Daniel Jordan <[email protected]> writes: > On Fri, Jun 22, 2018 at 11:51:35AM +0800, Huang, Ying wrote: >> +static unsigned char swap_free_cluster(struct swap_info_struct *si, >> + swp_entry_t entry) > ... >> + /* Cluster has been split, free each swap entries in cluster */ >> + if (!cluster_is_huge(ci)) { >> + unlock_cluster(ci); >> + for (i = 0; i < SWAPFILE_CLUSTER; i++, entry.val++) { >> + if (!__swap_entry_free(si, entry, 1)) { >> + free_entries++; >> + free_swap_slot(entry); >> + } >> + } > > Is is better on average to use __swap_entry_free_locked instead of > __swap_entry_free here? I'm not sure myself, just asking. > > As it's written, if the cluster's been split, we always take and drop the > cluster lock 512 times, but if we don't expect to call free_swap_slot that > often, then we could just drop and retake the cluster lock inside the > innermost > 'if' against the possibility that free_swap_slot eventually makes us take the > cluster lock again.
Yes. This is a good idea. Thanks for your suggestion! I will change this in the next version. Best Regards, Huang, Ying > ... >> + return !(free_entries == SWAPFILE_CLUSTER); > > return free_entries != SWAPFILE_CLUSTER;
