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From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Michal Hocko <mhocko@kernel.org>,
	Wei Yang <richardw.yang@linux.intel.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, rientjes@google.com
Subject: Re: [Patch v2 3/4] mm/page_alloc.c: pass all bad reasons to bad_page()
Date: Tue, 21 Jan 2020 11:38:29 +0530	[thread overview]
Message-ID: <2288c80c-42f7-a161-58cf-47cf07699202@arm.com> (raw)
In-Reply-To: <20200120102200.GW18451@dhcp22.suse.cz>



On 01/20/2020 03:52 PM, Michal Hocko wrote:
> On Mon 20-01-20 11:04:14, Wei Yang wrote:
>> Now we can pass all bad reasons to __dump_page().
> And we do we want to do that? The dump of the page will tell us the
> whole story so a single and the most important reason sounds like a
> better implementation. The code is also more subtle because each caller
> of the function has to be aware of how many reasons there might be.
> Not to mention that you need a room for 5 pointers on the stack and this
> and page allocator might be called from deeper call chains.
> 

Two paths which lead to __dump_page(), dump_page() and bad_page().
Callers of dump_page() can give a single reason what they consider the
most important which leads to page dumping. This makes sense but gets
trickier in bad_page() path. At present, free_pages_check_bad() and
check_new_page_bad() has a sequence of 'if' statements which decides
"most important" reason for __dump_page() without much rationale and
similar in case of free_tail_pages_check() as well. As all information
about the page for corresponding reasons are printed with __dump_page()
anyways, do free_pages_check_bad() or check_new_page_bad() really need
to provide any particular single reason ?

  parent reply	other threads:[~2020-01-21  6:07 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-20  3:04 [Patch v2 0/4] mm/page_alloc.c: cleanup on check page Wei Yang
2020-01-20  3:04 ` [Patch v2 1/4] mm: enable dump several reasons for __dump_page() Wei Yang
2020-01-20  6:12   ` Anshuman Khandual
2020-01-20  8:55     ` Wei Yang
2020-01-21  5:20       ` Anshuman Khandual
2020-01-22  0:58         ` Wei Yang
2020-01-26  2:44         ` Wei Yang
2020-01-20  3:04 ` [Patch v2 2/4] mm/page_alloc.c: bad_[reason|flags] is not necessary when PageHWPoison Wei Yang
2020-01-20  6:28   ` Anshuman Khandual
2020-01-20 12:13     ` Wei Yang
2020-01-20 10:17   ` Michal Hocko
2020-01-20 12:20   ` David Hildenbrand
2020-01-20  3:04 ` [Patch v2 3/4] mm/page_alloc.c: pass all bad reasons to bad_page() Wei Yang
2020-01-20  6:33   ` Anshuman Khandual
2020-01-20 12:33     ` Wei Yang
2020-01-20 10:22   ` Michal Hocko
2020-01-20 12:19     ` David Hildenbrand
2020-01-21  1:49       ` Wei Yang
2020-01-21  6:08     ` Anshuman Khandual [this message]
2020-01-21  8:47       ` Michal Hocko
2020-01-20  3:04 ` [Patch v2 4/4] mm/page_alloc.c: extract commom part to check page Wei Yang
2020-01-20  6:43   ` Anshuman Khandual
2020-01-20 12:36     ` Wei Yang
2020-01-21  4:49       ` Anshuman Khandual
2020-01-22  1:00         ` Wei Yang

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