The branch main has been updated by glebius:
URL:
https://cgit.FreeBSD.org/src/commit/?id=183f8e1e575b526515e70400a22af243cd1a4a78
commit 183f8e1e575b526515e70400a22af243cd1a4a78
Author: Gleb Smirnoff <gleb...@freebsd.org>
AuthorDate: 2021-09-28 18:13:33 +0000
Commit: Gleb Smirnoff <gleb...@freebsd.org>
CommitDate: 2021-09-28 18:23:52 +0000
Externalize nsw_cluster_max and initialize it early.
GEOM_ELI needs to know the value, cause it will soon have special
memory handling for IO operations associated with swap.
Move initialization to swap_pager_init(), which is executed at
SI_SUB_VM, unlike swap_pager_swap_init(), which would be executed
only when a swap is configured. GEOM_ELI might need the value at
SI_SUB_DRIVERS, when disks are tasted by GEOM.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D24400
---
sys/vm/swap_pager.c | 20 +++++++++++++-------
sys/vm/swap_pager.h | 1 +
2 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index 08a5ead438ba..9bc506c9b6b8 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -383,7 +383,7 @@ static int swap_pager_almost_full = 1; /* swap space
exhaustion (w/hysteresis)*/
static struct mtx swbuf_mtx; /* to sync nsw_wcount_async */
static int nsw_wcount_async; /* limit async write buffers */
static int nsw_wcount_async_max;/* assigned maximum */
-static int nsw_cluster_max; /* maximum VOP I/O allowed */
+int nsw_cluster_max; /* maximum VOP I/O allowed */
static int sysctl_swap_async_max(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_vm, OID_AUTO, swap_async_max, CTLTYPE_INT | CTLFLAG_RW |
@@ -572,6 +572,16 @@ swap_pager_init(void)
mtx_init(&sw_dev_mtx, "swapdev", NULL, MTX_DEF);
sx_init(&sw_alloc_sx, "swspsx");
sx_init(&swdev_syscall_lock, "swsysc");
+
+ /*
+ * The nsw_cluster_max is constrained by the bp->b_pages[]
+ * array, which has maxphys / PAGE_SIZE entries, and our locally
+ * defined MAX_PAGEOUT_CLUSTER. Also be aware that swap ops are
+ * constrained by the swap device interleave stripe size.
+ *
+ * Initialized early so that GEOM_ELI can see it.
+ */
+ nsw_cluster_max = min(maxphys / PAGE_SIZE, MAX_PAGEOUT_CLUSTER);
}
/*
@@ -591,11 +601,6 @@ swap_pager_swap_init(void)
* initialize workable values (0 will work for hysteresis
* but it isn't very efficient).
*
- * The nsw_cluster_max is constrained by the bp->b_pages[]
- * array, which has maxphys / PAGE_SIZE entries, and our locally
- * defined MAX_PAGEOUT_CLUSTER. Also be aware that swap ops are
- * constrained by the swap device interleave stripe size.
- *
* Currently we hardwire nsw_wcount_async to 4. This limit is
* designed to prevent other I/O from having high latencies due to
* our pageout I/O. The value 4 works well for one or two active swap
@@ -606,8 +611,9 @@ swap_pager_swap_init(void)
* at least 2 per swap devices, and 4 is a pretty good value if you
* have one NFS swap device due to the command/ack latency over NFS.
* So it all works out pretty well.
+ *
+ * nsw_cluster_max is initialized in swap_pager_init().
*/
- nsw_cluster_max = min(maxphys / PAGE_SIZE, MAX_PAGEOUT_CLUSTER);
nsw_wcount_async = 4;
nsw_wcount_async_max = nsw_wcount_async;
diff --git a/sys/vm/swap_pager.h b/sys/vm/swap_pager.h
index 6761d4f99ee4..20b9bc95b1b2 100644
--- a/sys/vm/swap_pager.h
+++ b/sys/vm/swap_pager.h
@@ -71,6 +71,7 @@ struct swdevt {
#ifdef _KERNEL
extern int swap_pager_avail;
+extern int nsw_cluster_max;
struct xswdev;
int swap_dev_info(int name, struct xswdev *xs, char *devname, size_t len);
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