git: 0d2224733e97 - main - Implement GET_STACK_USAGE on remaining archs

The branch main has been updated by mhorne:

URL: https://cgit.FreeBSD.org/src/commit/?id=0d2224733e970aaa67a4e1af7b340044adda92f6

commit 0d2224733e970aaa67a4e1af7b340044adda92f6
Author:     Mitchell Horne <mhorne@FreeBSD.org>
AuthorDate: 2021-11-25 16:01:11 +0000
Commit:     Mitchell Horne <mhorne@FreeBSD.org>
CommitDate: 2021-11-30 15:15:56 +0000

    Implement GET_STACK_USAGE on remaining archs
    
    This definition enables callers to estimate remaining space on the
    kstack, and take action on it. Notably, it enables optimizations in the
    GEOM and netgraph subsystems to directly dispatch work items when there
    is sufficient stack space, rather than queuing them for a worker thread.
    
    Implement it for riscv, arm, and mips. Remove the #ifdefs, so it will
    not go unimplemented elsewhere.
    
    PR:             259157
    Reviewed by:    mav, kib, markj (previous version)
    MFC after:      1 week
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D32580
---
 sys/arm/include/proc.h   | 11 +++++++++++
 sys/geom/geom_io.c       |  8 --------
 sys/mips/include/proc.h  | 11 +++++++++++
 sys/netgraph/ng_base.c   |  3 +--
 sys/riscv/include/proc.h | 11 +++++++++++
 5 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/sys/arm/include/proc.h b/sys/arm/include/proc.h
index 641b42280045..5b3b9286363d 100644
--- a/sys/arm/include/proc.h
+++ b/sys/arm/include/proc.h
@@ -72,4 +72,15 @@ struct syscall_args {
 	register_t args[MAXARGS];
 } __aligned(8);
 
+#ifdef _KERNEL
+#include <machine/pcb.h>
+
+/* Get the current kernel thread stack usage. */
+#define	GET_STACK_USAGE(total, used) do {				\
+	struct thread *td = curthread;					\
+	(total) = td->td_kstack_pages * PAGE_SIZE - sizeof(struct pcb);	\
+	(used) = td->td_kstack + (total) - (vm_offset_t)&td;		\
+} while (0)
+
+#endif  /* _KERNEL */
 #endif /* !_MACHINE_PROC_H_ */
diff --git a/sys/geom/geom_io.c b/sys/geom/geom_io.c
index f32a3dc52f93..ce7f6c867388 100644
--- a/sys/geom/geom_io.c
+++ b/sys/geom/geom_io.c
@@ -559,7 +559,6 @@ g_io_request(struct bio *bp, struct g_consumer *cp)
 	atomic_add_int(&cp->nstart, 1);
 #endif
 
-#ifdef GET_STACK_USAGE
 	direct = (cp->flags & G_CF_DIRECT_SEND) != 0 &&
 	    (pp->flags & G_PF_DIRECT_RECEIVE) != 0 &&
 	    !g_is_geom_thread(curthread) &&
@@ -573,9 +572,6 @@ g_io_request(struct bio *bp, struct g_consumer *cp)
 		if (su * 2 > st)
 			direct = 0;
 	}
-#else
-	direct = 0;
-#endif
 
 	if (direct) {
 		error = g_io_check(bp);
@@ -655,7 +651,6 @@ g_io_deliver(struct bio *bp, int error)
 	bp->bio_bcount = bp->bio_length;
 	bp->bio_resid = bp->bio_bcount - bp->bio_completed;
 
-#ifdef GET_STACK_USAGE
 	direct = (pp->flags & G_PF_DIRECT_SEND) &&
 		 (cp->flags & G_CF_DIRECT_RECEIVE) &&
 		 !g_is_geom_thread(curthread);
@@ -666,9 +661,6 @@ g_io_deliver(struct bio *bp, int error)
 		if (su * 2 > st)
 			direct = 0;
 	}
-#else
-	direct = 0;
-#endif
 
 	/*
 	 * The statistics collection is lockless, as such, but we
diff --git a/sys/mips/include/proc.h b/sys/mips/include/proc.h
index 29d832a162e6..5c8bc9d934e0 100644
--- a/sys/mips/include/proc.h
+++ b/sys/mips/include/proc.h
@@ -96,4 +96,15 @@ struct syscall_args {
 #define	KINFO_PROC_SIZE 816
 #endif
 
+#ifdef _KERNEL
+#include <machine/pcb.h>
+
+/* Get the current kernel thread stack usage. */
+#define	GET_STACK_USAGE(total, used) do {				\
+	struct thread *td = curthread;					\
+	(total) = td->td_kstack_pages * PAGE_SIZE - sizeof(struct pcb);	\
+	(used) = td->td_kstack + (total) - (vm_offset_t)&td;		\
+} while (0)
+
+#endif  /* _KERNEL */
 #endif	/* !_MACHINE_PROC_H_ */
diff --git a/sys/netgraph/ng_base.c b/sys/netgraph/ng_base.c
index 655761c2f897..0d64000ee1f5 100644
--- a/sys/netgraph/ng_base.c
+++ b/sys/netgraph/ng_base.c
@@ -2281,7 +2281,7 @@ ng_snd_item(item_p item, int flags)
 		queue = 1;
 	} else {
 		queue = 0;
-#ifdef GET_STACK_USAGE
+
 		/*
 		 * Most of netgraph nodes have small stack consumption and
 		 * for them 25% of free stack space is more than enough.
@@ -2296,7 +2296,6 @@ ng_snd_item(item_p item, int flags)
 		    ((node->nd_flags & NGF_HI_STACK) || (hook &&
 		    (hook->hk_flags & HK_HI_STACK)))))
 			queue = 1;
-#endif
 	}
 
 	if (queue) {
diff --git a/sys/riscv/include/proc.h b/sys/riscv/include/proc.h
index 1c6c8d2919b5..e4ca08574bee 100644
--- a/sys/riscv/include/proc.h
+++ b/sys/riscv/include/proc.h
@@ -53,4 +53,15 @@ struct syscall_args {
 	register_t args[MAXARGS];
 };
 
+#ifdef _KERNEL
+#include <machine/pcb.h>
+
+/* Get the current kernel thread stack usage. */
+#define	GET_STACK_USAGE(total, used) do {				\
+	struct thread *td = curthread;					\
+	(total) = td->td_kstack_pages * PAGE_SIZE - sizeof(struct pcb);	\
+	(used) = td->td_kstack + (total) - (vm_offset_t)&td;		\
+} while (0)
+
+#endif  /* _KERNEL */
 #endif /* !_MACHINE_PROC_H_ */