Documentation: correct overcommit caveat in hugetlbpage.txt
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PATCH 1/1 Documentation: correct overcommit caveat in hugetlbpage.txt
As shown by Gurudas Pai recently, we can put hugepages into the surplus state (by echo 0 > /proc/sys/vm/nr_hugepages), even when /proc/sys/vm/nr_overcommit_hugepages is 0. This is actually correct, to allow the original goal (shrink the static pool to 0) to succeed (we are converting hugepages to surplus because they are in use). However, the documentation does not accurately reflect this case. Update it.
Signed-off-by Nishanth Aravamudan <[email protected]>
Acked-by Andy Whitcroft <[email protected]>
Documentation/vm/hugetlbpage.txt +3 -4
@@ -88,10 +88,9 @@ hugepages from the buddy allocator, if the normal pool is exhausted. As these surplus hugepages go out of use, they are freed back to the buddy allocator. -Caveat: Shrinking the pool via nr_hugepages while a surplus is in effect -will allow the number of surplus huge pages to exceed the overcommit -value, as the pool hugepages (which must have been in use for a surplus -hugepages to be allocated) will become surplus hugepages. As long as +Caveat: Shrinking the pool via nr_hugepages such that it becomes less +than the number of hugepages in use will convert the balance to surplus +huge pages even if it would exceed the overcommit value. As long as this condition holds, however, no more surplus huge pages will be allowed on the system until one of the two sysctls are increased sufficiently, or the surplus huge pages go out of use and are freed.
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Nishanth Aravamudan <[email protected]> IBM Linux Technology Center -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to [email protected]. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"[email protected]"> [email protected] </a>