diff options
author | Jeff King <peff@peff.net> | 2012-02-02 12:18:29 +0400 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2012-02-02 22:36:07 +0400 |
commit | 78db6ea9dc1a872f9d07a36fe7aec700a5c963b9 (patch) | |
tree | 9dd1308cd344c12239a17a698355c836e49c7200 /builtin/grep.c | |
parent | 828ea97de486c1693d6e4f2c7347acb50235a85d (diff) |
grep: make locking flag global
The low-level grep code traditionally didn't care about
threading, as it doesn't do any threading itself and didn't
call out to other non-thread-safe code. That changed with
0579f91 (grep: enable threading with -p and -W using lazy
attribute lookup, 2011-12-12), which pushed the lookup of
funcname attributes (which is not thread-safe) into the
low-level grep code.
As a result, the low-level code learned about a new global
"grep_attr_mutex" to serialize access to the attribute code.
A multi-threaded caller (e.g., builtin/grep.c) is expected
to initialize the mutex and set "use_threads" in the
grep_opt structure. The low-level code only uses the lock if
use_threads is set.
However, putting the use_threads flag into the grep_opt
struct is not the most logical place. Whether threading is
in use is not something that matters for each call to
grep_buffer, but is instead global to the whole program
(i.e., if any thread is doing multi-threaded grep, every
other thread, even if it thinks it is doing its own
single-threaded grep, would need to use the locking). In
practice, this distinction isn't a problem for us, because
the only user of multi-threaded grep is "git-grep", which
does nothing except call grep.
This patch turns the opt->use_threads flag into a global
flag. More important than the nit-picking semantic argument
above is that this means that the locking functions don't
need to actually have access to a grep_opt to know whether
to lock. Which in turn can make adding new locks simpler, as
we don't need to pass around a grep_opt.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'builtin/grep.c')
-rw-r--r-- | builtin/grep.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/builtin/grep.c b/builtin/grep.c index 9ce064ac11..5b881870f6 100644 --- a/builtin/grep.c +++ b/builtin/grep.c @@ -259,6 +259,7 @@ static void start_threads(struct grep_opt *opt) pthread_cond_init(&cond_add, NULL); pthread_cond_init(&cond_write, NULL); pthread_cond_init(&cond_result, NULL); + grep_use_locks = 1; for (i = 0; i < ARRAY_SIZE(todo); i++) { strbuf_init(&todo[i].out, 0); @@ -307,6 +308,7 @@ static int wait_all(void) pthread_cond_destroy(&cond_add); pthread_cond_destroy(&cond_write); pthread_cond_destroy(&cond_result); + grep_use_locks = 0; return hit; } @@ -1030,8 +1032,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix) use_threads = 0; #endif - opt.use_threads = use_threads; - #ifndef NO_PTHREADS if (use_threads) { if (opt.pre_context || opt.post_context || opt.file_break || |