diff options
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 42 | ||||
| -rw-r--r-- | drivers/block/xen-blkback/common.h | 1 | ||||
| -rw-r--r-- | drivers/block/xen-blkback/xenbus.c | 26 |
3 files changed, 44 insertions, 25 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 716b99aa2307..c2f71265af4b 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -62,8 +62,8 @@ * IO workloads. */ -static int xen_blkif_max_buffer_pages = 1024; -module_param_named(max_buffer_pages, xen_blkif_max_buffer_pages, int, 0644); +static int max_buffer_pages = 1024; +module_param_named(max_buffer_pages, max_buffer_pages, int, 0644); MODULE_PARM_DESC(max_buffer_pages, "Maximum number of free pages to keep in each block backend buffer"); @@ -78,8 +78,8 @@ MODULE_PARM_DESC(max_buffer_pages, * algorithm. */ -static int xen_blkif_max_pgrants = 1056; -module_param_named(max_persistent_grants, xen_blkif_max_pgrants, int, 0644); +static int max_pgrants = 1056; +module_param_named(max_persistent_grants, max_pgrants, int, 0644); MODULE_PARM_DESC(max_persistent_grants, "Maximum number of grants to map persistently"); @@ -88,8 +88,8 @@ MODULE_PARM_DESC(max_persistent_grants, * use. The time is in seconds, 0 means indefinitely long. */ -static unsigned int xen_blkif_pgrant_timeout = 60; -module_param_named(persistent_grant_unused_seconds, xen_blkif_pgrant_timeout, +static unsigned int pgrant_timeout = 60; +module_param_named(persistent_grant_unused_seconds, pgrant_timeout, uint, 0644); MODULE_PARM_DESC(persistent_grant_unused_seconds, "Time in seconds an unused persistent grant is allowed to " @@ -137,9 +137,8 @@ module_param(log_stats, int, 0644); static inline bool persistent_gnt_timeout(struct persistent_gnt *persistent_gnt) { - return xen_blkif_pgrant_timeout && - (jiffies - persistent_gnt->last_used >= - HZ * xen_blkif_pgrant_timeout); + return pgrant_timeout && (jiffies - persistent_gnt->last_used >= + HZ * pgrant_timeout); } static inline int get_free_page(struct xen_blkif_ring *ring, struct page **page) @@ -234,7 +233,7 @@ static int add_persistent_gnt(struct xen_blkif_ring *ring, struct persistent_gnt *this; struct xen_blkif *blkif = ring->blkif; - if (ring->persistent_gnt_c >= xen_blkif_max_pgrants) { + if (ring->persistent_gnt_c >= max_pgrants) { if (!blkif->vbd.overflow_max_grants) blkif->vbd.overflow_max_grants = 1; return -EBUSY; @@ -397,14 +396,13 @@ static void purge_persistent_gnt(struct xen_blkif_ring *ring) goto out; } - if (ring->persistent_gnt_c < xen_blkif_max_pgrants || - (ring->persistent_gnt_c == xen_blkif_max_pgrants && + if (ring->persistent_gnt_c < max_pgrants || + (ring->persistent_gnt_c == max_pgrants && !ring->blkif->vbd.overflow_max_grants)) { num_clean = 0; } else { - num_clean = (xen_blkif_max_pgrants / 100) * LRU_PERCENT_CLEAN; - num_clean = ring->persistent_gnt_c - xen_blkif_max_pgrants + - num_clean; + num_clean = (max_pgrants / 100) * LRU_PERCENT_CLEAN; + num_clean = ring->persistent_gnt_c - max_pgrants + num_clean; num_clean = min(ring->persistent_gnt_c, num_clean); pr_debug("Going to purge at least %u persistent grants\n", num_clean); @@ -599,8 +597,7 @@ static void print_stats(struct xen_blkif_ring *ring) current->comm, ring->st_oo_req, ring->st_rd_req, ring->st_wr_req, ring->st_f_req, ring->st_ds_req, - ring->persistent_gnt_c, - xen_blkif_max_pgrants); + ring->persistent_gnt_c, max_pgrants); ring->st_print = jiffies + msecs_to_jiffies(10 * 1000); ring->st_rd_req = 0; ring->st_wr_req = 0; @@ -656,8 +653,11 @@ purge_gnt_list: ring->next_lru = jiffies + msecs_to_jiffies(LRU_INTERVAL); } - /* Shrink if we have more than xen_blkif_max_buffer_pages */ - shrink_free_pagepool(ring, xen_blkif_max_buffer_pages); + /* Shrink the free pages pool if it is too large. */ + if (time_before(jiffies, blkif->buffer_squeeze_end)) + shrink_free_pagepool(ring, 0); + else + shrink_free_pagepool(ring, max_buffer_pages); if (log_stats && time_after(jiffies, ring->st_print)) print_stats(ring); @@ -884,7 +884,7 @@ again: continue; } if (use_persistent_gnts && - ring->persistent_gnt_c < xen_blkif_max_pgrants) { + ring->persistent_gnt_c < max_pgrants) { /* * We are using persistent grants, the grant is * not mapped but we might have room for it. @@ -911,7 +911,7 @@ again: pages[seg_idx]->persistent_gnt = persistent_gnt; pr_debug("grant %u added to the tree of persistent grants, using %u/%u\n", persistent_gnt->gnt, ring->persistent_gnt_c, - xen_blkif_max_pgrants); + max_pgrants); goto next; } if (use_persistent_gnts && !blkif->vbd.overflow_max_grants) { diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index 49132b0adbbe..a3eeccf3ac5f 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -319,6 +319,7 @@ struct xen_blkif { /* All rings for this device. */ struct xen_blkif_ring *rings; unsigned int nr_rings; + unsigned long buffer_squeeze_end; }; struct seg_buf { diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 4c5d99f87813..42944d41aea0 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -467,7 +467,6 @@ static void xenvbd_sysfs_delif(struct xenbus_device *dev) device_remove_file(&dev->dev, &dev_attr_physical_device); } - static void xen_vbd_free(struct xen_vbd *vbd) { if (vbd->bdev) @@ -524,6 +523,7 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, handle, blkif->domid); return 0; } + static int xen_blkbk_remove(struct xenbus_device *dev) { struct backend_info *be = dev_get_drvdata(&dev->dev); @@ -607,6 +607,7 @@ static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info if (err) dev_warn(&dev->dev, "writing feature-discard (%d)", err); } + int xen_blkbk_barrier(struct xenbus_transaction xbt, struct backend_info *be, int state) { @@ -691,7 +692,6 @@ fail: return err; } - /* * Callback received when the hotplug scripts have placed the physical-device * node. Read it and the mode node, and create a vbd. If the frontend is @@ -783,7 +783,6 @@ static void backend_changed(struct xenbus_watch *watch, } } - /* * Callback received when the frontend's state changes. */ @@ -858,9 +857,27 @@ static void frontend_changed(struct xenbus_device *dev, } } +/* Once a memory pressure is detected, squeeze free page pools for a while. */ +static unsigned int buffer_squeeze_duration_ms = 10; +module_param_named(buffer_squeeze_duration_ms, + buffer_squeeze_duration_ms, int, 0644); +MODULE_PARM_DESC(buffer_squeeze_duration_ms, +"Duration in ms to squeeze pages buffer when a memory pressure is detected"); -/* ** Connection ** */ +/* + * Callback received when the memory pressure is detected. + */ +static void reclaim_memory(struct xenbus_device *dev) +{ + struct backend_info *be = dev_get_drvdata(&dev->dev); + if (!be) + return; + be->blkif->buffer_squeeze_end = jiffies + + msecs_to_jiffies(buffer_squeeze_duration_ms); +} + +/* ** Connection ** */ /* * Write the physical details regarding the block device to the store, and @@ -1152,6 +1169,7 @@ static struct xenbus_driver xen_blkbk_driver = { .remove = xen_blkbk_remove, .otherend_changed = frontend_changed, .allow_rebind = true, + .reclaim_memory = reclaim_memory, }; int xen_blkif_xenbus_init(void) |