From: Dave Hansen <dave.hansen@intel.com>
To: Byungchul Park <byungchul@sk.com>, "Huang, Ying" <ying.huang@intel.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kernel_team@skhynix.com, akpm@linux-foundation.org,
vernhao@tencent.com, mgorman@techsingularity.net,
hughd@google.com, willy@infradead.org, david@redhat.com,
peterz@infradead.org, luto@kernel.org, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
rjgolo@gmail.com
Subject: Re: [PATCH v10 00/12] LUF(Lazy Unmap Flush) reducing tlb numbers over 90%
Date: Thu, 30 May 2024 06:50:48 -0700 [thread overview]
Message-ID: <2a0f8cc9-a061-45cd-81df-b65d4b454b77@intel.com> (raw)
In-Reply-To: <20240530084120.GA12940@system.software.com>
On 5/30/24 01:41, Byungchul Park wrote:
> LUF should not optimize tlb flushes for mappings that users explicitly
> change e.g. through mmap() and munmap().
We are thoroughly going around in circles at this point.
I'm not quite sure what to do. Ying and I see a problem that we've
tried to explain a couple of times. We've tried to show the connection
between a LUF-elided TLB flush and how that could affect a later
munmap() or mmap(MAP_FIXED).
But these responses seem to keep going back to the fact that LUF doesn't
directly affect munmap(), which is true, but quite irrelevant to the
problem being described.
So we're at an impasse.
Byungchul, perhaps you should spin another series and maybe Ying and I
have to write up a test case to show the bug that we see. Or perhaps
someone else can jump into the thread and bridge the communication gap.
next prev parent reply other threads:[~2024-05-30 13:50 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-10 6:51 [PATCH v10 00/12] LUF(Lazy Unmap Flush) reducing tlb numbers over 90% Byungchul Park
2024-05-10 6:51 ` [PATCH v10 01/12] x86/tlb: add APIs manipulating tlb batch's arch data Byungchul Park
2024-05-10 6:51 ` [PATCH v10 02/12] arm64: tlbflush: " Byungchul Park
2024-05-10 6:51 ` [PATCH v10 03/12] riscv, tlb: " Byungchul Park
2024-05-10 6:51 ` [PATCH v10 04/12] x86/tlb, riscv/tlb, mm/rmap: separate arch_tlbbatch_clear() out of arch_tlbbatch_flush() Byungchul Park
2024-05-10 6:51 ` [PATCH v10 05/12] mm: buddy: make room for a new variable, ugen, in struct page Byungchul Park
2024-05-10 6:52 ` [PATCH v10 06/12] mm: add folio_put_ugen() to deliver unmap generation number to pcp or buddy Byungchul Park
2024-05-10 6:52 ` [PATCH v10 07/12] mm: add a parameter, unmap generation number, to free_unref_folios() Byungchul Park
2024-05-10 6:52 ` [PATCH v10 08/12] mm/rmap: recognize read-only tlb entries during batched tlb flush Byungchul Park
2024-05-10 6:52 ` [PATCH v10 09/12] mm: implement LUF(Lazy Unmap Flush) defering tlb flush when folios get unmapped Byungchul Park
2024-05-10 6:52 ` [PATCH v10 10/12] mm: separate move/undo parts from migrate_pages_batch() Byungchul Park
2024-05-10 6:52 ` [PATCH v10 11/12] mm, migrate: apply luf mechanism to unmapping during migration Byungchul Park
2024-05-10 6:52 ` [PATCH v10 12/12] mm, vmscan: apply luf mechanism to unmapping during folio reclaim Byungchul Park
2024-05-11 6:54 ` [PATCH v10 00/12] LUF(Lazy Unmap Flush) reducing tlb numbers over 90% Huang, Ying
2024-05-13 1:41 ` Byungchul Park
2024-05-11 7:15 ` Huang, Ying
2024-05-13 1:44 ` Byungchul Park
2024-05-22 2:16 ` Byungchul Park
2024-05-22 7:38 ` Huang, Ying
2024-05-22 10:27 ` Byungchul Park
2024-05-22 14:15 ` Byungchul Park
2024-05-24 17:16 ` Dave Hansen
2024-05-27 1:57 ` Byungchul Park
2024-05-27 2:43 ` Dave Hansen
2024-05-27 3:46 ` Byungchul Park
2024-05-27 4:19 ` Byungchul Park
2024-05-27 4:25 ` Byungchul Park
2024-05-27 22:58 ` Byungchul Park
2024-05-29 2:16 ` Huang, Ying
2024-05-30 1:02 ` Byungchul Park
2024-05-27 3:10 ` Huang, Ying
2024-05-27 3:56 ` Byungchul Park
2024-05-28 15:14 ` Dave Hansen
2024-05-29 5:00 ` Byungchul Park
2024-05-29 16:41 ` Dave Hansen
2024-05-30 0:50 ` Byungchul Park
2024-05-30 0:59 ` Byungchul Park
2024-05-30 1:11 ` Huang, Ying
2024-05-30 1:33 ` Byungchul Park
2024-05-30 7:18 ` Byungchul Park
2024-05-30 8:24 ` Huang, Ying
2024-05-30 8:41 ` Byungchul Park
2024-05-30 13:50 ` Dave Hansen [this message]
2024-05-31 2:06 ` Byungchul Park
2024-05-30 9:33 ` Byungchul Park
2024-05-31 1:45 ` Huang, Ying
2024-05-31 2:20 ` Byungchul Park
2024-05-28 8:41 ` David Hildenbrand
2024-05-29 4:39 ` Byungchul Park
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