Re: unconfiguring swap at shutdown

[Hubert Feyrer <hubert%feyrer.de@localhost>]

On Sat, 30 Aug 2008, Christos Zoulas wrote:
> The following patch removes swap devices at shutdown. This is useful for
> example when typing reboot and having a raidframe partition... Comments?

etc/rc.d/swap[12] run "swapctl -U -t {,no}blk" right now now shutdown.
Is that redundant / unneeded with your patch?


 - Hubert

> christos
>
> Index: kern/vfs_subr.c
> ===================================================================
> RCS file: /cvsroot/src/sys/kern/vfs_subr.c,v
> retrieving revision 1.355
> diff -u -u -r1.355 vfs_subr.c
> --- kern/vfs_subr.c     31 Jul 2008 05:38:05 -0000      1.355
> +++ kern/vfs_subr.c     28 Aug 2008 15:52:33 -0000
> @@ -114,6 +114,7 @@
> #include <uvm/uvm.h>
> #include <uvm/uvm_readahead.h>
> #include <uvm/uvm_ddb.h>
> +#include <uvm/uvm_swap.h>
>
> #include <sys/sysctl.h>
>
> @@ -2333,6 +2334,13 @@
>         if (panicstr != NULL)
>                 return;
>
> +#if defined(_KERNEL) && !defined(_RUMPKERNEL)
> +       /*
> +        * We need to turn off swap first before we unmount
> +        * /dev, because otherwise the spec_vnodes are bad.
> +        */
> +       uvm_swap_shutdown(l);
> +#endif
>         /* Release inodes held by texts before update. */
> #ifdef notdef
>         vnshutdown();
> Index: uvm/uvm_swap.c
> ===================================================================
> RCS file: /cvsroot/src/sys/uvm/uvm_swap.c,v
> retrieving revision 1.139
> diff -u -u -r1.139 uvm_swap.c
> --- uvm/uvm_swap.c      29 May 2008 14:51:27 -0000      1.139
> +++ uvm/uvm_swap.c      28 Aug 2008 15:52:35 -0000
> @@ -1073,6 +1073,55 @@
>         return (0);
> }
>
> +void
> +uvm_swap_shutdown(struct lwp *l)
> +{
> +       struct swapdev *sdp;
> +       struct swappri *spp;
> +       struct vnode *vp;
> +       int error;
> +
> +       printf("turning of swap...");
> +       rw_enter(&swap_syscall_lock, RW_WRITER);
> +       mutex_enter(&uvm_swap_data_lock);
> +again:
> +       LIST_FOREACH(spp, &swap_priority, spi_swappri)
> +               CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) {
> +                       if (sdp->swd_flags & SWF_FAKE)
> +                               continue;
> +                       if ((sdp->swd_flags & (SWF_INUSE|SWF_ENABLE)) == 0)
> +                               continue;
> +#ifdef DEBUG
> +                       printf("\nturning off swap on %s...",
> +                           sdp->swd_path);
> +#endif
> +                       if (vn_lock(vp = sdp->swd_vp, LK_EXCLUSIVE)) {
> +                               error = EBUSY;
> +                               vp = NULL;
> +                       } else
> +                               error = 0;
> +                       if (!error) {
> +                               error = swap_off(l, sdp);
> +                               mutex_enter(&uvm_swap_data_lock);
> +                       }
> +                       if (error) {
> +                               printf("stopping swap on %s failed "
> +                                   "with error %d\n", sdp->swd_path, error);
> +                               CIRCLEQ_REMOVE(&spp->spi_swapdev, sdp,
> +                                   swd_next);
> +                               uvmexp.nswapdev--;
> +                               swaplist_trim();
> +                               if (vp)
> +                                       vput(vp);
> +                       }
> +                       goto again;
> +               }
> +       printf(" done\n");
> +       mutex_exit(&uvm_swap_data_lock);
> +       rw_exit(&swap_syscall_lock);
> +}
> +
> +
> /*
>  * /dev/drum interface and i/o functions
>  */
> Index: uvm/uvm_swap.h
> ===================================================================
> RCS file: /cvsroot/src/sys/uvm/uvm_swap.h,v
> retrieving revision 1.17
> diff -u -u -r1.17 uvm_swap.h
> --- uvm/uvm_swap.h      29 May 2008 14:51:27 -0000      1.17
> +++ uvm/uvm_swap.h      28 Aug 2008 15:52:35 -0000
> @@ -39,6 +39,7 @@
> #endif
>
> struct swapent;
> +struct lwp;
>
> #if defined(VMSWAP)
> int     uvm_swap_get(struct vm_page *, int, int);
> @@ -51,6 +52,7 @@
> #define uvm_swapisfull()        true
> #endif /* defined(VMSWAP) */
> void    uvm_swap_stats(int, struct swapent *, int, register_t *);
> +void   uvm_swap_shutdown(struct lwp *);
>
> #endif /* _KERNEL */