From: Qian Cai <cai@lca.pw>
To: Anshuman Khandual <Anshuman.Khandual@arm.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Dan Williams <dan.j.williams@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Michal Hocko <mhocko@kernel.org>,
Mark Rutland <Mark.Rutland@arm.com>,
Mark Brown <broonie@kernel.org>,
Steven Price <Steven.Price@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Kees Cook <keescook@chromium.org>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Matthew Wilcox <willy@infradead.org>,
Sri Krishna chowdary <schowdary@nvidia.com>,
Dave Hansen <dave.hansen@intel.com>,
Russell King - ARM Linux <linux@armlinux.org.uk>,
Michael Ellerman <mpe@ellerman.id.au>,
Paul Mackerras <paulus@samba.org>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
"David S. Miller" <davem@davemloft.net>,
Vineet Gupta <vgupta@synopsys.com>,
James Hogan <jhogan@kernel.org>,
Paul Burton <paul.burton@mips.com>,
Ralf Baechle <ralf@linux-mips.org>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Ingo Molnar <mingo@kernel.org>,
linux-snps-arc@lists.infradead.org, linux-mips@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V12] mm/debug: Add tests validating architecture page table helpers
Date: Mon, 27 Jan 2020 21:11:53 -0500 [thread overview]
Message-ID: <14882A91-17DE-4ABD-ABF2-08E7CCEDF660@lca.pw> (raw)
In-Reply-To: <1580174873-18117-1-git-send-email-anshuman.khandual@arm.com>
> On Jan 27, 2020, at 8:28 PM, Anshuman Khandual <Anshuman.Khandual@arm.com> wrote:
>
> This adds tests which will validate architecture page table helpers and
> other accessors in their compliance with expected generic MM semantics.
> This will help various architectures in validating changes to existing
> page table helpers or addition of new ones.
>
> This test covers basic page table entry transformations including but not
> limited to old, young, dirty, clean, write, write protect etc at various
> level along with populating intermediate entries with next page table page
> and validating them.
>
> Test page table pages are allocated from system memory with required size
> and alignments. The mapped pfns at page table levels are derived from a
> real pfn representing a valid kernel text symbol. This test gets called
> right after page_alloc_init_late().
>
> This gets build and run when CONFIG_DEBUG_VM_PGTABLE is selected along with
> CONFIG_VM_DEBUG. Architectures willing to subscribe this test also need to
> select CONFIG_ARCH_HAS_DEBUG_VM_PGTABLE which for now is limited to x86 and
> arm64. Going forward, other architectures too can enable this after fixing
> build or runtime problems (if any) with their page table helpers.
What’s the value of this block of new code? It only supports x86 and arm64 which are supposed to be good now. Did those tests ever find any regression or this is almost only useful for new architectures which only happened once in a few years? The worry if not many people will use this config and code those that much in the future because it is inefficient to find bugs, it will simply be rotten like a few other debugging options out there we have in the mainline that will be a pain to remove later on.
next prev parent reply other threads:[~2020-01-28 2:11 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 1:27 [PATCH V12] mm/debug: Add tests validating architecture page table helpers Anshuman Khandual
2020-01-28 2:11 ` Qian Cai [this message]
2020-01-28 3:06 ` Anshuman Khandual
2020-01-28 3:33 ` Qian Cai
2020-01-28 4:57 ` Anshuman Khandual
2020-01-28 5:48 ` Qian Cai
2020-01-28 6:17 ` Christophe Leroy
2020-01-28 6:36 ` Qian Cai
2020-01-28 7:03 ` Anshuman Khandual
2020-01-28 7:07 ` Qian Cai
2020-01-28 6:13 ` Christophe Leroy
2020-01-28 7:12 ` Qian Cai
2020-01-28 11:58 ` Mark Brown
2020-01-28 12:09 ` Mike Rapoport
2020-01-29 22:20 ` Gerald Schaefer
2020-01-30 7:27 ` Mike Rapoport
2020-01-30 13:32 ` Anshuman Khandual
2020-01-28 17:47 ` Catalin Marinas
2020-01-28 19:07 ` Qian Cai
2020-01-29 10:36 ` Catalin Marinas
2020-01-29 11:09 ` Qian Cai
2020-01-28 17:05 ` Christophe Leroy
2020-01-30 13:04 ` Anshuman Khandual
2020-01-30 14:13 ` Christophe Leroy
2020-02-02 7:18 ` Anshuman Khandual
2020-02-02 8:31 ` Christophe Leroy
2020-02-02 11:26 ` Qian Cai
2020-02-03 15:14 ` Christophe Leroy
2020-02-03 15:48 ` Qian Cai
2020-02-02 8:26 ` Anshuman Khandual
2020-01-29 22:20 ` Gerald Schaefer
2020-01-30 13:11 ` Anshuman Khandual
2020-01-30 15:06 ` Anshuman Khandual
2020-02-10 15:37 ` Catalin Marinas
2020-02-12 9:42 ` Anshuman Khandual
2020-02-12 17:55 ` Gerald Schaefer
2020-02-13 2:15 ` Anshuman Khandual
2020-01-28 12:30 Qian Cai
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=14882A91-17DE-4ABD-ABF2-08E7CCEDF660@lca.pw \
--to=cai@lca.pw \
--cc=Anshuman.Khandual@arm.com \
--cc=Mark.Rutland@arm.com \
--cc=Steven.Price@arm.com \
--cc=akpm@linux-foundation.org \
--cc=ard.biesheuvel@linaro.org \
--cc=broonie@kernel.org \
--cc=christophe.leroy@c-s.fr \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@intel.com \
--cc=davem@davemloft.net \
--cc=gerald.schaefer@de.ibm.com \
--cc=gregkh@linuxfoundation.org \
--cc=heiko.carstens@de.ibm.com \
--cc=jgg@ziepe.ca \
--cc=jhogan@kernel.org \
--cc=keescook@chromium.org \
--cc=kirill@shutemov.name \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux-sh@vger.kernel.org \
--cc=linux-snps-arc@lists.infradead.org \
--cc=linux@armlinux.org.uk \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mhocko@kernel.org \
--cc=mingo@kernel.org \
--cc=mpe@ellerman.id.au \
--cc=paul.burton@mips.com \
--cc=paulus@samba.org \
--cc=penguin-kernel@i-love.sakura.ne.jp \
--cc=peterz@infradead.org \
--cc=ralf@linux-mips.org \
--cc=rppt@linux.vnet.ibm.com \
--cc=schowdary@nvidia.com \
--cc=schwidefsky@de.ibm.com \
--cc=sparclinux@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=vbabka@suse.cz \
--cc=vgupta@synopsys.com \
--cc=willy@infradead.org \
--cc=x86@kernel.org \
--cc=yamada.masahiro@socionext.com \
/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).