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do_fork: Increase tid table size when allowing oversubscription

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The size of tid table needs to be more than #CPUs when CPU oversubscription
is needed.

Note that the max number of simultaneous threads are the min of the
following two:
(1) Number of mcexec worker threads
(2) NR_TID defined in kernel/syscall.c

Change-Id: I425189da415e1d3a763ad62567950d001850cf0d
This commit is contained in:
Masamichi Takagi
2018-08-20 10:02:07 +09:00
committed by Dominique Martinet
parent 0b2169964a
commit affe3e9010
1 changed files with 20 additions and 6 deletions
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26
kernel/syscall.c
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@@ -132,6 +132,13 @@ int prepare_process_ranges_args_envs(struct thread *thread,
static void do_mod_exit(int status); static void do_mod_exit(int status);
#endif #endif
/* Size of tid table. It needs to be more than #CPUs when CPU
* oversubscription is needed. The examples of CPU oversubscription are:
* (1) pmi_proxy + gdb + #CPU OMP threads
* (2) pmi_proxy + #CPU OMP threads + POSIX AIO IO + POSIX AIO notification
*/
#define NR_TIDS (allow_oversubscribe ? (num_processors * 2) : num_processors)
static void send_syscall(struct syscall_request *req, int cpu, int pid, struct syscall_response *res) static void send_syscall(struct syscall_request *req, int cpu, int pid, struct syscall_response *res)
{ {
struct ikc_scd_packet packet IHK_DMA_ALIGN; struct ikc_scd_packet packet IHK_DMA_ALIGN;
@@ -2430,14 +2437,15 @@ unsigned long do_fork(int clone_flags, unsigned long newsp,
mcs_rwlock_writer_lock(&newproc->threads_lock, &lock); mcs_rwlock_writer_lock(&newproc->threads_lock, &lock);
/* Obtain mcexec TIDs if not known yet */ /* Obtain mcexec TIDs if not known yet */
if (!newproc->nr_tids) { if (!newproc->nr_tids) {
tids = kmalloc(sizeof(int) * num_processors, IHK_MC_AP_NOWAIT); tids = kmalloc(sizeof(int) * NR_TIDS, IHK_MC_AP_NOWAIT);
if (!tids) { if (!tids) {
mcs_rwlock_writer_unlock(&newproc->threads_lock, &lock); mcs_rwlock_writer_unlock(&newproc->threads_lock, &lock);
release_cpuid(cpuid); release_cpuid(cpuid);
return -ENOMEM; return -ENOMEM;
} }
newproc->tids = kmalloc(sizeof(struct mcexec_tid) * num_processors, IHK_MC_AP_NOWAIT); newproc->tids = kmalloc(sizeof(struct mcexec_tid) *
NR_TIDS, IHK_MC_AP_NOWAIT);
if (!newproc->tids) { if (!newproc->tids) {
mcs_rwlock_writer_unlock(&newproc->threads_lock, &lock); mcs_rwlock_writer_unlock(&newproc->threads_lock, &lock);
kfree(tids); kfree(tids);
@@ -2445,10 +2453,11 @@ unsigned long do_fork(int clone_flags, unsigned long newsp,
return -ENOMEM; return -ENOMEM;
} }
settid(new, num_processors, tids); settid(new, NR_TIDS, tids);
for (i = 0; (i < num_processors) && tids[i]; ++i) { for (i = 0; (i < NR_TIDS) && tids[i]; ++i) {
dkprintf("%s: tid[%d]: %d\n", __FUNCTION__, i, tids[i]); dkprintf("%s: tids[%d]: %d\n",
__func__, i, tids[i]);
newproc->tids[i].tid = tids[i]; newproc->tids[i].tid = tids[i];
newproc->tids[i].thread = NULL; newproc->tids[i].thread = NULL;
++newproc->nr_tids; ++newproc->nr_tids;
@@ -2477,7 +2486,12 @@ retry_tid:
/* TODO: spawn more mcexec threads */ /* TODO: spawn more mcexec threads */
if (!new->tid) { if (!new->tid) {
release_cpuid(cpuid); release_cpuid(cpuid);
kprintf("%s: no more TIDs available\n"); kprintf("%s: no more TIDs available\n", __func__);
for (i = 0; i < newproc->nr_tids; ++i) {
kprintf("%s: i=%d,tid=%d,thread=%p\n",
__func__, i, newproc->tids[i].tid,
newproc->tids[i].thread);
}
return -ENOMEM; return -ENOMEM;
} }
} }