Messages in this thread | | | Date | Fri, 31 May 2013 15:46:24 -0400 | From | Naoya Horiguchi <> | Subject | Re: [PATCH v3 2/2] migrate: add migrate_entry_wait_huge() |
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> That changelog is not suitable for a -stable patch. People who > maintain and utilize the stable trees need to know in some detail what > is the end-user impact of the patch (or, equivalently, of the bug > which the patch fixes).
OK. So, could you insert the following sentence?
On Fri, May 31, 2013 at 12:30:03PM -0700, Andrew Morton wrote: > On Tue, 28 May 2013 15:52:51 -0400 Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> wrote: > > > When we have a page fault for the address which is backed by a hugepage > > under migration, the kernel can't wait correctly and do busy looping on > > hugepage fault until the migration finishes.
As a result, users who try to kick hugepage migration (via soft offlining, for example) occasionally experience long delay or soft lockup.
Thanks, Naoya
> > This is because pte_offset_map_lock() can't get a correct migration entry > > or a correct page table lock for hugepage. > > This patch introduces migration_entry_wait_huge() to solve this. > > > > Note that the caller, hugetlb_fault(), gets the pointer to the "leaf" > > entry with huge_pte_offset() inside which all the arch-dependency of > > the page table structure are. So migration_entry_wait_huge() and > > __migration_entry_wait() are free from arch-dependency. > > > > ChangeLog v3: > > - use huge_pte_lockptr > > > > ChangeLog v2: > > - remove dup in migrate_entry_wait_huge() > > > > Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> > > Reviewed-by: Rik van Riel <riel@redhat.com> > > Cc: stable@vger.kernel.org # 2.6.35 > > That changelog is not suitable for a -stable patch. People who > maintain and utilize the stable trees need to know in some detail what > is the end-user impact of the patch (or, equivalently, of the bug > which the patch fixes).
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