On Thu, 23 May 2013, Peter Zijlstra wrote: > I know all that, and its completely irrelevant to the discussion. What you said in the rest of the email seems to indicate that you still do not know that and I am repeating what I have said before here. > You now have double the amount of memory you can loose, once to actual > mlock() and once through whatever generates pinned -- if it bothers with > checking limits at all. It was already doubled which was the reason for the patch. The patch avoided the doubling that we saw and it allowed to distinguish between mlocked and pinned pages. > Where we had the guarantee that x < y; you did x := x1 + x2; which then > should result in: x1 + x2 < y, instead you did: x1 < y && x2 < y, not > the same and completely wrong. We never had that guarantee. We were accounting many pages twice in the same counter. Once for mlocking and once for pinning. Thus the problem that the patch addresses. Read the changelog? There are other sources that cause pages to be not evictable (like f.e. dirtying). Mlock accounting is not accurate in any case. The mlocked page limit is per thread which is another issue and so is the vm_pinned counter. The pages actually may be shared between many processes and the ownership of those pages is not clear. The accounting for mlock and pinning also is a bit problematic as a result. -- To unsubscribe from this list: send the line "unsubscribe trinity" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
