linux-kernel - Re: [PATCH 1/2 v3] kdump: add the vmcoreinfo documentation

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Message-ID: <20181218114118.GE7485@zn.tnic>
Date:   Tue, 18 Dec 2018 12:41:18 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     lijiang <lijiang@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kexec@...ts.infradead.org,
        tglx@...utronix.de, mingo@...hat.com, x86@...nel.org,
        akpm@...ux-foundation.org, bhe@...hat.com, dyoung@...hat.com,
        linux-doc@...r.kernel.org
Subject: Re: [PATCH 1/2 v3] kdump: add the vmcoreinfo documentation

On Tue, Dec 18, 2018 at 03:31:32PM +0800, lijiang wrote:
> The printk_log is used to output human readable text, it will encapsulate header
> information for log_buf, such as timestamp, syslog level, etc.

Me asking those questions is supposed to hint that the explanations need
improvement. But you get the idea...

> >> +PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|
> >> +PG_hwpoision|PG_head_mask
> >> +=====================================================
> >> +It means the attribute of a page. These flags will be used to filter
> >> +the free pages.
> >> +
> >> +PAGE_BUDDY_MAPCOUNT_VALUE or ~PG_buddy
> >> +======================================
> >> +The 'PG_buddy' flag indicates that the page is free and in the buddy
> >> +system. Makedumpfile can exclude the free pages managed by a buddy.
> > 
> > That text belongs with the one above?
> > 
> It exported the value of (~PG_buddy), so it is placed here independently.

Then make that obvious in the description. The one above talks about the
PG flags and this one should talk about PAGE_BUDDY_MAPCOUNT_VALUE and
what it is used for. The fact that it is computed by negating PG_buddy
is an implementation detail.

> These two variables are somewhat similar, but they are used in
> different scenarios.

Those different scenarious need to be part of the description.

> >> +KERNEL_IMAGE_SIZE
> >> +=================
> >> +The size of 'KERNEL_IMAGE_SIZE', currently unused.
> > 
> > So remove?
> > 
> 
> I'm not sure whether it should be removed, so i keep it.

If it is unused, it should be removed as an VMCOREINFO export and from
the docs. But that can be done later, as a separate patch.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.