[PATCH] makedumpfile: Fix a bug found during regression testing for v1.5.6

[Petr Tesarik]

V Thu, 17 Apr 2014 09:27:09 +0000
Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp> napsáno:

> >On Thu, 17 Apr 2014 08:33:19 +0000
> >Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp> wrote:
> >
> >> >> From: Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp>
> >> >> Date: Wed, 16 Apr 2014 14:56:01 +0900
> >> >> Subject: [PATCH] Exclude small cycle regions wrongly.
> >> >>
> >> >> In bitmap initialization, if a cycle region is smaller than 8 pages
> >> >> and its start_pfn is aligned to multiple of 8 pages, it will be
> >> >> excluded wrongly.
> >> >>
> >> >>   Example case:
> >> >>     pfn_start=0x103ff80, pfn_start_roundup=0x103ff80
> >> >>     pfn_end=0x103ff84, pfn_end_round=0x103ff80
> >> >>
> >> >> This case doesn't meet any conditions to set bits in
> >> >> create_1st_bitmap_cyclic() and initialize_2nd_bitmap_cyclic().
> >> >> We should admit the case where pfn_start is equal to pfn_end_round
> >> >> like above.
> >> >
> >> >Hello Kumagai-san,
> >> >
> >> >FWIW I cleaned up these bit operations in makedumpfile, completely
> >> >removing this code and instead adding functions for efficient setting
> >> >and clearing of a range of bits in a bitmap:
> >> >
> >> >set_bits(char *buf, size_t start, size_t end);
> >> >clear_bits(char *buf, size_t start, size_t end);
> >> >
> >> >The whole branch is still sitting on my disk, because I based it on
> >> >my other patch series (generic handling of multi-page exclusions), and
> >> >there were quite some conflicts when I tried to rebase it on devel.
> >> >
> >> >But if you include it in v1.5.6, I will do the rebase nevertheless,
> >> >so it doesn't have to wait for your decision about the other series.
> >> >
> >> >Can we do it that way?
> >>
> >> Yes. If you can rebase your local branch on the current devel branch,
> >> reviewing them for v1.5.7 will go on smoothly.
> >
> >Hm, I'm not sure I know what to do. So, let me make a summary of my
> >local makedumpfile branches:
> >
> >1. pfn_t: introduce the mdf_pfn_t type
> >2. cycle_align: make cycle alignment unnecessary
> 
> Is this "generic handling of multi-page exclusions"?

Yes. Sorry for confusing you by using an older description here.

> >3. bitmap_ops: helpers to set/clear range of bits (not yet sent)
> >4. hugepage: handling of compound pages (not yet sent)
>[...]
> 
> Anyway, you're right. I want to merge these 4 sets into v1.5.7.

OK, I'll wait until v1.5.6 is ready.

Petr T