-int sgx_epc_cgroup_try_charge(struct sgx_epc_cgroup *epc_cg)
+int sgx_epc_cgroup_try_charge(struct sgx_epc_cgroup *epc_cg, bool reclaim)
{
- return misc_cg_try_charge(MISC_CG_RES_SGX_EPC, epc_cg->cg, PAGE_SIZE);
+ for (;;) {
+ if (!misc_cg_try_charge(MISC_CG_RES_SGX_EPC, epc_cg->cg,
+ PAGE_SIZE))
+ break;
+
+ if (sgx_epc_cgroup_lru_empty(epc_cg->cg))
+ return -ENOMEM;
+
+ if (signal_pending(current))
+ return -ERESTARTSYS;
+
+ if (!reclaim) {
+ queue_work(sgx_epc_cg_wq, &epc_cg->reclaim_work);
+ return -EBUSY;
+ }
+
+ if (!sgx_epc_cgroup_reclaim_pages(epc_cg->cg, false))
+ /* All pages were too young to reclaim, try again a little later */
+ schedule();
+ }
+
+ return 0;
}
Seems this code change is 90% similar to the existing code in the
sgx_alloc_epc_page():
...
for ( ; ; ) {
page = __sgx_alloc_epc_page();
if (!IS_ERR(page)) {
page->owner = owner;
break;
}
if (list_empty(&sgx_active_page_list))
return ERR_PTR(-ENOMEM);
if (!reclaim) {
page = ERR_PTR(-EBUSY);
break;
}
if (signal_pending(current)) {
page = ERR_PTR(-ERESTARTSYS);
break;
}
sgx_reclaim_pages();
cond_resched();
}
...
Is it better to move the logic/code change in try_charge() out to
sgx_alloc_epc_page() to unify them?
IIUC, the logic is quite similar: When you either failed to allocate one page,
or failed to charge one page, you try to reclaim EPC page(s) from the current
EPC cgroup, either directly or indirectly.
No?