gc --auto: exclude base pack if not enough mem to "repack -ad"

pack-objects could be a big memory hog especially on large repos,
everybody knows that. The suggestion to stick a .keep file on the
giant base pack to avoid this problem is also known for a long time.

Recent patches add an option to do just this, but it has to be either
configured or activated manually. This patch lets `git gc --auto`
activate this mode automatically when it thinks `repack -ad` will use
a lot of memory and start affecting the system due to swapping or
flushing OS cache.

gc --auto decides to do this based on an estimation of pack-objects
memory usage, which is quite accurate at least for the heap part, and
whether that fits in half of system memory (the assumption here is for
desktop environment where there are many other applications running).

This mechanism only kicks in if gc.bigBasePackThreshold is not configured.
If it is, it is assumed that the user already knows what they want.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Nguyễn Thái Ngọc Duy
2018-04-15 17:36:17 +02:00
committed by Junio C Hamano
parent 8fc6776247
commit 9806f5a7bf
7 changed files with 119 additions and 4 deletions

View File

@ -284,6 +284,10 @@ extern char *gitdirname(char *);
#include <openssl/err.h>
#endif
#ifdef HAVE_SYSINFO
# include <sys/sysinfo.h>
#endif
/* On most systems <netdb.h> would have given us this, but
* not on some systems (e.g. z/OS).
*/