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From: Jeremy F. <je...@go...> - 2004-09-08 20:41:54
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On Thu, 2004-09-02 at 08:58 +0100, Nicholas Nethercote wrote: > The big-bang shadow alloc uses PROT_NONE + MAP_PRIVATE|MAP_ANON|MAP_FIXED. > For Memcheck the alloc-size is 1.5GB. > > The stage1 padding uses PROT_NONE + MAP_FIXED|MAP_PRIVATE, with a real > file. Typically, on my machine it does two mmaps, with a combined size of > 2.8GB. > > I wonder if the use of a file causes the difference. Yes, it does. The kernel is worried about whether there's somewhere to put the dirty pages as memory fills up. If there's no file backing, then the limit is phys.mem+swap. But if the mapping is backed by a file, then that mapping doesn't need to use swap if it is paged out. J |