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Code Issues Releases Activity

Really initialize `write_region_inhibit_fsync' when interactive.

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* fileio.c (init_fileio): Move `write_region_inhibit_fsync'
initialization here ...
(syms_of_fileio): ... from here.
This commit is contained in:
Romain Francoise 2013-11-23 12:32:05 +01:00
parent 40dd812fa3
commit 1db72ad330
2 changed files with 25 additions and 17 deletions
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6
src/ChangeLog
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@ -1,3 +1,9 @@
2013-11-23 Romain Francoise <romain@orebokech.com>
* fileio.c (init_fileio): Move `write_region_inhibit_fsync'
initialization here ...
(syms_of_fileio): ... from here.
2013-11-23 Stefan Monnier <monnier@iro.umontreal.ca>
* lread.c (init_lread): Fix int/Lisp_Object mixup.

36
src/fileio.c
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@ -5773,6 +5773,24 @@ void
init_fileio (void)
{
valid_timestamp_file_system = 0;
/* fsync can be a significant performance hit. Often it doesn't
suffice to make the file-save operation survive a crash. For
batch scripts, which are typically part of larger shell commands
that don't fsync other files, its effect on performance can be
significant so its utility is particularly questionable.
Hence, for now by default fsync is used only when interactive.
For more on why fsync often fails to work on today's hardware, see:
Zheng M et al. Understanding the robustness of SSDs under power fault.
11th USENIX Conf. on File and Storage Technologies, 2013 (FAST '13), 271-84
http://www.usenix.org/system/files/conference/fast13/fast13-final80.pdf
For more on why fsync does not suffice even if it works properly, see:
Roche X. Necessary step(s) to synchronize filename operations on disk.
Austin Group Defect 672, 2013-03-19
http://austingroupbugs.net/view.php?id=672 */
write_region_inhibit_fsync = noninteractive;
}
void
@ -5985,28 +6003,12 @@ in the buffer; this is the default behavior, because the auto-save
file is usually more useful if it contains the deleted text. */);
Vauto_save_include_big_deletions = Qnil;
/* fsync can be a significant performance hit. Often it doesn't
suffice to make the file-save operation survive a crash. For
batch scripts, which are typically part of larger shell commands
that don't fsync other files, its effect on performance can be
significant so its utility is particularly questionable.
Hence, for now by default fsync is used only when interactive.
For more on why fsync often fails to work on today's hardware, see:
Zheng M et al. Understanding the robustness of SSDs under power fault.
11th USENIX Conf. on File and Storage Technologies, 2013 (FAST '13), 271-84
http://www.usenix.org/system/files/conference/fast13/fast13-final80.pdf
For more on why fsync does not suffice even if it works properly, see:
Roche X. Necessary step(s) to synchronize filename operations on disk.
Austin Group Defect 672, 2013-03-19
http://austingroupbugs.net/view.php?id=672 */
DEFVAR_BOOL ("write-region-inhibit-fsync", write_region_inhibit_fsync,
doc: /* Non-nil means don't call fsync in `write-region'.
This variable affects calls to `write-region' as well as save commands.
Setting this to nil may avoid data loss if the system loses power or
the operating system crashes. */);
write_region_inhibit_fsync = noninteractive;
write_region_inhibit_fsync = 0; /* See also `init_fileio' above. */
DEFVAR_BOOL ("delete-by-moving-to-trash", delete_by_moving_to_trash,
doc: /* Specifies whether to use the system's trash can.