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authorLinus Torvalds <torvalds@linux-foundation.org>2020-02-05 17:44:14 +0000
committerLinus Torvalds <torvalds@linux-foundation.org>2020-02-05 17:44:14 +0000
commitd271ab29230b1d0ceb426f374c221c4eb2c91c64 (patch)
tree9c97e0196c5c1bab8bfbee95a052dbfd0fd0d6d2 /drivers/block
parent2634744bf38ab20d17fe8220f1f83b6f3801386f (diff)
parent8557bbe5156e5fba022d5a5220004b1e016227ee (diff)
Merge tag 'for-linus-5.6-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross: - fix a bug introduced in 5.5 in the Xen gntdev driver - fix the Xen balloon driver when running on ancient Xen versions - allow Xen stubdoms to control interrupt enable flags of passed-through PCI cards - release resources in Xen backends under memory pressure * tag 'for-linus-5.6-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/blkback: Consistently insert one empty line between functions xen/blkback: Remove unnecessary static variable name prefixes xen/blkback: Squeeze page pools if a memory pressure is detected xenbus/backend: Protect xenbus callback with lock xenbus/backend: Add memory pressure handler callback xen/gntdev: Do not use mm notifiers with autotranslating guests xen/balloon: Support xend-based toolstack take two xen-pciback: optionally allow interrupt enable flag writes
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/xen-blkback/blkback.c42
-rw-r--r--drivers/block/xen-blkback/common.h1
-rw-r--r--drivers/block/xen-blkback/xenbus.c26
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)