From: Dave Hansen <dave.hansen@intel.com>
To: Pavel Tatashin <pasha.tatashin@oracle.com>,
steven.sistare@oracle.com, daniel.m.jordan@oracle.com,
linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
kirill.shutemov@linux.intel.com, mhocko@suse.com,
linux-mm@kvack.org, dan.j.williams@intel.com, jack@suse.cz,
jglisse@redhat.com, jrdr.linux@gmail.com, bhe@redhat.com,
gregkh@linuxfoundation.org, vbabka@suse.cz,
richard.weiyang@gmail.com, rientjes@google.com, mingo@kernel.org,
osalvador@techadventures.net
Subject: Re: [PATCH v3 2/2] mm/sparse: start using sparse_init_nid(), and remove old code
Date: Mon, 2 Jul 2018 13:00:43 -0700 [thread overview]
Message-ID: <38a2629d-689c-4592-9bd7-a77ab1b2045c@intel.com> (raw)
In-Reply-To: <b227cf00-a1dd-5371-aafd-9feb332e9d02@oracle.com>
On 07/02/2018 12:54 PM, Pavel Tatashin wrote:
>
>
> On 07/02/2018 03:47 PM, Dave Hansen wrote:
>> On 07/01/2018 07:04 PM, Pavel Tatashin wrote:
>>> + for_each_present_section_nr(pnum_begin + 1, pnum_end) {
>>> + int nid = sparse_early_nid(__nr_to_section(pnum_end));
>>>
>>> + if (nid == nid_begin) {
>>> + map_count++;
>>> continue;
>>> }
>>
>>> + sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
>>> + nid_begin = nid;
>>> + pnum_begin = pnum_end;
>>> + map_count = 1;
>>> }
>>
>> Ugh, this is really hard to read. Especially because the pnum "counter"
>> is called "pnum_end".
>
> I called it pnum_end, because that is what is passed to
> sparse_init_nid(), but I see your point, and I can rename pnum_end to
> simply pnum if that will make things look better.
Could you just make it a helper that takes a beginning pnum and returns
the number of consecutive sections?
>> So, this is basically a loop that collects all of the adjacent sections
>> in a given single nid and then calls sparse_init_nid(). pnum_end in
>> this case is non-inclusive, so the sparse_init_nid() call is actually
>> for the *previous* nid that pnum_end is pointing _past_.
>>
>> This *really* needs commenting.
>
> There is a comment before sparse_init_nid() about inclusiveness:
>
> 434 /*
> 435 * Initialize sparse on a specific node. The node spans [pnum_begin, pnum_end)
> 436 * And number of present sections in this node is map_count.
> 437 */
> 438 static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
> 439 unsigned long pnum_end,
> 440 unsigned long map_count)
Which I totally missed. Could you comment the code, please?
next prev parent reply other threads:[~2018-07-02 20:00 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-02 2:04 [PATCH v3 0/2] sparse_init rewrite Pavel Tatashin
2018-07-02 2:04 ` [PATCH v3 1/2] mm/sparse: add sparse_init_nid() Pavel Tatashin
2018-07-02 2:11 ` Baoquan He
2018-07-02 2:18 ` Pavel Tatashin
2018-07-02 2:31 ` Baoquan He
2018-07-02 2:43 ` Pavel Tatashin
2018-07-02 2:53 ` Baoquan He
2018-07-02 3:03 ` Pavel Tatashin
2018-07-02 3:14 ` Baoquan He
2018-07-02 3:17 ` Baoquan He
2018-07-02 3:28 ` Pavel Tatashin
2018-07-02 3:42 ` Baoquan He
2018-07-02 2:56 ` Baoquan He
2018-07-02 3:05 ` Pavel Tatashin
2018-07-02 19:59 ` Dave Hansen
2018-07-02 20:29 ` Pavel Tatashin
2018-07-05 13:39 ` Dave Hansen
2018-07-09 14:31 ` Pavel Tatashin
2018-07-02 2:04 ` [PATCH v3 2/2] mm/sparse: start using sparse_init_nid(), and remove old code Pavel Tatashin
2018-07-02 14:04 ` Oscar Salvador
2018-07-02 19:47 ` Dave Hansen
2018-07-02 19:54 ` Pavel Tatashin
2018-07-02 20:00 ` Dave Hansen [this message]
2018-07-02 20:12 ` Pavel Tatashin
2018-07-02 16:20 ` [PATCH v3 0/2] sparse_init rewrite Dave Hansen
2018-07-02 17:46 ` Pavel Tatashin
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