Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 1 Sep 2022 16:50:10 -0700
From:   Roman Gushchin <roman.gushchin@linux.dev>
To:     Suren Baghdasaryan <surenb@google.com>
Cc:     akpm@linux-foundation.org, kent.overstreet@linux.dev,
        mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org,
        mgorman@suse.de, dave@stgolabs.net, willy@infradead.org,
        liam.howlett@oracle.com, void@manifault.com, peterz@infradead.org,
        juri.lelli@redhat.com, ldufour@linux.ibm.com, peterx@redhat.com,
        david@redhat.com, axboe@kernel.dk, mcgrof@kernel.org,
        masahiroy@kernel.org, nathan@kernel.org, changbin.du@intel.com,
        ytcoode@gmail.com, vincent.guittot@linaro.org,
        dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
        bristot@redhat.com, vschneid@redhat.com, cl@linux.com,
        penberg@kernel.org, iamjoonsoo.kim@lge.com, 42.hyeyoo@gmail.com,
        glider@google.com, elver@google.com, dvyukov@google.com,
        shakeelb@google.com, songmuchun@bytedance.com, arnd@arndb.de,
        jbaron@akamai.com, rientjes@google.com, minchan@google.com,
        kaleshsingh@google.com, kernel-team@android.com,
        linux-mm@kvack.org, iommu@lists.linux.dev,
        kasan-dev@googlegroups.com, io-uring@vger.kernel.org,
        linux-arch@vger.kernel.org, xen-devel@lists.xenproject.org,
        linux-bcache@vger.kernel.org, linux-modules@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 16/30] mm: enable slab allocation tagging for kmalloc
 and friends
Message-ID: <YxFFMtvI/J3VN3pl@P9FQF9L96D.corp.robot.car>
References: <20220830214919.53220-1-surenb@google.com>
 <20220830214919.53220-17-surenb@google.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220830214919.53220-17-surenb@google.com>
Precedence: bulk

On Tue, Aug 30, 2022 at 02:49:05PM -0700, Suren Baghdasaryan wrote:
> Redefine kmalloc, krealloc, kzalloc, kcalloc, etc. to record allocations
> and deallocations done by these functions.

One particular case when this functionality might be very useful:
in the past we've seen examples (at Fb) where it was hard to understand
the difference between slab memory sizes of two different kernel versions
due to slab caches merging. Once a slab cache is merged with another large
cache, this data is pretty much lost. So I definetely see value in stats which
are independent from kmem caches.

The performance overhead is a concern here, so more data would be useful.

Thanks!