Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: BUG: Bad page state [was: Strange oopses in 2.6.30] | Date | Tue, 23 Jun 2009 20:04:11 +0900 (JST) |
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> On Mon, Jun 22, 2009 at 11:39:53AM +0900, KOSAKI Motohiro wrote: > > (cc to Mel and some reviewer) > > > > > Flags are: > > > 0000000000400000 -- __PG_MLOCKED > > > 800000000050000c -- my page flags > > > 3650000c -- Maxim's page flags > > > 0000000000693ce1 -- my PAGE_FLAGS_CHECK_AT_FREE > > > > I guess commit da456f14d (page allocator: do not disable interrupts in > > free_page_mlock()) is a bit wrong. > > > > current code is: > > ------------------------------------------------------------- > > static void free_hot_cold_page(struct page *page, int cold) > > { > > (snip) > > int clearMlocked = PageMlocked(page); > > (snip) > > if (free_pages_check(page)) > > return; > > (snip) > > local_irq_save(flags); > > if (unlikely(clearMlocked)) > > free_page_mlock(page); > > ------------------------------------------------------------- > > > > Oh well, we remove PG_Mlocked *after* free_pages_check(). > > Then, it makes false-positive warning. > > > > Sorry, my review was also wrong. I think reverting this patch is better ;) > > > > I think a revert is way overkill. The intention of the patch is sound - > reducing the number of times interrupts are disabled. Having pages > with the PG_locked bit is now somewhat of an expected situation. I'd > prefer to go with either > > 1. Unconditionally clearing the bit with TestClearPageLocked as the > patch already posted does > 2. Removing PG_locked from the free_pages_check() > 3. Unlocking the pages as we go when an mlocked VMA is being torn town > > The patch that addresses 1 seemed ok to me. What do you think?
Yes, I've overlooked Hanns's patch. I think that is good patch. Thansk folks.
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