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;
Message-ID: <78e55029-0eaf-b4b3-7e86-1086b97c60c6@redhat.com>
Date:   Thu, 1 Sep 2022 17:07:06 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.12.0
Content-Language: en-US
To:     Kent Overstreet <kent.overstreet@linux.dev>
Cc:     Michal Hocko <mhocko@suse.com>, Mel Gorman <mgorman@suse.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Suren Baghdasaryan <surenb@google.com>,
        akpm@linux-foundation.org, vbabka@suse.cz, hannes@cmpxchg.org,
        roman.gushchin@linux.dev, dave@stgolabs.net, willy@infradead.org,
        liam.howlett@oracle.com, void@manifault.com, juri.lelli@redhat.com,
        ldufour@linux.ibm.com, peterx@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
References: <20220830214919.53220-1-surenb@google.com>
 <Yw8P8xZ4zqu121xL@hirez.programming.kicks-ass.net>
 <20220831084230.3ti3vitrzhzsu3fs@moria.home.lan>
 <20220831101948.f3etturccmp5ovkl@suse.de> <Yw88RFuBgc7yFYxA@dhcp22.suse.cz>
 <20220831190154.qdlsxfamans3ya5j@moria.home.lan>
 <404e947a-e1b2-0fae-8b4f-6f2e3ba6328d@redhat.com>
 <20220901142345.agkfp2d5lijdp6pt@moria.home.lan>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
Subject: Re: [RFC PATCH 00/30] Code tagging framework and applications
In-Reply-To: <20220901142345.agkfp2d5lijdp6pt@moria.home.lan>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 01.09.22 16:23, Kent Overstreet wrote:
> On Thu, Sep 01, 2022 at 10:05:03AM +0200, David Hildenbrand wrote:
>> On 31.08.22 21:01, Kent Overstreet wrote:
>>> On Wed, Aug 31, 2022 at 12:47:32PM +0200, Michal Hocko wrote:
>>>> On Wed 31-08-22 11:19:48, Mel Gorman wrote:
>>>>> Whatever asking for an explanation as to why equivalent functionality
>>>>> cannot not be created from ftrace/kprobe/eBPF/whatever is reasonable.
>>>>
>>>> Fully agreed and this is especially true for a change this size
>>>> 77 files changed, 3406 insertions(+), 703 deletions(-)
>>>
>>> In the case of memory allocation accounting, you flat cannot do this with ftrace
>>> - you could maybe do a janky version that isn't fully accurate, much slower,
>>> more complicated for the developer to understand and debug and more complicated
>>> for the end user.
>>>
>>> But please, I invite anyone who's actually been doing this with ftrace to
>>> demonstrate otherwise.
>>>
>>> Ftrace just isn't the right tool for the job here - we're talking about adding
>>> per callsite accounting to some of the fastest fast paths in the kernel.
>>>
>>> And the size of the changes for memory allocation accounting are much more
>>> reasonable:
>>>  33 files changed, 623 insertions(+), 99 deletions(-)
>>>
>>> The code tagging library should exist anyways, it's been open coded half a dozen
>>> times in the kernel already.
>>
>> Hi Kent,
>>
>> independent of the other discussions, if it's open coded already, does
>> it make sense to factor that already-open-coded part out independently
>> of the remainder of the full series here?
> 
> It's discussed in the cover letter, that is exactly how the patch series is
> structured.

Skimming over the patches (that I was CCed on) and skimming over the
cover letter, I got the impression that everything after patch 7 is
introducing something new instead of refactoring something out.

>  
>> [I didn't immediately spot if this series also attempts already to
>> replace that open-coded part]
> 
> Uh huh.
> 
> Honestly, some days it feels like lkml is just as bad as slashdot, with people
> wanting to get in their two cents without actually reading...

... and of course you had to reply like that. I should just have learned
from my last upstream experience with you and kept you on my spam list.

Thanks, bye

-- 
Thanks,

David / dhildenb