threads Intel(R) Xeon(R) CPU E5-2695 v3 @ 2.30GHz with 256G memory [1]

Other (more micro) benchmark results, by the author: On an i5 laptop, the
following loop executed right after a reboot took, without and with this
change:

    for (int i = 0, k=0x424242; i < KEYS; ++i)
        semget(k++, 1, IPC_CREAT | 0600);

                 total       total          max single  max single
   KEYS        without        with        call without   call with

      1            3.5         4.9   Âµs            3.5         4.9
     10            7.6         8.6   Âµs            3.7         4.7
     32           16.2        15.9   Âµs            4.3         5.3
    100           72.9        41.8   Âµs            3.7         4.7
   1000        5,630.0       502.0   Âµs             *           *
  10000    1,340,000.0     7,240.0   Âµs             *           *
  31900   17,600,000.0    22,200.0   Âµs             *           *

 *: unreliable measure: high variance

The duration for a lookup-only usage was obtained by the same loop once
the keys are present:

                 total       total          max single  max single
   KEYS        without        with        call without   call with

      1            2.1         2.5   Âµs            2.1         2.5
     10            4.5         4.8   Âµs            2.2         2.3
     32           13.0        10.8   Âµs            2.3         2.8
    100           82.9        25.1   Âµs             *          2.3
   1000        5,780.0       217.0   Âµs             *           *
  10000    1,470,000.0     2,520.0   Âµs             *           *
  31900   17,400,000.0     7,810.0   Âµs             *           *

Finally, executing each semget() in a new process gave, when still
summing only the durations of these syscalls:

creation:
                 total       total
   KEYS        without        with

      1            3.7         5.0   Âµs
     10           32.9        36.7   Âµs
     32          125.0       109.0   Âµs
    100          523.0       353.0   Âµs
   1000       20,300.0     3,280.0   Âµs
  10000    2,470,000.0    46,700.0   Âµs
  31900   27,800,000.0   219,000.0   Âµs

lookup-only:
                 total       total
   KEYS        without        with

      1            2.5         2.7   Âµs
     10           25.4        24.4   Âµs
     32          106.0        72.6   Âµs
    100          591.0       352.0   Âµs
   1000       22,400.0     2,250.0   Âµs
  10000    2,510,000.0    25,700.0   Âµs
  31900   28,200,000.0   115,000.0   Âµs

[1] http://lkml.kernel.org/r/20170814060507.GE23258@yexl-desktop

Link: http://lkml.kernel.org/r/20170815194954.ck32ta2z35yuzpwp@debix
Signed-off-by: Guillaume Knispel 
Reviewed-by: Marc Pardo 
Cc: Davidlohr Bueso 
Cc: Kees Cook 
Cc: Manfred Spraul 
Cc: Alexey Dobriyan 
Cc: "Eric W. Biederman" 
Cc: "Peter Zijlstra (Intel)" 
Cc: Ingo Molnar 
Cc: Sebastian Andrzej Siewior 
Cc: Serge Hallyn 
Cc: Andrey Vagin 
Cc: Guillaume Knispel 
Cc: Marc Pardo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

semctl(): move compat to native

2017-07-16T00:46:44+00:00

Signed-off-by: Al Viro

ipc: move compat shmctl to native

2017-07-16T00:46:42+00:00

Signed-off-by: Al Viro

ipc/util.h: update documentation for ipc_getref() and ipc_putref()

2017-07-12T23:26:02+00:00

Now that ipc_rcu_alloc() and ipc_rcu_free() are removed, document when
it is valid to use ipc_getref() and ipc_putref().

Link: http://lkml.kernel.org/r/20170525185107.12869-21-manfred@colorfullife.com
Signed-off-by: Manfred Spraul 
Cc: Davidlohr Bueso 
Cc: Kees Cook 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc/util: drop ipc_rcu_alloc()

2017-07-12T23:26:02+00:00

No callers remain for ipc_rcu_alloc().  Drop the function.

[manfred@colorfullife.com: Rediff because the memset was temporarily inside ipc_rcu_free()]
Link: http://lkml.kernel.org/r/20170525185107.12869-13-manfred@colorfullife.com
Signed-off-by: Kees Cook 
Signed-off-by: Manfred Spraul 
Cc: Kees Cook 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc/util: drop ipc_rcu_free()

2017-07-12T23:26:01+00:00

There are no more callers of ipc_rcu_free(), so remove it.

Link: http://lkml.kernel.org/r/20170525185107.12869-9-manfred@colorfullife.com
Signed-off-by: Kees Cook 
Signed-off-by: Manfred Spraul 
Cc: Davidlohr Bueso 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: drop non-RCU allocation

2017-07-12T23:26:01+00:00

The only users of ipc_alloc() were ipc_rcu_alloc() and the on-heap
sem_io fall-back memory.  Better to just open-code these to make things
easier to read.

[manfred@colorfullife.com: Rediff due to inclusion of memset() into ipc_rcu_alloc()]
Link: http://lkml.kernel.org/r/20170525185107.12869-5-manfred@colorfullife.com
Signed-off-by: Kees Cook 
Signed-off-by: Manfred Spraul 
Cc: Davidlohr Bueso 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: merge ipc_rcu and kern_ipc_perm

2017-07-12T23:26:01+00:00

ipc has two management structures that exist for every id:
 - struct kern_ipc_perm, it contains e.g. the permissions.
 - struct ipc_rcu, it contains the rcu head for rcu handling and the
   refcount.

The patch merges both structures.

As a bonus, we may save one cacheline, because both structures are
cacheline aligned.  In addition, it reduces the number of casts, instead
most codepaths can use container_of.

To simplify code, the ipc_rcu_alloc initializes the allocation to 0.

[manfred@colorfullife.com: really include the memset() into ipc_alloc_rcu()]
  Link: http://lkml.kernel.org/r/564f8612-0601-b267-514f-a9f650ec9b32@colorfullife.com
Link: http://lkml.kernel.org/r/20170525185107.12869-3-manfred@colorfullife.com
Signed-off-by: Manfred Spraul 
Cc: Davidlohr Bueso 
Cc: Kees Cook 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: Remove unused declaration of recompute_msgmni

2017-04-18T02:53:07+00:00

The function recompute_msgmni was removed a while ago
but it is still declared in a header file remove it.

Signed-off-by: "Eric W. Biederman"