Messages in this thread | | | Date | Sun, 15 Sep 2013 13:34:38 +0200 | From | Manfred Spraul <> | Subject | Re: [PATCH 1/2] ipc/sem.c: Race in sem_lock() |
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Hi all,
On 09/15/2013 08:09 AM, Mike Galbraith wrote: > On Sat, 2013-09-14 at 23:34 +0200, Manfred Spraul wrote: > >> The bug is probably also present in 3.10 and 3.11, but for these kernels >> is is probably simpler just to move the test of sma->complex_count after >> the spin_is_locked() test. > IMHO, your 6 patch series should go to stable as well. Scalability is > still BAD without them. Now, you've shown the lock split to be buggy. > > Logically, the whole thing should be reverted entirely in stable, or > fixed up properly. Davidlohr: Are you working on fixing the open issues?
IMHO Mike is right, especially for the 3.10 long-term kernel: Either everything in ipc/*.c must be reverted or it should be fixed properly (i.e.: cherry-pick ipc/*)
I have created bugzilla entries for all issues I'm aware of:
https://bugzilla.kernel.org/show_bug.cgi?id=61351 I sent a patch yesterday.
https://bugzilla.kernel.org/show_bug.cgi?id=61321 https://bugzilla.kernel.org/show_bug.cgi?id=61331 https://bugzilla.kernel.org/show_bug.cgi?id=61341 https://bugzilla.kernel.org/show_bug.cgi?id=61361 https://bugzilla.kernel.org/show_bug.cgi?id=61371 No patches for theses 5 bugs.
And: Given these numbers from Mike, I would hate to revert anything: On 09/15/2013 10:06 AM, Mike Galbraith wrote: > On Sun, 2013-09-15 at 08:09 +0200, Mike Galbraith wrote: > >> Humongous improvements... > (a couple sem-waitzero numbers) > > master: Cpus 64, interleave 1 delay 0: 10039494796 in 30 secs > 3.10.10: Cpus 64, interleave 1 delay 0: 129236313 in 30 secs > > (rapidly scrolling micro-font bench vs reality disclaimer) One semop() completed every 3 ns, around 600 cpu ticks per operation.
-- Manfred
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