From: Jonathan Brassow <jbrassow@xxxxxxxxxx> Allow the device-mapper log's 'mark' and 'clear' requests to be grouped and processed in a batch. This can significantly reduce the amount of traffic going between the kernel and userspace (where the processing daemon resides). Signed-off-by: Jonathan Brassow <jbrassow@xxxxxxxxxx> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> --- drivers/md/dm-log-userspace-base.c | 102 ++++++++++++++++++++++++++++-------- 1 files changed, 79 insertions(+), 23 deletions(-) diff --git a/drivers/md/dm-log-userspace-base.c b/drivers/md/dm-log-userspace-base.c index fb71c51..3be0687 100644 --- a/drivers/md/dm-log-userspace-base.c +++ b/drivers/md/dm-log-userspace-base.c @@ -18,6 +18,14 @@ struct flush_entry { struct list_head list; }; +/* + * This limit on the number of mark and clear request is, to a degree, + * arbitrary. However, there is some basis for the choice in the limits + * imposed on the size of data payload by dm-log-userspace-transfer.c: + * dm_consult_userspace(). + */ +#define MAX_FLUSH_GROUP_COUNT 32 + struct log_c { struct dm_target *ti; uint32_t region_size; @@ -349,6 +357,71 @@ static int userspace_in_sync(struct dm_dirty_log *log, region_t region, return (r) ? 0 : (int)in_sync; } +static int flush_one_by_one(struct log_c *lc, struct list_head *flush_list) +{ + int r = 0; + struct flush_entry *fe; + + list_for_each_entry(fe, flush_list, list) { + r = userspace_do_request(lc, lc->uuid, fe->type, + (char *)&fe->region, + sizeof(fe->region), + NULL, NULL); + if (r) + break; + } + + return r; +} + +static int flush_by_group(struct log_c *lc, struct list_head *flush_list) +{ + int r = 0; + int count; + uint32_t type = 0; + struct flush_entry *fe, *tmp_fe; + LIST_HEAD(tmp_list); + uint64_t group[MAX_FLUSH_GROUP_COUNT]; + + /* + * Group process the requests + */ + while (!list_empty(flush_list)) { + count = 0; + + list_for_each_entry_safe(fe, tmp_fe, flush_list, list) { + group[count] = fe->region; + count++; + + list_del(&fe->list); + list_add(&fe->list, &tmp_list); + + type = fe->type; + if (count >= MAX_FLUSH_GROUP_COUNT) + break; + } + + r = userspace_do_request(lc, lc->uuid, type, + (char *)(group), + count * sizeof(uint64_t), + NULL, NULL); + if (r) { + /* Group send failed. Attempt one-by-one. */ + list_splice_init(&tmp_list, flush_list); + r = flush_one_by_one(lc, flush_list); + break; + } + } + + /* + * Must collect flush_entrys that were successfully processed + * as a group so that they will be free'd by the caller. + */ + list_splice_init(&tmp_list, flush_list); + + return r; +} + /* * userspace_flush * @@ -383,30 +456,13 @@ static int userspace_flush(struct dm_dirty_log *log) if (list_empty(&mark_list) && list_empty(&clear_list)) return 0; - /* - * FIXME: Count up requests, group request types, - * allocate memory to stick all requests in and - * send to server in one go. Failing the allocation, - * do it one by one. - */ - - list_for_each_entry(fe, &mark_list, list) { - r = userspace_do_request(lc, lc->uuid, fe->type, - (char *)&fe->region, - sizeof(fe->region), - NULL, NULL); - if (r) - goto fail; - } + r = flush_by_group(lc, &mark_list); + if (r) + goto fail; - list_for_each_entry(fe, &clear_list, list) { - r = userspace_do_request(lc, lc->uuid, fe->type, - (char *)&fe->region, - sizeof(fe->region), - NULL, NULL); - if (r) - goto fail; - } + r = flush_by_group(lc, &clear_list); + if (r) + goto fail; r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH, NULL, 0, NULL, NULL); -- 1.7.2.3 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel