> Date: Tue, 24 Mar 2020 15:18:13 +0100
> From: Martin Pieuchot <[email protected]>
>
> As soon as an entry is found on `pmr_control.allocs' the boolean
> `work_done' will be set to true. So it is impossible to reach the
> case below that sets UVM_PMA_FAIL.
>
> CID 1453061 Logically dead code
>
> Ok?
Almost certainly not.
> Index: uvm/uvm_pdaemon.c
> ===================================================================
> RCS file: /cvs/src/sys/uvm/uvm_pdaemon.c,v
> retrieving revision 1.85
> diff -u -p -u -4 -r1.85 uvm_pdaemon.c
> --- uvm/uvm_pdaemon.c 30 Dec 2019 23:58:38 -0000 1.85
> +++ uvm/uvm_pdaemon.c 24 Mar 2020 14:12:22 -0000
> @@ -209,9 +209,8 @@ void
> uvm_pageout(void *arg)
> {
> struct uvm_constraint_range constraint;
> struct uvm_pmalloc *pma;
> - int work_done;
> int npages = 0;
>
> /* ensure correct priority and set paging parameters... */
> uvm.pagedaemon_proc = curproc;
> @@ -222,9 +221,8 @@ uvm_pageout(void *arg)
> uvm_unlock_pageq();
>
> for (;;) {
> long size;
> - work_done = 0; /* No work done this iteration. */
>
> uvm_lock_fpageq();
> if (!uvm_nowait_failed && TAILQ_EMPTY(&uvm.pmr_control.allocs))
> {
> msleep_nsec(&uvm.pagedaemon, &uvm.fpageqlock, PVM,
> @@ -281,9 +279,8 @@ uvm_pageout(void *arg)
> if (pma != NULL ||
> ((uvmexp.free - BUFPAGES_DEFICIT) < uvmexp.freetarg) ||
> ((uvmexp.inactive + BUFPAGES_INACT) < uvmexp.inactarg)) {
> uvmpd_scan();
> - work_done = 1; /* XXX we hope... */
> }
>
> /*
> * if there's any free memory to be had,
> @@ -296,10 +293,8 @@ uvm_pageout(void *arg)
> }
>
> if (pma != NULL) {
> pma->pm_flags &= ~UVM_PMA_BUSY;
> - if (!work_done)
> - pma->pm_flags |= UVM_PMA_FAIL;
> if (pma->pm_flags & (UVM_PMA_FAIL | UVM_PMA_FREED)) {
> pma->pm_flags &= ~UVM_PMA_LINKED;
> TAILQ_REMOVE(&uvm.pmr_control.allocs, pma,
> pmq);
>
>
