From: Michal Hocko <mhocko@suse.com>
To: Ryan Roberts <ryan.roberts@arm.com>
Cc: David Hildenbrand <david@redhat.com>,
Yin Fengwei <fengwei.yin@intel.com>,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Nick Piggin <npiggin@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, "Huang, Ying" <ying.huang@intel.com>
Subject: Re: [PATCH v1 0/9] mm/memory: optimize unmap/zap with PTE-mapped THP
Date: Wed, 31 Jan 2024 15:08:21 +0100 [thread overview]
Message-ID: <ZbpUVXa-Aujp6gWO@tiehlicka> (raw)
In-Reply-To: <1fd26a83-8e6f-4b96-9d27-dd46de9488cc@arm.com>
On Wed 31-01-24 10:26:13, Ryan Roberts wrote:
> IIRC there is an option to zero memory when it is freed back to the buddy? So
> that could be a place where time is proportional to size rather than
> proportional to folio count? But I think that option is intended for debug only?
> So perhaps not a problem in practice?
init_on_free is considered a security/hardening feature more than a
debugging one. It will surely add an overhead and I guess this is
something people who use it know about. The batch size limit is a latency
reduction feature for !PREEMPT kernels but by no means it should be
considered low latency guarantee feature. A lot of has changed since
the limit was introduced and the current latency numbers will surely be
different than back then. As long as soft lockups do not trigger again
this should be acceptable IMHO.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2024-01-31 14:08 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-29 14:32 David Hildenbrand
2024-01-29 14:32 ` [PATCH v1 1/9] mm/memory: factor out zapping of present pte into zap_present_pte() David Hildenbrand
2024-01-30 8:13 ` Ryan Roberts
2024-01-30 8:41 ` David Hildenbrand
2024-01-30 8:46 ` Ryan Roberts
2024-01-30 8:49 ` David Hildenbrand
2024-01-29 14:32 ` [PATCH v1 2/9] mm/memory: handle !page case in zap_present_pte() separately David Hildenbrand
2024-01-30 8:20 ` Ryan Roberts
2024-01-29 14:32 ` [PATCH v1 3/9] mm/memory: further separate anon and pagecache folio handling in zap_present_pte() David Hildenbrand
2024-01-30 8:31 ` Ryan Roberts
2024-01-30 8:37 ` David Hildenbrand
2024-01-30 8:45 ` Ryan Roberts
2024-01-30 8:47 ` David Hildenbrand
2024-01-29 14:32 ` [PATCH v1 4/9] mm/memory: factor out zapping folio pte into zap_present_folio_pte() David Hildenbrand
2024-01-30 8:47 ` Ryan Roberts
2024-01-29 14:32 ` [PATCH v1 5/9] mm/mmu_gather: pass "delay_rmap" instead of encoded page to __tlb_remove_page_size() David Hildenbrand
2024-01-30 8:41 ` Ryan Roberts
2024-01-29 14:32 ` [PATCH v1 6/9] mm/mmu_gather: define ENCODED_PAGE_FLAG_DELAY_RMAP David Hildenbrand
2024-01-30 9:03 ` Ryan Roberts
2024-01-29 14:32 ` [PATCH v1 7/9] mm/mmu_gather: add __tlb_remove_folio_pages() David Hildenbrand
2024-01-30 9:21 ` Ryan Roberts
2024-01-30 9:33 ` David Hildenbrand
2024-01-29 14:32 ` [PATCH v1 8/9] mm/mmu_gather: add tlb_remove_tlb_entries() David Hildenbrand
2024-01-30 9:33 ` Ryan Roberts
2024-01-29 14:32 ` [PATCH v1 9/9] mm/memory: optimize unmap/zap with PTE-mapped THP David Hildenbrand
2024-01-30 9:08 ` David Hildenbrand
2024-01-30 9:48 ` Ryan Roberts
2024-01-31 10:21 ` David Hildenbrand
2024-01-31 10:31 ` Ryan Roberts
2024-01-31 11:13 ` David Hildenbrand
2024-01-31 2:30 ` Yin Fengwei
2024-01-31 10:30 ` David Hildenbrand
2024-01-31 10:43 ` Yin, Fengwei
2024-01-31 2:20 ` [PATCH v1 0/9] " Yin Fengwei
2024-01-31 10:16 ` David Hildenbrand
2024-01-31 10:26 ` Ryan Roberts
2024-01-31 14:08 ` Michal Hocko [this message]
2024-01-31 14:20 ` David Hildenbrand
2024-01-31 14:03 ` Michal Hocko
2024-01-31 10:43 ` David Hildenbrand
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