On 11/24/18 2:29 AM, Dr. David Alan Gilbert wrote:
static void
-update_compress_thread_counts(const CompressParam *param, int bytes_xmit)
+update_compress_thread_counts(CompressData *cd, int bytes_xmit)
Keep the const?
Yes, indeed. Will correct it in the next version.
+ if (deflateInit(&cd->stream, migrate_compress_level()) != Z_OK) {
+ g_free(cd->originbuf);
+ return -1;
+ }
Please print errors if you fail in any case so we can easily tell what
happened.
Sure, will do.
+ if (wait) {
+ cpu_relax();
+ goto retry;
Is there nothing better we can use to wait without eating CPU time?
There is a mechanism to wait without eating CPU time in the data
structure, but it makes sense to busy wait. There are 4 threads in the
workqueue, so you have to compare 1/4th of the time spent compressing a
page, with the trip into the kernel to wake you up. You're adding 20%
CPU usage, but I'm not surprised it's worthwhile.
Hmm OK; in that case it does at least need a comment because it's a bit
odd, and we should watch out how that scales - I guess it's less of
an overhead the more threads you use.
Sure, will add some comments to explain the purpose.
