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

[Warner Losh]

The branch main has been updated by imp:

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

commit d09ee08f106ddabeb02affc7e9dcfea8c154a57d
Author:     Warner Losh <i...@freebsd.org>
AuthorDate: 2024-05-24 14:32:47 +0000
Commit:     Warner Losh <i...@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");
 }