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From: Bakul Shah <bakul@iitbombay.org>
To: Dan Cross <crossd@gmail.com>
Cc: TUHS main list <tuhs@minnie.tuhs.org>
Subject: Re: [TUHS] FreeBSD behind the times? (was: Favorite unix design principles?)
Date: Fri, 5 Feb 2021 19:01:48 -0800	[thread overview]
Message-ID: <0076DB2B-48BC-45D3-8278-3D8528431E87@iitbombay.org> (raw)
In-Reply-To: <CAEoi9W7ZYojXNJYcUo5pw2+v1kApAz1MA5qGW6+EQkK=8nDAxA@mail.gmail.com>

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> On Feb 5, 2021, at 6:06 PM, Dan Cross <crossd@gmail.com> wrote:
> 
> On Fri, Feb 5, 2021 at 7:04 PM Bakul Shah <bakul@iitbombay.org <mailto:bakul@iitbombay.org>> wrote:
> 
>     And you can keep track of mapped pages and read/write from them if
>     necessary even if you have a  separate cache for any compressed pages.
> 
> In essence you pass the ownership of a page's data from a compressed
> page cache to the mapped page. Just like in processor cache coherence
> algorithms there is one source of truth: the current owner of a cached
> unit (line or page or whatever). In other words, the you see via mmap(2)
> will be the exact same page you will see via read(2). Not having actually
> tried this I may have missed corner cases + any practical considerations
> complicating things but *conceptually* this doesn't seem hard.
> 
> In essence, that's what the merged page/buffer cache is all about: file IO (read/write) operations are satisfied from the same memory cache that backs up VM objects. I agree that conceptually it's not that complex; but that's not what ZFS does.

Good that we agree on that at least! This is why it would be good to hear from Bonwick/Moore.


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  reply	other threads:[~2021-02-06  3:02 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-25 11:10 [TUHS] Favorite unix design principles? Tyler Adams
2021-01-25 12:32 ` Steve Nickolas
2021-01-26  2:06   ` M Douglas McIlroy
2021-01-26  2:53     ` Steve Nickolas
2021-01-26 10:22     ` Tyler Adams
2021-01-26 12:26       ` John P. Linderman
2021-01-26 15:23       ` Clem Cole
2021-01-26 16:00         ` Niklas Karlsson
2021-01-26 16:13           ` Adam Thornton
     [not found]       ` <CAKH6PiXKjksEpQOMMMQTbcsMvX2thz3WzqjoRWJAsXnZ4Eq_iQ@mail.gmail.com>
2021-01-30 19:01         ` Tyler Adams
2021-01-30 19:50           ` Jon Steinhart
2021-01-30 20:06             ` Tyler Adams
2021-01-30 21:28               ` Clem Cole
2021-01-30 21:42                 ` Dave Horsfall
2021-01-30 21:45                 ` Tyler Adams
2021-01-30 22:31                   ` Larry McVoy
2021-01-30 22:28                 ` Larry McVoy
2021-01-30 23:11                   ` [TUHS] FreeBSD behind the times? (was: Favorite unix design principles?) Greg 'groggy' Lehey
2021-01-30 23:17                     ` Larry McVoy
2021-01-30 23:22                       ` Warner Losh
2021-01-30 23:31                         ` [TUHS] [SPAM] " Larry McVoy
2021-01-30 23:37                           ` Jon Steinhart
2021-01-30 23:54                             ` Larry McVoy
2021-01-31 12:23                               ` [TUHS] [SPAM] Re: FreeBSD behind the times? Dermot Tynan
2021-01-31  0:00                             ` [TUHS] [SPAM] Re: FreeBSD behind the times? (was: Favorite unix design principles?) Bakul Shah
2021-02-09  2:15                         ` [TUHS] " Will Senn
2021-02-09  2:16                           ` Will Senn
2021-02-09  2:30                             ` Greg 'groggy' Lehey
2021-01-31  0:39                     ` Steve Nickolas
2021-01-31  1:47                     ` Will Senn
2021-01-31  2:25                       ` Larry McVoy
2021-01-31  2:52                         ` Will Senn
2021-01-31  3:00                           ` Larry McVoy
2021-01-31  3:06                             ` Will Senn
2021-01-31  3:32                               ` John Cowan
2021-02-04  5:43                         ` Dave Horsfall
2021-02-04  6:10                           ` Angus Robinson
2021-02-04  7:46                             ` Andy Kosela
2021-02-04 22:25                             ` Dave Horsfall
2021-02-04 15:45                           ` Will Senn
2021-02-04 16:03                             ` Henry Bent
2021-02-04 16:32                             ` Dan Cross
2021-02-04 16:49                               ` Will Senn
2021-02-04 17:46                               ` Larry McVoy
2021-02-04 18:41                               ` Bakul Shah
2021-02-04 22:28                                 ` George Michaelson
2021-02-04 22:41                                   ` Bakul Shah
2021-02-05  0:33                                   ` Larry McVoy
2021-02-05  5:17                                     ` Bakul Shah
2021-02-05 14:18                                       ` Larry McVoy
2021-02-05 18:16                                         ` Warner Losh
2021-02-05 18:21                                         ` ron minnich
2021-02-06  0:03                                         ` Bakul Shah
2021-02-06  2:06                                           ` Dan Cross
2021-02-06  3:01                                             ` Bakul Shah [this message]
2021-02-06  1:18                                         ` John Gilmore
2021-02-06  1:43                                           ` joe mcguckin
2021-02-06  1:55                                           ` Bakul Shah
2021-02-05 20:50                             ` Dave Horsfall
2021-02-06  0:21                               ` Brad Spencer
2021-02-06  2:22                               ` Rico Pajarola
2021-02-06  2:55                                 ` Larry McVoy
2021-02-06  3:07                                   ` Will Senn
2021-02-27  8:54                                   ` Stuart Remphrey
2021-02-06  4:55                               ` John Cowan
2021-02-04  7:46                         ` Chris Torek
2021-02-04 15:47                           ` Will Senn
2021-02-11 21:01                         ` Angel M Alganza
2021-01-30 23:09                 ` [TUHS] Favorite unix design principles? John Cowan
2021-01-30 23:22                   ` Jon Steinhart

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