From: Qian Cai <cai@lca.pw>
To: Michal Hocko <mhocko@kernel.org>
Cc: akpm@linux-foundation.org, Pavel.Tatashin@microsoft.com,
mingo@kernel.org, mgorman@techsingularity.net,
iamjoonsoo.kim@lge.com, tglx@linutronix.de, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] mm/page_owner: fix for deferred struct page init
Date: Thu, 3 Jan 2019 17:22:29 -0500 [thread overview]
Message-ID: <a5666d82-b7ad-4b90-5f4e-fd22afc3e1dc@lca.pw> (raw)
In-Reply-To: <20190103202235.GE31793@dhcp22.suse.cz>
On 1/3/19 3:22 PM, Michal Hocko wrote:
> On Thu 03-01-19 14:53:47, Qian Cai wrote:
>> On 1/3/19 2:07 PM, Michal Hocko wrote> So can we make the revert with an
>> explanation that the patch was wrong?
>>> If we want to make hacks to catch more objects to be tracked then it
>>> would be great to have some numbers in hands.
>>
>> Well, those numbers are subject to change depends on future start_kernel()
>> order. Right now, there are many functions could be caught earlier by page owner.
>>
>> kmemleak_init();
> [...]
>> sched_init_smp();
>
> The kernel source dump will not tell us much of course. A ball park
> number whether we are talking about dozen, hundreds or thousands of
> allocations would tell us something at least, doesn't it.
>
> Handwaving that it might help us some is not particurarly useful. We are
> already losing some allocations already. Does it matter? Well, that
> depends, sometimes we do want to catch an owner of particular page and
> it is sad to find nothing. But how many times have you or somebody else
> encountered that in practice. That is exactly a useful information to
> judge an ugly ifdefery in the code. See my point?
Here is the number without DEFERRED_STRUCT_PAGE_INIT.
== page_ext_init() after page_alloc_init_late() ==
Node 0, zone DMA: page owner found early allocated 0 pages
Node 0, zone DMA32: page owner found early allocated 7009 pages
Node 0, zone Normal: page owner found early allocated 85827 pages
Node 4, zone Normal: page owner found early allocated 75063 pages
== page_ext_init() before kmemleak_init() ==
Node 0, zone DMA: page owner found early allocated 0 pages
Node 0, zone DMA32: page owner found early allocated 6654 pages
Node 0, zone Normal: page owner found early allocated 41907 pages
Node 4, zone Normal: page owner found early allocated 41356 pages
So, it told us that it will miss tens of thousands of early page allocation call
sites.
next prev parent reply other threads:[~2019-01-03 22:22 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-18 22:31 kernel panic with page_owner=on Qian Cai
2018-12-19 1:57 ` [PATCH] mm: skip checking poison pattern for page_to_nid() Qian Cai
2018-12-19 10:20 ` Michal Hocko
2018-12-19 12:46 ` Qian Cai
2018-12-20 6:03 ` [PATCH] mm/page_owner: fix for deferred struct page init Qian Cai
2018-12-20 9:22 ` Michal Hocko
2018-12-20 18:50 ` [PATCH v2] " Qian Cai
2018-12-20 20:31 ` [PATCH v3] " Qian Cai
2018-12-20 21:00 ` William Kucharski
2018-12-20 21:04 ` Qian Cai
2018-12-20 21:04 ` Qian Cai
2019-01-03 11:51 ` Michal Hocko
2019-01-03 16:38 ` Qian Cai
2019-01-03 16:59 ` Michal Hocko
2019-01-03 17:38 ` Qian Cai
2019-01-03 19:07 ` Michal Hocko
2019-01-03 19:53 ` Qian Cai
2019-01-03 20:22 ` Michal Hocko
2019-01-03 22:22 ` Qian Cai [this message]
2019-01-04 13:09 ` Michal Hocko
2019-01-04 15:01 ` Qian Cai
2019-01-04 15:17 ` Michal Hocko
2019-01-04 15:25 ` Qian Cai
2019-01-04 15:32 ` Michal Hocko
2019-01-04 20:18 ` Qian Cai
2019-01-07 18:43 ` Michal Hocko
2019-01-08 1:53 ` Qian Cai
2019-01-08 8:20 ` Michal Hocko
2019-01-08 13:19 ` Qian Cai
2019-01-08 13:19 ` Qian Cai
2019-01-08 22:02 ` Andrew Morton
2019-01-08 22:13 ` Qian Cai
2019-01-08 22:40 ` Michal Hocko
2019-01-09 7:34 ` [PATCH v2] " Michal Hocko
2019-01-15 20:28 ` [PATCH] Revert "mm: use early_pfn_to_nid in page_ext_init" Qian Cai
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