mm: revert 0def08e3
("mm/mempolicy.c: check return code of check_range")
Revert commit 0def08e3ac
because check_range can't fail in
migrate_to_node with considering current usecases.
Quote from Johannes
: I think it makes sense to revert. Not because of the semantics, but I
: just don't see how check_range() could even fail for this callsite:
:
: 1. we pass mm->mmap->vm_start in there, so we should not fail due to
: find_vma()
:
: 2. we pass MPOL_MF_DISCONTIG_OK, so the discontig checks do not apply
: and so can not fail
:
: 3. we pass MPOL_MF_MOVE | MPOL_MF_MOVE_ALL, the page table loops will
: continue until addr == end, so we never fail with -EIO
And I added a new VM_BUG_ON for checking migrate_to_node's future usecase
which might pass to MPOL_MF_STRICT.
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vasiliy Kulikov <segooon@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
6bdb913f0a
commit
082708072a
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@ -946,15 +946,18 @@ static int migrate_to_node(struct mm_struct *mm, int source, int dest,
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nodemask_t nmask;
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nodemask_t nmask;
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LIST_HEAD(pagelist);
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LIST_HEAD(pagelist);
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int err = 0;
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int err = 0;
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struct vm_area_struct *vma;
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nodes_clear(nmask);
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nodes_clear(nmask);
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node_set(source, nmask);
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node_set(source, nmask);
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vma = check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
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/*
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* This does not "check" the range but isolates all pages that
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* need migration. Between passing in the full user address
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* space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
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*/
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VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
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check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
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flags | MPOL_MF_DISCONTIG_OK, &pagelist);
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flags | MPOL_MF_DISCONTIG_OK, &pagelist);
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if (IS_ERR(vma))
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return PTR_ERR(vma);
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if (!list_empty(&pagelist)) {
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if (!list_empty(&pagelist)) {
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err = migrate_pages(&pagelist, new_node_page, dest,
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err = migrate_pages(&pagelist, new_node_page, dest,
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