Export unusable free space index via /proc/pagetypeinfo
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From: KOSAKI Motohiro on 16 Feb 2010 03:50 > On Tue, Feb 16, 2010 at 04:03:29PM +0900, KOSAKI Motohiro wrote: > > > Unusuable free space index is a measure of external fragmentation that > > > takes the allocation size into account. For the most part, the huge page > > > size will be the size of interest but not necessarily so it is exported > > > on a per-order and per-zone basis via /proc/pagetypeinfo. > > > > Hmmm.. > > /proc/pagetype have a machine unfriendly format. perhaps, some user have own ugly > > /proc/pagetype parser. It have a little risk to break userland ABI. > > > > It's very low risk. I doubt there are machine parsers of > /proc/pagetypeinfo because there are very few machine-orientated actions > that can be taken based on the information. It's more informational for > a user if they were investigating fragmentation problems. > > > I have dumb question. Why can't we use another file? > > I could. What do you suggest? I agree it's low risk. but personally I hope fragmentation ABI keep very stable because I expect some person makes userland compaction daemon. (read fragmentation index from /proc and write /proc/compact_memory if necessary). then, if possible, I hope fragmentation info have individual /proc file. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Rik van Riel on 16 Feb 2010 13:40 On 02/12/2010 07:00 AM, Mel Gorman wrote: > Unusuable free space index is a measure of external fragmentation that > takes the allocation size into account. For the most part, the huge page > size will be the size of interest but not necessarily so it is exported > on a per-order and per-zone basis via /proc/pagetypeinfo. > > The index is normally calculated as a value between 0 and 1 which is > obviously unsuitable within the kernel. Instead, the first three decimal > places are used as a value between 0 and 1000 for an integer approximation. > > Signed-off-by: Mel Gorman<mel(a)csn.ul.ie> Acked-by: Rik van Riel <riel(a)redhat.com> -- All rights reversed. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Rik van Riel on 19 Feb 2010 16:50
On 02/18/2010 01:02 PM, Mel Gorman wrote: > Unusuable free space index is a measure of external fragmentation that > takes the allocation size into account. For the most part, the huge page > size will be the size of interest but not necessarily so it is exported > on a per-order and per-zone basis via /proc/unusable_index. > > The index is a value between 0 and 1. It can be expressed as a > percentage by multiplying by 100 as documented in > Documentation/filesystems/proc.txt. > > Signed-off-by: Mel Gorman<mel(a)csn.ul.ie> Acked-by: Rik van Riel <riel(a)redhat.com> -- All rights reversed. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |