From: Baoquan He <bhe@redhat.com>
To: Mike Rapoport <rppt@kernel.org>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org, x86@kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/6] mm/mm_init.c: remove meaningless calculation of zone->managed_pages in free_area_init_core()
Date: Wed, 20 Mar 2024 16:18:18 +0800 [thread overview]
Message-ID: <ZfqbygfNmFKpBCfR@MiWiFi-R3L-srv> (raw)
In-Reply-To: <Zfm6gzhKUehLwM5-@kernel.org>
On 03/19/24 at 06:17pm, Mike Rapoport wrote:
> On Mon, Mar 18, 2024 at 10:21:36PM +0800, Baoquan He wrote:
> > Currently, in free_area_init_core(), when initialize zone's field, a
> > rough value is set to zone->managed_pages. That value is calculated by
> > (zone->present_pages - memmap_pages).
> >
> > In the meantime, add the value to nr_all_pages and nr_kernel_pages which
> > represent all free pages of system (only low memory or including HIGHMEM
> > memory separately). Both of them are gonna be used in
> > alloc_large_system_hash().
> >
> > However, the rough calculation and setting of zone->managed_pages is
> > meaningless because
> > a) memmap pages are allocated on units of node in sparse_init() or
> > alloc_node_mem_map(pgdat); The simple (zone->present_pages -
> > memmap_pages) is too rough to make sense for zone;
> > b) the set zone->managed_pages will be zeroed out and reset with
> > acutal value in mem_init() via memblock_free_all(). Before the
> > resetting, no buddy allocation request is issued.
> >
> > Here, remove the meaningless and complicated calculation of
> > (zone->present_pages - memmap_pages), directly set zone->present_pages to
> > zone->managed_pages. It will be adjusted in mem_init().
>
> Do you mean "set zone->managed_pages to zone->present_pages"?
Hmm, maybe 'set zone->managed_pages as zone->present_pages'
or
'assign zone->present_pages to zone->managed_pages'
which is more precise.
Wwill update.
>
> I think we can just set zone->managed_pages to 0 in free_area_init_core().
> Anyway it will be reset before the first use.
Yeah, setting to 0 is also fine. I thougt of 0 ever. Considering
zone->present_pages is closer value to actual zone->managed_pages
than 0, and it may be needed in the future in some way before
mem_init(). If no strong objection, I will keep the assigning
'zone->present_pages' to 'zone->managed_pages'.
Thanks again for careful reviewing.
next prev parent reply other threads:[~2024-03-20 8:19 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-18 14:21 [PATCH 0/6] mm/mm_init.c: refactor free_area_init_core() Baoquan He
2024-03-18 14:21 ` [PATCH 1/6] mm/mm_init.c: remove the useless dma_reserve Baoquan He
2024-03-18 14:21 ` [PATCH 2/6] x86: remove memblock_find_dma_reserve() Baoquan He
2024-03-19 15:49 ` Mike Rapoport
2024-03-20 7:52 ` Baoquan He
2024-03-20 9:36 ` Mike Rapoport
2024-03-20 13:14 ` Baoquan He
2024-03-18 14:21 ` [PATCH 3/6] mm/mm_init.c: add new function calc_nr_kernel_pages() Baoquan He
2024-03-18 14:21 ` [PATCH 4/6] mm/mm_init.c: remove meaningless calculation of zone->managed_pages in free_area_init_core() Baoquan He
2024-03-19 16:17 ` Mike Rapoport
2024-03-20 8:18 ` Baoquan He [this message]
2024-03-20 8:47 ` Baoquan He
2024-03-18 14:21 ` [PATCH 5/6] mm/mm_init.c: remove unneeded calc_memmap_size() Baoquan He
2024-03-18 14:21 ` [PATCH 6/6] mm/mm_init.c: remove arch_reserved_kernel_pages() Baoquan He
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZfqbygfNmFKpBCfR@MiWiFi-R3L-srv \
--to=bhe@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=rppt@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).