From: Andrew Morton <akpm@linux-foundation.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: kent.overstreet@linux.dev, corbet@lwn.net, arnd@arndb.de,
mcgrof@kernel.org, rppt@kernel.org, paulmck@kernel.org,
thuth@redhat.com, tglx@linutronix.de, bp@alien8.de,
xiongwei.song@windriver.com, ardb@kernel.org, david@redhat.com,
vbabka@suse.cz, mhocko@suse.com, hannes@cmpxchg.org,
roman.gushchin@linux.dev, dave@stgolabs.net, willy@infradead.org,
liam.howlett@oracle.com, pasha.tatashin@soleen.com,
souravpanda@google.com, keescook@chromium.org, dennis@kernel.org,
jhubbard@nvidia.com, yuzhao@google.com, vvvvvv@google.com,
rostedt@goodmis.org, iamjoonsoo.kim@lge.com, rientjes@google.com,
minchan@google.com, kaleshsingh@google.com,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org,
linux-modules@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH v2 5/6] alloc_tag: make page allocation tag reference size configurable
Date: Sun, 1 Sep 2024 22:09:31 -0700 [thread overview]
Message-ID: <20240901220931.53d3ad335ae9ac3fe7ef3928@linux-foundation.org> (raw)
In-Reply-To: <20240902044128.664075-6-surenb@google.com>
On Sun, 1 Sep 2024 21:41:27 -0700 Suren Baghdasaryan <surenb@google.com> wrote:
> Introduce CONFIG_PGALLOC_TAG_REF_BITS to control the size of the
> page allocation tag references. When the size is configured to be
> less than a direct pointer, the tags are searched using an index
> stored as the tag reference.
>
> ...
>
> +config PGALLOC_TAG_REF_BITS
> + int "Number of bits for page allocation tag reference (10-64)"
> + range 10 64
> + default "64"
> + depends on MEM_ALLOC_PROFILING
> + help
> + Number of bits used to encode a page allocation tag reference.
> +
> + Smaller number results in less memory overhead but limits the number of
> + allocations which can be tagged (including allocations from modules).
> +
In other words, "we have no idea what's best for you, you're on your
own".
I pity our poor users.
Can we at least tell them what they should look at to determine whether
whatever random number they chose was helpful or harmful?
next prev parent reply other threads:[~2024-09-02 5:09 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-02 4:41 [PATCH v2 0/6] page allocation tag compression Suren Baghdasaryan
2024-09-02 4:41 ` [PATCH v2 1/6] maple_tree: add mas_for_each_rev() helper Suren Baghdasaryan
2024-09-02 4:41 ` [PATCH v2 2/6] alloc_tag: load module tags into separate continuous memory Suren Baghdasaryan
2024-09-02 4:41 ` [PATCH v2 3/6] alloc_tag: eliminate alloc_tag_ref_set Suren Baghdasaryan
2024-09-02 4:41 ` [PATCH v2 4/6] alloc_tag: introduce pgalloc_tag_ref to abstract page tag references Suren Baghdasaryan
2024-09-02 4:41 ` [PATCH v2 5/6] alloc_tag: make page allocation tag reference size configurable Suren Baghdasaryan
2024-09-02 5:09 ` Andrew Morton [this message]
2024-09-04 1:07 ` Suren Baghdasaryan
2024-09-04 1:16 ` Kent Overstreet
2024-09-04 2:04 ` Suren Baghdasaryan
2024-09-04 16:25 ` Kent Overstreet
2024-09-04 16:35 ` Suren Baghdasaryan
2024-09-02 4:41 ` [PATCH v2 6/6] alloc_tag: config to store page allocation tag refs in page flags Suren Baghdasaryan
2024-09-02 5:16 ` Andrew Morton
2024-09-03 18:19 ` Suren Baghdasaryan
2024-09-04 1:25 ` John Hubbard
2024-09-04 2:05 ` John Hubbard
2024-09-04 16:08 ` Suren Baghdasaryan
2024-09-04 18:58 ` John Hubbard
2024-09-04 21:07 ` Suren Baghdasaryan
2024-09-04 2:18 ` Matthew Wilcox
2024-09-04 16:18 ` Suren Baghdasaryan
2024-09-04 16:21 ` Kent Overstreet
2024-09-04 16:35 ` Matthew Wilcox
2024-09-04 16:37 ` Kent Overstreet
2024-09-04 16:39 ` Suren Baghdasaryan
2024-09-04 2:41 ` Kent Overstreet
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