diff options
author | Hugh Dickins <hugh@veritas.com> | 2005-04-19 13:29:15 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org.(none)> | 2005-04-19 13:29:15 -0700 |
commit | e0da382c92626ad1d7f4b7527d19b80104d67a83 (patch) | |
tree | b3f455518c286ee14cb2755ced8808487bca7911 /arch/ia64 | |
parent | 9f6c6fc505560465be0964eb4da1b6ca97bd3951 (diff) |
[PATCH] freepgt: free_pgtables use vma list
Recent woes with some arches needing their own pgd_addr_end macro; and 4-level
clear_page_range regression since 2.6.10's clear_page_tables; and its
long-standing well-known inefficiency in searching throughout the higher-level
page tables for those few entries to clear and free: all can be blamed on
ignoring the list of vmas when we free page tables.
Replace exit_mmap's clear_page_range of the total user address space by
free_pgtables operating on the mm's vma list; unmap_region use it in the same
way, giving floor and ceiling beyond which it may not free tables. This
brings lmbench fork/exec/sh numbers back to 2.6.10 (unless preempt is enabled,
in which case latency fixes spoil unmap_vmas throughput).
Beware: the do_mmap_pgoff driver failure case must now use unmap_region
instead of zap_page_range, since a page table might have been allocated, and
can only be freed while it is touched by some vma.
Move free_pgtables from mmap.c to memory.c, where its lower levels are adapted
from the clear_page_range levels. (Most of free_pgtables' old code was
actually for a non-existent case, prev not properly set up, dating from before
hch gave us split_vma.) Pass mmu_gather** in the public interfaces, since we
might want to add latency lockdrops later; but no attempt to do so yet, going
by vma should itself reduce latency.
But what if is_hugepage_only_range? Those ia64 and ppc64 cases need careful
examination: put that off until a later patch of the series.
What of x86_64's 32bit vdso page __map_syscall32 maps outside any vma?
And the range to sparc64's flush_tlb_pgtables? It's less clear to me now that
we need to do more than is done here - every PMD_SIZE ever occupied will be
flushed, do we really have to flush every PGDIR_SIZE ever partially occupied?
A shame to complicate it unnecessarily.
Special thanks to David Miller for time spent repairing my ceilings.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/ia64')
-rw-r--r-- | arch/ia64/mm/hugetlbpage.c | 37 |
1 files changed, 2 insertions, 35 deletions
diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c index 40ad8328ffd5..626258ae9742 100644 --- a/arch/ia64/mm/hugetlbpage.c +++ b/arch/ia64/mm/hugetlbpage.c @@ -187,45 +187,12 @@ follow_huge_pmd(struct mm_struct *mm, unsigned long address, pmd_t *pmd, int wri } /* - * Same as generic free_pgtables(), except constant PGDIR_* and pgd_offset - * are hugetlb region specific. + * Do nothing, until we've worked out what to do! To allow build, we + * must remove reference to clear_page_range since it no longer exists. */ void hugetlb_free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *prev, unsigned long start, unsigned long end) { - unsigned long first = start & HUGETLB_PGDIR_MASK; - unsigned long last = end + HUGETLB_PGDIR_SIZE - 1; - struct mm_struct *mm = tlb->mm; - - if (!prev) { - prev = mm->mmap; - if (!prev) - goto no_mmaps; - if (prev->vm_end > start) { - if (last > prev->vm_start) - last = prev->vm_start; - goto no_mmaps; - } - } - for (;;) { - struct vm_area_struct *next = prev->vm_next; - - if (next) { - if (next->vm_start < start) { - prev = next; - continue; - } - if (last > next->vm_start) - last = next->vm_start; - } - if (prev->vm_end > first) - first = prev->vm_end; - break; - } -no_mmaps: - if (last < first) /* for arches with discontiguous pgd indices */ - return; - clear_page_range(tlb, first, last); } void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, unsigned long end) |