Re: [PATCH] ipc/shm: Increase the defaults for SHMALL, SHMMAX to infinity

[Manfred Spraul]

On 04/19/2014 09:10 AM, Michael Kerrisk (man-pages) wrote:
> On Sat, Apr 19, 2014 at 8:55 AM, Davidlohr Bueso <davidlohr@xxxxxx> wrote:
> > On Fri, 2014-04-18 at 11:18 +0200, Manfred Spraul wrote:
> > > Risks:
> > > - The patch breaks installations that use "take current value and increase
> > >    it a bit". [seems to exist, http://marc.info/?l=linux-mm&m=139638334330127]
> > This really scares me. The probability of occurrence is now much higher,
> > and not just theoretical. It would legitimately break userspace.
> I'm missing something. Manfred's patch doesn't actually change the
> behavior on this point does it? If the problem is more than
> theoretical, then it _already_ affects users, right? (And they would
> therefore already be working around the problem.)
The current default is 32 MB. if some increases it by 1 MB, then the 
result is 33 MB.
The new default would be ULONG_MAX. If someone increases it by 1 MB, 
then the result is 1 MB - 1 byte.

--
    Manfred
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