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Re: [PATCH v3 03/16] index-helper: new daemon for caching index and related stuff

From
Duy Nguyen <pclouds@gmail.com>
Date
Apr 14, 2016, 10:43 UTC
Message-ID
<CACsJy8B6o-8YJYemcYX3NwyMaY9jV666ZwKJYwfbwMSmzM-YGw@mail.gmail.com>
In-Reply-To
<xmqqfuuqr9ca.fsf@gitster.mtv.corp.google.com>
On Wed, Apr 13, 2016 at 1:05 AM, Junio C Hamano <gitster@pobox.com> wrote:
Show 9 quoted lines
>>>  - access is slow (unless cached, but we can't be sure)
>>
>> We could solve this (and the other problem) with mlock.
>
> Probably you meant madvise(2)?
>
> For something of a size comparable to the index file held by
> index-helper-daemon in-core, I'd expect we wouldn't page too
> badly.

I had a look at linux implementation of madvise(MADV_WILLNEED). All it does is force populating the entire memory region, which is good. But I suspect when memory is under pressure, some pages may be reclaimed. index files in monster repo case can go up to a few hundred megabytes, chances of being reclaimed rise accordingly. But we can reconsider mlock() later when/if real problems happen.

-- 
Duy
Previous: David TurnerNext: Junio C Hamano
Message 16 of 37 in “index-helper, watchman”
  1. 00/16 index-helper, watchmanDavid Turner, Apr 6, 2016
  2. 01/16 read-cache.c: fix constness of verify_hdr()David Turner, Apr 6, 2016
  3. 02/16 read-cache: allow to keep mmap'd memory after readingDavid Turner, Apr 6, 2016
  4. 03/16 index-helper: new daemon for caching index and related stuffDavid Turner, Apr 6, 2016
  5. Johannes SixtApr 7, 2016
  6. Johannes SchindelinApr 7, 2016
  7. David TurnerApr 7, 2016
  8. Johannes SchindelinApr 8, 2016
  9. Duy NguyenApr 8, 2016
  10. David TurnerApr 8, 2016
  11. David TurnerApr 11, 2016
  12. Duy NguyenApr 12, 2016
  13. David TurnerApr 12, 2016
  14. Junio C HamanoApr 12, 2016
  15. David TurnerApr 13, 2016
  16. Duy NguyenApr 14, 2016
  17. Junio C HamanoApr 14, 2016
  18. David TurnerApr 14, 2016
  19. Duy NguyenApr 15, 2016
  20. Junio C HamanoApr 15, 2016
  21. 04/16 index-helper: add --strictDavid Turner, Apr 6, 2016
  22. 05/16 daemonize(): set a flag before exiting the main processDavid Turner, Apr 6, 2016
  23. 06/16 index-helper: add --detachDavid Turner, Apr 6, 2016
  24. 07/16 read-cache: add watchman 'WAMA' extensionDavid Turner, Apr 6, 2016
  25. 08/16 Add watchman support to reduce index refresh costDavid Turner, Apr 6, 2016
  26. 09/16 index-helper: use watchman to avoid refreshing index with lstat()David Turner, Apr 6, 2016
  27. Junio C HamanoApr 7, 2016
  28. Junio C HamanoApr 7, 2016
  29. David TurnerApr 8, 2016
  30. Junio C HamanoApr 8, 2016
  31. 10/16 update-index: enable/disable watchman supportDavid Turner, Apr 6, 2016
  32. 11/16 unpack-trees: preserve index extensionsDavid Turner, Apr 6, 2016
  33. 12/16 index-helper: kill modeDavid Turner, Apr 6, 2016
  34. 13/16 index-helper: don't run if already runningDavid Turner, Apr 6, 2016
  35. 14/16 index-helper: autorun modeDavid Turner, Apr 6, 2016
  36. 15/16 index-helper: optionally automatically runDavid Turner, Apr 6, 2016
  37. 16/16 read-cache: config for waiting for index-helperDavid Turner, Apr 6, 2016

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