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thread: rework tid batch to use helpers

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This commit is contained in:
Mateusz Guzik 2020-11-14 19:20:58 +00:00
parent 25600ad516
commit 5ef7b7a0f3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=367693
1 changed files with 66 additions and 13 deletions
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79
sys/kern/kern_thread.c
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@ -258,6 +258,54 @@ tid_free_batch(lwpid_t *batch, int n)
mtx_unlock(&tid_lock);
}
/*
* Batching for thread reapping.
*/
struct tidbatch {
lwpid_t tab[16];
int n;
};
static void
tidbatch_prep(struct tidbatch *tb)
{
tb->n = 0;
}
static void
tidbatch_add(struct tidbatch *tb, struct thread *td)
{
KASSERT(tb->n < nitems(tb->tab),
("%s: count too high %d", __func__, tb->n));
tb->tab[tb->n] = td->td_tid;
tb->n++;
}
static void
tidbatch_process(struct tidbatch *tb)
{
KASSERT(tb->n <= nitems(tb->tab),
("%s: count too high %d", __func__, tb->n));
if (tb->n == nitems(tb->tab)) {
tid_free_batch(tb->tab, tb->n);
tb->n = 0;
}
}
static void
tidbatch_final(struct tidbatch *tb)
{
KASSERT(tb->n <= nitems(tb->tab),
("%s: count too high %d", __func__, tb->n));
if (tb->n != 0) {
tid_free_batch(tb->tab, tb->n);
}
}
/*
* Prepare a thread for use.
*/
@ -487,8 +535,8 @@ void
thread_reap(void)
{
struct thread *itd, *ntd;
lwpid_t tidbatch[16];
int tidbatchn;
struct tidbatch tidbatch;
int tdcount;
/*
* Reading upfront is pessimal if followed by concurrent atomic_swap,
@ -499,24 +547,29 @@ thread_reap(void)
itd = (struct thread *)atomic_swap_ptr((uintptr_t *)&thread_zombies,
(uintptr_t)NULL);
tidbatchn = 0;
if (itd == NULL)
return;
tidbatch_prep(&tidbatch);
tdcount = 0;
while (itd != NULL) {
ntd = itd->td_zombie;
tidbatch[tidbatchn] = itd->td_tid;
tidbatchn++;
EVENTHANDLER_DIRECT_INVOKE(thread_dtor, itd);
tidbatch_add(&tidbatch, itd);
thread_cow_free(itd);
thread_free_batched(itd);
if (tidbatchn == nitems(tidbatch)) {
tid_free_batch(tidbatch, tidbatchn);
thread_count_sub(tidbatchn);
tidbatchn = 0;
tidbatch_process(&tidbatch);
tdcount++;
if (tdcount == 32) {
thread_count_sub(tdcount);
tdcount = 0;
}
itd = ntd;
}
if (tidbatchn != 0) {
tid_free_batch(tidbatch, tidbatchn);
thread_count_sub(tidbatchn);
tidbatch_final(&tidbatch);
if (tdcount != 0) {
thread_count_sub(tdcount);
}
}
@ -567,7 +620,6 @@ static void
thread_free_batched(struct thread *td)
{
EVENTHANDLER_DIRECT_INVOKE(thread_dtor, td);
lock_profile_thread_exit(td);
if (td->td_cpuset)
cpuset_rel(td->td_cpuset);
@ -588,6 +640,7 @@ thread_free(struct thread *td)
{
lwpid_t tid;
EVENTHANDLER_DIRECT_INVOKE(thread_dtor, td);
tid = td->td_tid;
thread_free_batched(td);
tid_free(tid);