Commit c460bec7 authored by Committed by Linus Torvalds
sparc64: Eliminate PTE table memory wastage.
We've split up the PTE tables so that they take up half a page instead of a full page. This is in order to facilitate transparent huge page support, which works much better if our PMDs cover 4MB instead of 8MB. What we do is have a one-behind cache for PTE table allocations in the mm struct. This logic triggers only on allocations. For example, we don't try to keep track of free'd up page table blocks in the style that the s390 port does. There were only two slightly annoying aspects to this change: 1) Changing pgtable_t to be a "pte_t *". There's all of this special logic in the TLB free paths that needed adjustments, as did the PMD populate interfaces. 2) init_new_context() needs to zap the pointer, since the mm struct just gets copied from the parent on fork. Signed-off-by: David S. Miller <firstname.lastname@example.org> Cc: Andrea Arcangeli <email@example.com> Cc: Johannes Weiner <firstname.lastname@example.org> Cc: Gerald Schaefer <email@example.com> Signed-off-by: Andrew Morton <firstname.lastname@example.org> Signed-off-by: Linus Torvalds <email@example.com>
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