From: Dave Hansen <dave.hansen@linux.intel.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
torvalds@linux-foundation.org, kirill.shutemov@linux.intel.com,
akpm@linux-foundation.org, hannes@cmpxchg.org,
iamjoonsoo.kim@lge.com, mgorman@techsingularity.net,
tony.luck@intel.com, vbabka@suse.cz, mhocko@kernel.org,
aarcange@redhat.com, hillf.zj@alibaba-inc.com, hughd@google.com,
oleg@redhat.com, peterz@infradead.org, riel@redhat.com,
srikar@linux.vnet.ibm.com, vdavydov.dev@gmail.com,
mingo@kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, x86@kernel.org
Subject: Re: [mm 4.15-rc8] Random oopses under memory pressure.
Date: Thu, 18 Jan 2018 06:51:37 -0800 [thread overview]
Message-ID: <b02e08bb-b551-e239-6f30-1db4587850c8@linux.intel.com> (raw)
In-Reply-To: <20180118144514.njr5xdagtwzpzep6@node.shutemov.name>
On 01/18/2018 06:45 AM, Kirill A. Shutemov wrote:
> On Thu, Jan 18, 2018 at 06:38:10AM -0800, Dave Hansen wrote:
>> On 01/18/2018 05:12 AM, Kirill A. Shutemov wrote:
>>> - if (pte_page(*pvmw->pte) - pvmw->page >=
>>> - hpage_nr_pages(pvmw->page)) {
>> Is ->pte guaranteed to map a page which is within the same section as
>> pvmw->page? Otherwise, with sparsemem (non-vmemmap), the pointer
>> arithmetic won't work.
> No, it's not guaranteed. It can be arbitrary page.
>
> The arithmetic won't work because they are different "memory objects"?
No, because sections' mem_map[]s can be allocated non-contiguously.
Section 1's might be a lower virtual address than Section 0's.
They're allocated not unlike this:
mem_section[0]->section_mem_map = kmalloc(SECTION_SIZE);
mem_section[1]->section_mem_map = kmalloc(SECTION_SIZE);
...
The first pfn in section 1 and the last pfn in section 0 are adjacent
PFNs, but their 'struct page' might have virtual addresses that are TB
apart.
next prev parent reply other threads:[~2018-01-18 14:51 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <201801112311.EHI90152.FLJMQOStVHFOFO@I-love.SAKURA.ne.jp>
[not found] ` <20180111142148.GD1732@dhcp22.suse.cz>
[not found] ` <201801120131.w0C1VJUN034283@www262.sakura.ne.jp>
[not found] ` <CA+55aFx4pH4odYDfuGemm5TK-CS4E8pL_ipHCVzVBmsQkyWp1Q@mail.gmail.com>
[not found] ` <201801122022.IDI35401.VOQOFOMLFSFtHJ@I-love.SAKURA.ne.jp>
2018-01-14 11:54 ` [mm 4.15-rc7] Random oopses under memory pressure Tetsuo Handa
2018-01-15 23:05 ` Linus Torvalds
2018-01-16 1:15 ` [mm 4.15-rc8] " Tetsuo Handa
2018-01-16 2:14 ` Linus Torvalds
2018-01-16 8:06 ` Dave Hansen
2018-01-16 8:37 ` Ingo Molnar
2018-01-16 19:30 ` Linus Torvalds
2018-01-16 17:33 ` Tetsuo Handa
2018-01-16 19:34 ` Linus Torvalds
2018-01-17 11:08 ` Tetsuo Handa
2018-01-17 21:39 ` Linus Torvalds
2018-01-17 21:51 ` Linus Torvalds
2018-01-17 22:04 ` Dave Hansen
2018-01-17 22:00 ` Dave Hansen
2018-01-17 22:15 ` Linus Torvalds
2018-01-18 8:12 ` Tetsuo Handa
2018-01-18 12:25 ` Kirill A. Shutemov
2018-01-18 13:12 ` Kirill A. Shutemov
2018-01-18 14:34 ` Kirill A. Shutemov
2018-01-18 14:38 ` Dave Hansen
2018-01-18 14:45 ` Kirill A. Shutemov
2018-01-18 14:51 ` Dave Hansen [this message]
2018-01-18 16:58 ` Linus Torvalds
2018-01-18 14:45 ` Dave Hansen
2018-01-18 14:58 ` Andrea Arcangeli
2018-01-18 16:56 ` Kirill A. Shutemov
2018-01-18 17:26 ` Luck, Tony
2018-01-18 17:28 ` Linus Torvalds
2018-01-18 17:26 ` Linus Torvalds
2018-01-18 23:49 ` Kirill A. Shutemov
2018-01-19 12:55 ` Matthew Wilcox
2018-01-19 18:42 ` Linus Torvalds
2018-01-19 22:12 ` Al Viro
2018-01-19 22:53 ` Linus Torvalds
2018-01-20 2:02 ` Al Viro
2018-01-20 5:24 ` Al Viro
2018-01-20 9:38 ` Luc Van Oostenryck
2018-01-22 13:26 ` Rasmus Villemoes
2018-01-22 19:58 ` Linus Torvalds
2018-01-18 15:40 ` Kirill A. Shutemov
2018-01-18 17:22 ` Michal Hocko
2018-01-19 10:02 ` Kirill A. Shutemov
2018-01-19 10:33 ` Michal Hocko
2018-01-19 11:49 ` Kirill A. Shutemov
2018-01-19 12:07 ` Michal Hocko
2018-01-19 12:30 ` Kirill A. Shutemov
2018-01-19 2:01 ` Tetsuo Handa
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