From: Vinayak Menon <vinmenon@codeaurora.org>
To: v.narang@samsung.com, Michal Hocko <mhocko@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>,
Maninder Singh <maninder1.s@samsung.com>,
"kstewart@linuxfoundation.org" <kstewart@linuxfoundation.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"jkosina@suse.cz" <jkosina@suse.cz>,
"pombredanne@nexb.com" <pombredanne@nexb.com>,
"jpoimboe@redhat.com" <jpoimboe@redhat.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"vbabka@suse.cz" <vbabka@suse.cz>,
"guptap@codeaurora.org" <guptap@codeaurora.org>,
AMIT SAHRAWAT <a.sahrawat@samsung.com>,
PANKAJ MISHRA <pankaj.m@samsung.com>,
Lalit Mohan Tripathi <lalit.mohan@samsung.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
kasan-dev <kasan-dev@googlegroups.com>
Subject: Re: [PATCH 1/1] stackdepot: interface to check entries and size of stackdepot.
Date: Tue, 28 Nov 2017 09:07:46 +0530 [thread overview]
Message-ID: <ad4e2b97-ad94-32f7-3002-ff0cab00d3ab@codeaurora.org> (raw)
In-Reply-To: <20171124133025epcms5p7dc263c4a831552245e60193917a45b07@epcms5p7>
On 11/24/2017 7:00 PM, Vaneet Narang wrote:
> Hi Michal,
>
>>> We have been getting similar kind of such entries and eventually
>>> stackdepot reaches Max Cap. So we found this interface useful in debugging
>>> stackdepot issue so shared in community.
>
>> Then use it for internal debugging and provide a code which would scale
>> better on smaller systems. We do not need this in the kernel IMHO. We do
>> not merge all the debugging patches we use for internal development.
> `
> Not just debugging but this information can also be used to profile and tune stack depot.
> Getting count of stack entries would help in deciding hash table size and
> page order used by stackdepot.
>
> For less entries, bigger hash table and higher page order slabs might not be required as
> maintained by stackdepot. As i already mentioned smaller size hashtable can be choosen and
> similarly lower order pages can be used for slabs.
>
> If you think its useful, we can share scalable patch to configure below two values based on
> number of stack entries dynamically.
>
> #define STACK_ALLOC_ORDER 2
> #define STACK_HASH_SIZE (1L << STACK_HASH_ORDER)
It will be good if this hash table size can be tuned somehow. When CONFIG_PAGE_OWNER is enabled, we expect it to
consume significant amount of memory only when "page_owner" kernel param is set. But since PAGE_OWNER selects
STACKDEPOT, it consumes around 8MB (stack_table) on 64 bit without even a single stack being stored. This is a problem
on low RAM targets where we want to keep CONFIG_PAGE_OWNER enabled by default and for debugging enable the
feature via the kernel param.
I am not sure how feasible it is to configure it dynamically, but I think a hash_size early param and then a memblock alloc
of stack table at boot would work and help low ram devices.
Thanks,
Vinayak
prev parent reply other threads:[~2017-11-28 3:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20171122105142epcas5p173b7205da12e1fc72e16ec74c49db665@epcas5p1.samsung.com>
2017-11-22 10:47 ` [PATCH 1/1] stackdepot: interface to check entries and size of stackdepot Maninder Singh
2017-11-23 16:28 ` Michal Hocko
[not found] ` <CGME20171122105142epcas5p173b7205da12e1fc72e16ec74c49db665@epcms5p3>
2017-11-24 9:41 ` Maninder Singh
2017-11-24 9:54 ` Michal Hocko
2017-11-24 10:23 ` Dmitry Vyukov
[not found] ` <CGME20171122105142epcas5p173b7205da12e1fc72e16ec74c49db665@epcms5p4>
2017-11-24 11:57 ` Vaneet Narang
2017-11-24 12:44 ` Michal Hocko
[not found] ` <CGME20171122105142epcas5p173b7205da12e1fc72e16ec74c49db665@epcms5p7>
2017-11-24 13:30 ` Vaneet Narang
2017-11-24 13:48 ` Michal Hocko
2017-11-28 3:37 ` Vinayak Menon [this message]
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