[patch 225/262] mm/damon/vaddr: support DAMON-based Operation Schemes

Andrew Morton
2021-11-05T20:46:32Z

From: SeongJae Park <sj@kernel.org>
Subject: mm/damon/vaddr: support DAMON-based Operation Schemes

This commit makes DAMON's default primitives for virtual address spaces to
support DAMON-based Operation Schemes (DAMOS) by implementing actions
application functions and registering it to the monitoring context. The
implementation simply links 'madvise()' for related DAMOS actions. That
is, 'madvise(MADV_WILLNEED)' is called for 'WILLNEED' DAMOS action and
similar for other actions ('COLD', 'PAGEOUT', 'HUGEPAGE', 'NOHUGEPAGE').

So, the kernel space DAMON users can now use the DAMON-based optimizations
with only small amount of code.

Link: https://lkml.kernel.org/r/20211001125604.29660-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rienjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

include/linux/damon.h | 2 +
mm/damon/vaddr.c | 56 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 58 insertions(+)

--- a/include/linux/damon.h~mm-damon-vaddr-support-damon-based-operation-schemes
+++ a/include/linux/damon.h
@@ -337,6 +337,8 @@ void damon_va_prepare_access_checks(stru
unsigned int damon_va_check_accesses(struct damon_ctx *ctx);
bool damon_va_target_valid(void *t);
void damon_va_cleanup(struct damon_ctx *ctx);
+int damon_va_apply_scheme(struct damon_ctx *context, struct damon_target *t,
+ struct damon_region *r, struct damos *scheme);
void damon_va_set_primitives(struct damon_ctx *ctx);

#endif /* CONFIG_DAMON_VADDR */
--- a/mm/damon/vaddr.c~mm-damon-vaddr-support-damon-based-operation-schemes
+++ a/mm/damon/vaddr.c
@@ -7,6 +7,7 @@

#define pr_fmt(fmt) "damon-va: " fmt

+#include <asm-generic/mman-common.h>
#include <linux/damon.h>
#include <linux/hugetlb.h>
#include <linux/mm.h>
@@ -658,6 +659,60 @@ bool damon_va_target_valid(void *target)
return false;
}

+#ifndef CONFIG_ADVISE_SYSCALLS
+static int damos_madvise(struct damon_target *target, struct damon_region *r,
+ int behavior)
+{
+ return -EINVAL;
+}
+#else
+static int damos_madvise(struct damon_target *target, struct damon_region *r,
+ int behavior)
+{
+ struct mm_struct *mm;
+ int ret = -ENOMEM;
+
+ mm = damon_get_mm(target);
+ if (!mm)
+ goto out;
+
+ ret = do_madvise(mm, PAGE_ALIGN(r->ar.start),
+ PAGE_ALIGN(r->ar.end - r->ar.start), behavior);
+ mmput(mm);
+out:
+ return ret;
+}
+#endif /* CONFIG_ADVISE_SYSCALLS */
+
+int damon_va_apply_scheme(struct damon_ctx *ctx, struct damon_target *t,
+ struct damon_region *r, struct damos *scheme)
+{
+ int madv_action;
+
+ switch (scheme->action) {
+ case DAMOS_WILLNEED:
+ madv_action = MADV_WILLNEED;
+ break;
+ case DAMOS_COLD:
+ madv_action = MADV_COLD;
+ break;
+ case DAMOS_PAGEOUT:
+ madv_action = MADV_PAGEOUT;
+ break;
+ case DAMOS_HUGEPAGE:
+ madv_action = MADV_HUGEPAGE;
+ break;
+ case DAMOS_NOHUGEPAGE:
+ madv_action = MADV_NOHUGEPAGE;
+ break;
+ default:
+ pr_warn("Wrong action %d\n", scheme->action);
+ return -EINVAL;
+ }
+
+ return damos_madvise(t, r, madv_action);
+}
+
void damon_va_set_primitives(struct damon_ctx *ctx)
{
ctx->primitive.init = damon_va_init;
@@ -667,6 +722,7 @@ void damon_va_set_primitives(struct damo
ctx->primitive.reset_aggregated = NULL;
ctx->primitive.target_valid = damon_va_target_valid;
ctx->primitive.cleanup = NULL;
+ ctx->primitive.apply_scheme = damon_va_apply_scheme;
}

#include "vaddr-test.h"
_