From: Matthew Wilcox <willy@infradead.org>
To: James Houghton <jthoughton@google.com>
Cc: Michal Hocko <mhocko@suse.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
David Rientjes <rientjes@google.com>,
linux-mm@kvack.org, David Hildenbrand <david@redhat.com>,
John Hubbard <jhubbard@nvidia.com>, Peter Xu <peterx@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>, Zi Yan <ziy@nvidia.com>
Subject: Re: [Invitation] Linux MM Alignment Session on HugeTLB Core MM Convergence on Wednesday
Date: Thu, 15 Jun 2023 18:18:33 +0100 [thread overview]
Message-ID: <ZItH6VWksesISUUJ@casper.infradead.org> (raw)
In-Reply-To: <CADrL8HU7nvcsfPzEQZOXBAr=M+jDymm1btkNb_zjUfCUNXxZ3A@mail.gmail.com>
On Thu, Jun 15, 2023 at 10:00:41AM -0700, James Houghton wrote:
> I can't speak in detail about how databases recover from memory
> poison. Mike, maybe you can share more details?
Speaking generally (this would describe MySQL as well as any number of
proprietary databases), hugetlbfs is used by databases as a supplier
of memory to their userspace buffer cache. As database blocks are
needed, they're read from storage using O_DIRECT. Depending on the
database, they may or may not be updated in place.
Just as in our page cache, if the hwpoison hits in a clean block, it
can discard the block and re-read it. If it hits in a dirty block, it's
Game Over. Most blocks are clean. A 1GB page contains so many blocks
that taking out the entire 1GB is guaranteed to take out a dirty block.
Taking out a single 4kB page is likely to take out only clean blocks.
next prev parent reply other threads:[~2023-06-15 17:18 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <c5afdf35-a5fa-03e2-348d-cf1d990fc389@google.com>
[not found] ` <20230614230458.GB3559@monkey>
2023-06-15 1:12 ` David Rientjes
2023-06-15 8:04 ` Michal Hocko
2023-06-15 8:29 ` David Hildenbrand
2023-06-15 17:24 ` James Houghton
2023-06-15 18:58 ` Peter Xu
2023-06-15 18:31 ` Mike Kravetz
2023-06-15 17:00 ` James Houghton
2023-06-15 17:18 ` Matthew Wilcox [this message]
2023-06-15 17:59 ` Mike Kravetz
2023-06-13 2:01 David Rientjes
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