[lustre-devel] [PATCH 03/21] lustre: obdclass: use list_sort() to sort a list.
Andreas Dilger
adilger at whamcloud.com
Thu Feb 7 16:13:50 PST 2019
On Feb 6, 2019, at 17:03, NeilBrown <neilb at suse.com> wrote:
>
> Rather than a bespoke bubble-sort, use list_sort() to
> sort this linked list.
>
> Signed-off-by: NeilBrown <neilb at suse.com>
Probably a performance win as well, since it looks like list_sort() uses merge sort
instead of bubble sort.
Reviewed-by: Andreas Dilger <adilger at whamcloud.com>
> ---
> drivers/staging/lustre/lustre/obdclass/cl_io.c | 51 +++++-------------------
> 1 file changed, 10 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/staging/lustre/lustre/obdclass/cl_io.c b/drivers/staging/lustre/lustre/obdclass/cl_io.c
> index beac7e8bc92a..7bf02350f19d 100644
> --- a/drivers/staging/lustre/lustre/obdclass/cl_io.c
> +++ b/drivers/staging/lustre/lustre/obdclass/cl_io.c
> @@ -42,6 +42,7 @@
> #include <obd_support.h>
> #include <lustre_fid.h>
> #include <linux/list.h>
> +#include <linux/list_sort.h>
> #include <linux/sched.h>
> #include <cl_object.h>
> #include "cl_internal.h"
> @@ -213,9 +214,15 @@ int cl_io_rw_init(const struct lu_env *env, struct cl_io *io,
> }
> EXPORT_SYMBOL(cl_io_rw_init);
>
> -static int cl_lock_descr_sort(const struct cl_lock_descr *d0,
> - const struct cl_lock_descr *d1)
> +static int cl_lock_descr_cmp(void *priv,
> + struct list_head *a, struct list_head *b)
> {
> + const struct cl_io_lock_link *l0 = list_entry(a, struct cl_io_lock_link, cill_linkage);
> + const struct cl_io_lock_link *l1 = list_entry(b, struct cl_io_lock_link, cill_linkage);
> +
> + const struct cl_lock_descr *d0 = &l0->cill_descr;
> + const struct cl_lock_descr *d1 = &l1->cill_descr;
> +
> return lu_fid_cmp(lu_object_fid(&d0->cld_obj->co_lu),
> lu_object_fid(&d1->cld_obj->co_lu));
> }
> @@ -225,45 +232,7 @@ static int cl_lock_descr_sort(const struct cl_lock_descr *d0,
> */
> static void cl_io_locks_sort(struct cl_io *io)
> {
> - int done = 0;
> -
> - /* hidden treasure: bubble sort for now. */
> - do {
> - struct cl_io_lock_link *curr;
> - struct cl_io_lock_link *prev;
> - struct cl_io_lock_link *temp;
> -
> - done = 1;
> - prev = NULL;
> -
> - list_for_each_entry_safe(curr, temp,
> - &io->ci_lockset.cls_todo,
> - cill_linkage) {
> - if (prev) {
> - switch (cl_lock_descr_sort(&prev->cill_descr,
> - &curr->cill_descr)) {
> - case 0:
> - /*
> - * IMPOSSIBLE: Identical locks are
> - * already removed at
> - * this point.
> - */
> - default:
> - LBUG();
> - case 1:
> - list_move_tail(&curr->cill_linkage,
> - &prev->cill_linkage);
> - done = 0;
> - continue; /* don't change prev: it's
> - * still "previous"
> - */
> - case -1: /* already in order */
> - break;
> - }
> - }
> - prev = curr;
> - }
> - } while (!done);
> + list_sort(NULL, &io->ci_lockset.cls_todo, cl_lock_descr_cmp);
> }
>
> static void cl_lock_descr_merge(struct cl_lock_descr *d0,
>
>
Cheers, Andreas
---
Andreas Dilger
Principal Lustre Architect
Whamcloud
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