On Mon, Mar 22, 2021 at 01:11:49PM +0100, Ævar Arnfjörð Bjarmason wrote:
Extend the SPATCH_BATCH_SIZE facility added in
960154b9c17 (coccicheck: optionally batch spatch invocations,
2019-05-06) and bcb4edf7af7 (coccicheck: make batch size of 0 mean
"unlimited", 2019-05-08) to allow for both setting
SPATCH_BATCH_SIZE=N, and also to have a more advanced SPATCH_XARGS
argument.
The reason to replace the "$$limit" is that now you actually see under
V=1 what argument your program will get invoked with.
The reason for the "9999" limit is that if you e.g. try to define an
"$(XARGS)" which is conditionally an empty string or not depending on
this setting then e.g.:
echo $(FILES) | $(XARGS) $(XARGS_FLAGS) $(SPATCH)
Over multiple lines with "\" will error out. I think just setting it
to "xargs -n 9999" as a trivial workaround is the best solution here.
I don't understand this 9999 comment. The original was sometimes setting
$limit to the empty string, and then doing:
xargs $limit
How is that any different than setting SPATCH_XARGS to just "xargs" for
the unlimited case?
quoted hunk ↗ jump to hunk
+# For the 'coccicheck' target; SPATCH_XARGS can be used to manually
+# tweak the xargs invocation. By default we invoke "xargs -n 1", and
+# "xargs -n 9999" under SPATCH_BATCH_SIZE=0.
+#
+# Setting SPATCH_XARGS overrides SPATCH_BATCH_SIZE. To get concurrency
+# when targeting a single contrib/coccinelle/%.patch use e.g. "-P" if
+# your xargs(1) supports it:
+#
+# make contrib/coccinelle/strbuf.cocci.patch SPATCH_XARGS="xargs -P 8 -n 8"
+#
+# Or a combination -jN and "xargs -P":
+#
+# make -j4 coccicheck SPATCH_XARGS="xargs -P 2 -n 8"
As I mentioned in the last round, using "-P" is racy. I'm not sure if
it's something we should be recommending to people.
-Peff