Messages in this thread | | | From | Robin Getz <> | Subject | Re: [PATCH, RFD]: Unbreak no-mmu mmap | Date | Mon, 11 Jun 2007 17:08:27 -0400 |
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On Sat 9 Jun 2007 15:10, Matt Mackall pondered: > On Fri, Jun 08, 2007 at 03:53:49PM +0200, Bernd Schmidt wrote: > > 2. It is no longer possible to get blocks smaller than a page through > > mmap. This behaviour was used by simplemalloc, which is an insane > > way of implementing malloc on nommu systems and hopefully not used > > by anyone anymore. > > That's worrisome. Breaking existing apps/libraries seems like a bad > idea.
It is a bad idea - but on noMMU - breaking existing apps/libraries is (unfortunately) a pretty common thing... - the standard distribution - uClinux - rebuilds all things : kernel, apps, libc, shell, etc which run on the target - everytime you type 'make' - the standard library - uClibc - has little concept of binary compatibility, and has none in their years of releasing things. (which is OK, since everything is re-built with a simple 'make' anyway)
Plus - what Bernd talked about - uClibc's simple malloc, isn't used that often (at all that I am aware of), on any modern uClibc systems. The overhead of calling the kernel to manage memory kills performance.
As a user of the kernel in a noMMU environment - I would rather have Bernd's patch - which makes things closer to a MMU environment - and allows standard applications to work better (at all) - rather than backwards binary compatibility.
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