git: d09ee08f106d - main - nvme: Count number of alginment splits

The branch main has been updated by imp:

URL: https://cgit.FreeBSD.org/src/commit/?id=d09ee08f106ddabeb02affc7e9dcfea8c154a57d

commit d09ee08f106ddabeb02affc7e9dcfea8c154a57d
Author:     Warner Losh <imp@FreeBSD.org>
AuthorDate: 2024-05-24 14:32:47 +0000
Commit:     Warner Losh <imp@FreeBSD.org>
CommitDate: 2024-05-24 14:32:47 +0000

    nvme: Count number of alginment splits
    
    When possible, we split up I/Os to NVMe drives that advertise a
    preferred alignment. Add a counter for this.
    
    Sponsored by:           Netflix
    Reviewed by:            chuck, mav
    Differential Revision:  https://reviews.freebsd.org/D45311
---
 sys/dev/nvme/nvme_ctrlr.c   | 5 +++++
 sys/dev/nvme/nvme_ns.c      | 1 +
 sys/dev/nvme/nvme_private.h | 4 ++++
 sys/dev/nvme/nvme_sysctl.c  | 5 +++++
 4 files changed, 15 insertions(+)

diff --git a/sys/dev/nvme/nvme_ctrlr.c b/sys/dev/nvme/nvme_ctrlr.c
index 00e619bfdc46..d9bd1fce2864 100644
--- a/sys/dev/nvme/nvme_ctrlr.c
+++ b/sys/dev/nvme/nvme_ctrlr.c
@@ -1442,6 +1442,8 @@ nvme_ctrlr_construct(struct nvme_controller *ctrlr, device_t dev)
 	ctrlr->enable_aborts = 0;
 	TUNABLE_INT_FETCH("hw.nvme.enable_aborts", &ctrlr->enable_aborts);
 
+	ctrlr->alignment_splits = counter_u64_alloc(M_WAITOK);
+
 	/* Cap transfers by the maximum addressable by page-sized PRP (4KB pages -> 2MB). */
 	ctrlr->max_xfer_size = MIN(maxphys, (ctrlr->page_size / 8 * ctrlr->page_size));
 	if (nvme_ctrlr_construct_admin_qpair(ctrlr) != 0)
@@ -1560,6 +1562,9 @@ noadminq:
 	    ctrlr->resource_id, ctrlr->resource);
 
 nores:
+	if (ctrlr->alignment_splits)
+		counter_u64_free(ctrlr->alignment_splits);
+
 	mtx_destroy(&ctrlr->lock);
 }
 
diff --git a/sys/dev/nvme/nvme_ns.c b/sys/dev/nvme/nvme_ns.c
index e494b8cd857a..201cf9188c1e 100644
--- a/sys/dev/nvme/nvme_ns.c
+++ b/sys/dev/nvme/nvme_ns.c
@@ -428,6 +428,7 @@ nvme_ns_split_bio(struct nvme_namespace *ns, struct bio *bp,
 	if (child_bios == NULL)
 		return (ENOMEM);
 
+	counter_u64_add(ns->ctrlr->alignment_splits, 1);
 	for (i = 0; i < num_bios; i++) {
 		child = child_bios[i];
 		err = nvme_ns_bio_process(ns, child, nvme_bio_child_done);
diff --git a/sys/dev/nvme/nvme_private.h b/sys/dev/nvme/nvme_private.h
index 69141add4e48..8415819ca20b 100644
--- a/sys/dev/nvme/nvme_private.h
+++ b/sys/dev/nvme/nvme_private.h
@@ -32,6 +32,7 @@
 #include <sys/param.h>
 #include <sys/bio.h>
 #include <sys/bus.h>
+#include <sys/counter.h>
 #include <sys/kernel.h>
 #include <sys/lock.h>
 #include <sys/malloc.h>
@@ -317,6 +318,9 @@ struct nvme_controller {
 	bus_dmamap_t			hmb_desc_map;
 	struct nvme_hmb_desc		*hmb_desc_vaddr;
 	uint64_t			hmb_desc_paddr;
+
+	/* Statistics */
+	counter_u64_t			alignment_splits;
 };
 
 #define nvme_mmio_offsetof(reg)						       \
diff --git a/sys/dev/nvme/nvme_sysctl.c b/sys/dev/nvme/nvme_sysctl.c
index d6452a2e5492..447f48e0bdd5 100644
--- a/sys/dev/nvme/nvme_sysctl.c
+++ b/sys/dev/nvme/nvme_sysctl.c
@@ -30,6 +30,7 @@
 #include "opt_nvme.h"
 
 #include <sys/param.h>
+#include <sys/systm.h>
 #include <sys/bus.h>
 #include <sys/sysctl.h>
 
@@ -419,4 +420,8 @@ nvme_sysctl_initialize_ctrlr(struct nvme_controller *ctrlr)
 		nvme_sysctl_initialize_queue(&ctrlr->ioq[i], ctrlr_ctx,
 		    que_tree);
 	}
+
+	SYSCTL_ADD_COUNTER_U64(ctrlr_ctx, ctrlr_list, OID_AUTO, "alignment_splits",
+	    CTLFLAG_RD, &ctrlr->alignment_splits,
+	    "Number of times we split the I/O alignment for drives with preferred alignment");
 }