From: Pavel Tatashin <pasha.tatashin@oracle.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Steven Sistare <steven.sistare@oracle.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
LKML <linux-kernel@vger.kernel.org>,
kirill.shutemov@linux.intel.com, Michal Hocko <mhocko@suse.com>,
Linux Memory Management List <linux-mm@kvack.org>,
dan.j.williams@intel.com, jack@suse.cz, jglisse@redhat.com,
Souptick Joarder <jrdr.linux@gmail.com>,
bhe@redhat.com, gregkh@linuxfoundation.org,
Vlastimil Babka <vbabka@suse.cz>,
Wei Yang <richard.weiyang@gmail.com>,
dave.hansen@intel.com, rientjes@google.com, mingo@kernel.org,
osalvador@techadventures.net, abdhalee@linux.vnet.ibm.com,
mpe@ellerman.id.au
Subject: Re: [PATCH 2/3] mm: calculate deferred pages after skipping mirrored memory
Date: Tue, 24 Jul 2018 21:19:11 -0400 [thread overview]
Message-ID: <CAGM2reb9CLpq1cqPLVqYXEfUqBtCt4V0OL_F=CKCyJXqV88NcQ@mail.gmail.com> (raw)
In-Reply-To: <20180724181218.13a1ed1d7a3e9a37e35707a9@linux-foundation.org>
On Tue, Jul 24, 2018 at 9:12 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Tue, 24 Jul 2018 19:55:19 -0400 Pavel Tatashin <pasha.tatashin@oracle.com> wrote:
>
> > update_defer_init() should be called only when struct page is about to be
> > initialized. Because it counts number of initialized struct pages, but
> > there we may skip struct pages if there is some mirrored memory.
>
> What are the runtime effects of this error?
I found this bug by reading the code. The effect is that fewer than
expected struct pages are initialized early in boot, and it is
possible that in some corner cases we may fail to boot when mirrored
pages are used. The deferred on demand code should somewhat mitigate
this. But, this still brings some inconsistencies compared to when
booting without mirrored pages, so it is better to fix.
Pavel
next prev parent reply other threads:[~2018-07-25 1:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-24 23:55 [PATCH 0/3] memmap_init_zone improvements Pavel Tatashin
2018-07-24 23:55 ` [PATCH 1/3] mm: make memmap_init a proper function Pavel Tatashin
2018-07-26 7:50 ` Oscar Salvador
2018-07-24 23:55 ` [PATCH 2/3] mm: calculate deferred pages after skipping mirrored memory Pavel Tatashin
2018-07-25 1:12 ` Andrew Morton
2018-07-25 1:19 ` Pavel Tatashin [this message]
2018-07-25 1:31 ` Andrew Morton
2018-07-25 1:46 ` Pavel Tatashin
2018-07-25 21:30 ` Andrew Morton
2018-07-26 15:39 ` Pavel Tatashin
2018-07-25 12:14 ` Oscar Salvador
2018-07-25 13:32 ` Pavel Tatashin
2018-07-24 23:55 ` [PATCH 3/3] mm: move mirrored memory specific code outside of memmap_init_zone Pavel Tatashin
2018-07-25 1:18 ` Andrew Morton
2018-07-25 1:31 ` Pavel Tatashin
2018-07-25 11:48 ` Oscar Salvador
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