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From: David Hildenbrand <david@redhat.com>
To: Michal Hocko <mhocko@suse.com>, John Hubbard <jhubbard@nvidia.com>
Cc: "Suren Baghdasaryan" <surenb@google.com>,
	"Pavel Machek" <pavel@ucw.cz>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Colin Cross" <ccross@google.com>,
	"Sumit Semwal" <sumit.semwal@linaro.org>,
	"Dave Hansen" <dave.hansen@intel.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Matthew Wilcox" <willy@infradead.org>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	"Vlastimil Babka" <vbabka@suse.cz>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Al Viro" <viro@zeniv.linux.org.uk>,
	"Randy Dunlap" <rdunlap@infradead.org>,
	"Kalesh Singh" <kaleshsingh@google.com>,
	"Peter Xu" <peterx@redhat.com>,
	rppt@kernel.org, "Peter Zijlstra" <peterz@infradead.org>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	vincenzo.frascino@arm.com,
	"Chinwen Chang (張錦文)" <chinwen.chang@mediatek.com>,
	"Axel Rasmussen" <axelrasmussen@google.com>,
	"Andrea Arcangeli" <aarcange@redhat.com>,
	"Jann Horn" <jannh@google.com>,
	apopple@nvidia.com, "Yu Zhao" <yuzhao@google.com>,
	"Will Deacon" <will@kernel.org>,
	fenghua.yu@intel.com, thunder.leizhen@huawei.com,
	"Hugh Dickins" <hughd@google.com>,
	feng.tang@intel.com, "Jason Gunthorpe" <jgg@ziepe.ca>,
	"Roman Gushchin" <guro@fb.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	krisman@collabora.com, chris.hyser@oracle.com,
	"Peter Collingbourne" <pcc@google.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"Jens Axboe" <axboe@kernel.dk>,
	legion@kernel.org, "Rolf Eike Beer" <eb@emlix.com>,
	"Cyrill Gorcunov" <gorcunov@gmail.com>,
	"Muchun Song" <songmuchun@bytedance.com>,
	"Viresh Kumar" <viresh.kumar@linaro.org>,
	"Thomas Cedeno" <thomascedeno@google.com>,
	sashal@kernel.org, cxfcosmos@gmail.com,
	"Rasmus Villemoes" <linux@rasmusvillemoes.dk>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-mm <linux-mm@kvack.org>,
	kernel-team <kernel-team@android.com>
Subject: Re: [PATCH v10 3/3] mm: add anonymous vma name refcounting
Date: Wed, 6 Oct 2021 11:27:45 +0200	[thread overview]
Message-ID: <6b15c682-72eb-724d-bc43-36ae6b79b91a@redhat.com> (raw)
In-Reply-To: <YV1eCu0eZ+gQADNx@dhcp22.suse.cz>

On 06.10.21 10:27, Michal Hocko wrote:
> On Tue 05-10-21 23:57:36, John Hubbard wrote:
> [...]
>> 1) Yes, just leave the strings in the kernel, that's simple and
>> it works, and the alternatives don't really help your case nearly
>> enough.
> 
> I do not have a strong opinion. Strings are easier to use but they
> are more involved and the necessity of kref approach just underlines
> that. There are going to be new allocations and that always can lead
> to surprising side effects.  These are small (80B at maximum) so the
> overall footpring shouldn't all that large by default but it can grow
> quite large with a very high max_map_count. There are workloads which
> really require the default to be set high (e.g. heavy mremap users). So
> if anything all those should be __GFP_ACCOUNT and memcg accounted.
> 
> I do agree that numbers are just much more simpler from accounting,
> performance and implementation POV.

+1

I can understand that having a string can be quite beneficial e.g., when 
dumping mmaps. If only user space knows the id <-> string mapping, that 
can be quite tricky.

However, I also do wonder if there would be a way to standardize/reserve 
ids, such that a given id always corresponds to a specific user. If we 
use an uint64_t for an id, there would be plenty room to reserve ids ...

I'd really prefer if we can avoid using strings and instead using ids.

-- 
Thanks,

David / dhildenb


  reply	other threads:[~2021-10-06  9:27 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-01 20:56 [PATCH v10 1/3] mm: rearrange madvise code to allow for reuse Suren Baghdasaryan
2021-10-01 20:56 ` [PATCH v10 2/3] mm: add a field to store names for private anonymous memory Suren Baghdasaryan
2021-10-01 23:08   ` Andrew Morton
2021-10-02  0:52     ` Suren Baghdasaryan
2021-10-04 16:21       ` Suren Baghdasaryan
2021-10-07  2:39         ` Andrew Morton
2021-10-07  2:50           ` Suren Baghdasaryan
2021-10-01 20:56 ` [PATCH v10 3/3] mm: add anonymous vma name refcounting Suren Baghdasaryan
2021-10-05 18:42   ` Pavel Machek
2021-10-05 19:14     ` Suren Baghdasaryan
2021-10-05 19:21       ` Kees Cook
2021-10-05 20:04       ` Pavel Machek
2021-10-05 20:43         ` Suren Baghdasaryan
2021-10-06  6:57           ` John Hubbard
2021-10-06  8:27             ` Michal Hocko
2021-10-06  9:27               ` David Hildenbrand [this message]
2021-10-06 15:01                 ` Suren Baghdasaryan
2021-10-06 15:07                   ` David Hildenbrand
2021-10-06 15:20                     ` Suren Baghdasaryan
2021-10-07  2:29                       ` Andrew Morton
2021-10-07  2:46                         ` Suren Baghdasaryan
2021-10-07  2:53                           ` Andrew Morton
2021-10-07  3:01                             ` Suren Baghdasaryan
2021-10-07  7:27                               ` David Hildenbrand
2021-10-07  7:33                       ` David Hildenbrand
2021-10-07 15:42                         ` Suren Baghdasaryan
2021-10-06 17:58                   ` Pavel Machek
2021-10-06 18:18                     ` Suren Baghdasaryan
2021-10-07  8:10                       ` Michal Hocko
2021-10-07  8:41                         ` Pavel Machek
2021-10-07  8:47                         ` Rasmus Villemoes
2021-10-07 10:15                           ` Pavel Machek
2021-10-07 16:04                             ` Suren Baghdasaryan
2021-10-07 16:40                               ` Michal Hocko
2021-10-07 16:58                                 ` Suren Baghdasaryan
2021-10-07 17:31                                   ` Michal Hocko
2021-10-07 17:50                                     ` Suren Baghdasaryan
2021-10-07 18:12                                       ` Kees Cook
2021-10-07 18:50                                         ` Suren Baghdasaryan
2021-10-07 19:02                                           ` John Hubbard
2021-10-07 21:32                                             ` Suren Baghdasaryan
2021-10-08  1:04                                               ` Liam Howlett
2021-10-08  7:25                                             ` Rasmus Villemoes
2021-10-08  7:43                                               ` David Hildenbrand
2021-10-08 21:13                                                 ` Kees Cook
2021-10-08  6:34                                         ` Michal Hocko
2021-10-08 14:14                                           ` Dave Hansen
2021-10-08 14:57                                             ` Michal Hocko
2021-10-08 16:10                                               ` Suren Baghdasaryan
2021-10-08 20:58                                           ` Kees Cook
2021-10-11  8:36                                             ` Michal Hocko
2021-10-12  1:18                                               ` Suren Baghdasaryan
2021-10-12  1:20                                                 ` Suren Baghdasaryan
2021-10-12  3:00                                                   ` Johannes Weiner
2021-10-12  5:36                                                     ` Suren Baghdasaryan
2021-10-12 18:26                                                       ` Johannes Weiner
2021-10-12 18:52                                                         ` Suren Baghdasaryan
2021-10-12 20:41                                                           ` Johannes Weiner
2021-10-12 20:59                                                             ` Suren Baghdasaryan
2021-10-12  7:36                                                   ` Michal Hocko
2021-10-12 16:50                                                     ` Suren Baghdasaryan
2021-10-12  7:43                                                 ` David Hildenbrand
2021-10-12 17:01                                                   ` Suren Baghdasaryan
2021-10-14 20:16                                                     ` Suren Baghdasaryan
2021-10-15  8:03                                                       ` David Hildenbrand
2021-10-15 16:30                                                         ` Suren Baghdasaryan
2021-10-15 16:39                                                           ` David Hildenbrand
2021-10-15 18:33                                                             ` Suren Baghdasaryan
2021-10-15 17:45                                                           ` Kees Cook
2021-10-07  7:59                   ` Michal Hocko
2021-10-07 15:45                     ` Suren Baghdasaryan
2021-10-07 16:37                       ` Michal Hocko
2021-10-07 16:43                         ` Suren Baghdasaryan
2021-10-07 17:25                           ` Michal Hocko
2021-10-07 17:30                             ` Suren Baghdasaryan
2021-10-04  7:03 ` [PATCH v10 1/3] mm: rearrange madvise code to allow for reuse Rolf Eike Beer
2021-10-04 16:18   ` Suren Baghdasaryan
2021-10-05 21:00     ` Liam Howlett
2021-10-05 21:30       ` Suren Baghdasaryan
2021-10-06 17:33         ` Liam Howlett

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