From: Paul Mackerras <paulus@samba.org>
To: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [RFC PATCH v2 3/4] powerpc: Don't bolt the hpte in kernel_map_linear_page()
Date: Mon, 15 Apr 2013 13:50:31 +1000 [thread overview]
Message-ID: <20130415035031.GA7494@iris.ozlabs.ibm.com> (raw)
In-Reply-To: <1365733021-28912-4-git-send-email-zhong@linux.vnet.ibm.com>
On Fri, Apr 12, 2013 at 10:16:59AM +0800, Li Zhong wrote:
> It seems that in kernel_unmap_linear_page(), it only checks whether there
> is a map in the linear_map_hash_slots array, so seems we don't need bolt
> the hpte.
I don't exactly understand your rationale here, but I don't think it's
safe not to have linear mapping pages bolted. Basically, if a page
will be used in the process of calling hash_page to demand-fault an
HPTE into the hash table, then that page needs to be bolted, otherwise
we can get an infinite recursion of HPT misses. That includes all
kernel stack pages, among other things, so I think we need to leave
the HPTE_V_BOLTED in there.
Paul.
next prev parent reply other threads:[~2013-04-15 3:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-12 2:16 [RFC PATCH v2 0/4] try secondary hash before BUG in kernel_map_linear_page() Li Zhong
2013-04-12 2:16 ` [RFC PATCH v2 1/4] powerpc: Move the setting of rflags out of loop in __hash_page_huge Li Zhong
2013-04-15 6:32 ` Michael Ellerman
2013-04-15 8:17 ` Li Zhong
2013-04-12 2:16 ` [RFC PATCH v2 2/4] powerpc: Split the code trying to insert hpte repeatedly as an helper function Li Zhong
2013-04-12 2:16 ` [RFC PATCH v2 3/4] powerpc: Don't bolt the hpte in kernel_map_linear_page() Li Zhong
2013-04-15 3:50 ` Paul Mackerras [this message]
2013-04-15 6:56 ` Benjamin Herrenschmidt
2013-04-15 8:15 ` Li Zhong
2013-04-15 11:27 ` Benjamin Herrenschmidt
2013-04-16 2:51 ` Li Zhong
2013-04-12 2:17 ` [RFC PATCH v2 4/4] powerpc: Try to insert the hptes repeatedly " Li Zhong
2013-04-15 6:36 ` Michael Ellerman
2013-04-15 8:21 ` Li Zhong
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