From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Date: Tue, 15 Oct 2019 11:46:11 +0000 Subject: Re: [PATCH V6 2/2] mm/debug: Add tests validating architecture page table helpers Message-Id: <20191015114611.GC317@dhcp22.suse.cz> List-Id: References: <1571131302-32290-1-git-send-email-anshuman.khandual@arm.com> <1571131302-32290-3-git-send-email-anshuman.khandual@arm.com> In-Reply-To: <1571131302-32290-3-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Anshuman Khandual Cc: Mark Rutland , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , James Hogan , Tetsuo Handa , Heiko Carstens , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Hansen , Paul Mackerras , sparclinux@vger.kernel.org, Thomas Gleixner , linux-s390@vger.kernel.org, Michael Ellerman , x86@kernel.org, Russell King - ARM Linux , Matthew Wilcox , Steven Price , Jason Gunthorpe , Gerald Schaefer , linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Kees Cook , Masahiro Yamada , Mark Brown , "Kirill A . Shutemov" , Dan Williams , Vlastimil Babka , Christophe Leroy , Sri Krishna chowdary , Ard Biesheuvel , Greg Kroah-Hartman , linux-mips@vger.kernel.org, Ralf Baechle , Paul Burton , Mike Rapoport , Vineet Gupta , Martin Schwidefsky , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" On Tue 15-10-19 14:51:42, Anshuman Khandual 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. > > Test page table and memory pages creating it's entries at various level are > all allocated from system memory with required size and alignments. But if > memory pages with required size and alignment could not be allocated, then > all depending individual tests are just skipped afterwards. This test gets > called right after init_mm_internals() required for alloc_contig_range() to > work correctly. > > 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. A highlevel description of tests and what they are testing for would be really appreciated. Who wants to run these tests and why/when? What kind of bugs would get detected? In short why do we really need/want this code in the tree? -- Michal Hocko SUSE Labs