git/list[1] front-page[2] threads[3] people[4] search[5] about
 

Re: [PATCH 0/17] Sliding window mmap for packfiles.

From
FMFrancis Moreau <francis.moro@gmail.com>
Date
Dec 24, 2006, 09:36 UTC
Message-ID
<38b2ab8a0612240136r559376d4s14af3123f762a45d@mail.gmail.com>
In-Reply-To
<20061224090508.GF7443@spearce.org>
On 12/24/06, Shawn Pearce <spearce@spearce.org> wrote:
Show 20 quoted lines
> Francis Moreau <francis.moro@gmail.com> wrote:
> > On 12/23/06, Shawn O. Pearce <spearce@spearce.org> wrote:
> > >This 17 patch series implements my much discussed, but never produced
> > [snip]
> > >
> > >This series also permits accessing packfiles up to 4 GiB in size,
> > >even on systems which permit only 2 GiB of virtual memory within
> > >a single process (e.g. Windows and some older UNIXes).  Of course
> >
> > Just out of curiosity, do you mean that there are some OS running on
> > 32 bits machines which allow 4GiB size of virtual memory within a
> > single process ? If so, could you give an example of such OS ?
>
> No.  What I meant was the Git packfile/index format currently
> supports up to 4 GiB of data in a single packfile.  But *no*
> OS using 32 bit virtual address space would permit us to access
> that packfile prior to this series as we would have *no* memory
> left for a stack, let alone for parsing commits, etc., as *all*
> of the address space would have been dedicated to the packfile.
>
ok.
Show 7 quoted lines
> However with this series even a 32 bit OS which only permits
> processes to have at most 2 GiB of address space (2 GiB split
> between kernel space and userspace) can access packfiles up
> to 4 GiB in size.  That seems to be the split most OSes wind
> up using, if they didn't push it out to 3.2 GiB like Linux
> and Solaris have done.
>
Does it still needed for 64 bit OS ?

if not, can the overhead (if there is a significant one) implied by your rework be avoid for such cases ?

> This series is a good change because Git can now really make
> full use of the space allowed by a single packfile.  :-)
>
Yes I agree with you.
-- 
Francis
Previous: Shawn PearceNext: Shawn Pearce
Message 6 of 9 in “Sliding window mmap for packfiles.”
  1. 0/17 Sliding window mmap for packfiles.Shawn O. Pearce, Dec 23, 2006
  2. Junio C HamanoDec 23, 2006
  3. Shawn PearceDec 23, 2006
  4. Francis MoreauDec 24, 2006
  5. Shawn PearceDec 24, 2006
  6. Francis MoreauDec 24, 2006
  7. Shawn PearceDec 24, 2006
  8. Andy WhitcroftJan 2, 2007
  9. Linus TorvaldsDec 24, 2006

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.