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authorSeongJae Park <sj@kernel.org>2021-11-05 13:46:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 13:30:45 -0700
commita28397beb55b68bd0f15c6778540e8ae1bc26d21 (patch)
treecb24e7ee0a191b0fee153b740a2b245aefbef276 /mm/damon
parent46c3a0accdc48c86928157fd073e66807f338485 (diff)
downloadlinux-a28397beb55b68bd0f15c6778540e8ae1bc26d21.tar.bz2
mm/damon: implement primitives for physical address space monitoring
This implements the monitoring primitives for the physical memory address space. Internally, it uses the PTE Accessed bit, similar to that of the virtual address spaces monitoring primitives. It supports only user memory pages, as idle pages tracking does. If the monitoring target physical memory address range contains non-user memory pages, access check of the pages will do nothing but simply treat the pages as not accessed. Link: https://lkml.kernel.org/r/20211012205711.29216-6-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: Brendan Higgins <brendanhiggins@google.com> 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> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/damon')
-rw-r--r--mm/damon/Kconfig8
-rw-r--r--mm/damon/Makefile1
-rw-r--r--mm/damon/paddr.c224
3 files changed, 233 insertions, 0 deletions
diff --git a/mm/damon/Kconfig b/mm/damon/Kconfig
index ba8898c7eb8e..2a5923be631e 100644
--- a/mm/damon/Kconfig
+++ b/mm/damon/Kconfig
@@ -32,6 +32,14 @@ config DAMON_VADDR
This builds the default data access monitoring primitives for DAMON
that work for virtual address spaces.
+config DAMON_PADDR
+ bool "Data access monitoring primitives for the physical address space"
+ depends on DAMON && MMU
+ select PAGE_IDLE_FLAG
+ help
+ This builds the default data access monitoring primitives for DAMON
+ that works for the physical address space.
+
config DAMON_VADDR_KUNIT_TEST
bool "Test for DAMON primitives" if !KUNIT_ALL_TESTS
depends on DAMON_VADDR && KUNIT=y
diff --git a/mm/damon/Makefile b/mm/damon/Makefile
index 99b1bfe01ff5..8d9b0df79702 100644
--- a/mm/damon/Makefile
+++ b/mm/damon/Makefile
@@ -2,4 +2,5 @@
obj-$(CONFIG_DAMON) := core.o
obj-$(CONFIG_DAMON_VADDR) += prmtv-common.o vaddr.o
+obj-$(CONFIG_DAMON_PADDR) += prmtv-common.o paddr.o
obj-$(CONFIG_DAMON_DBGFS) += dbgfs.o
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
new file mode 100644
index 000000000000..d7a2ecd09ed0
--- /dev/null
+++ b/mm/damon/paddr.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DAMON Primitives for The Physical Address Space
+ *
+ * Author: SeongJae Park <sj@kernel.org>
+ */
+
+#define pr_fmt(fmt) "damon-pa: " fmt
+
+#include <linux/mmu_notifier.h>
+#include <linux/page_idle.h>
+#include <linux/pagemap.h>
+#include <linux/rmap.h>
+
+#include "prmtv-common.h"
+
+static bool __damon_pa_mkold(struct page *page, struct vm_area_struct *vma,
+ unsigned long addr, void *arg)
+{
+ struct page_vma_mapped_walk pvmw = {
+ .page = page,
+ .vma = vma,
+ .address = addr,
+ };
+
+ while (page_vma_mapped_walk(&pvmw)) {
+ addr = pvmw.address;
+ if (pvmw.pte)
+ damon_ptep_mkold(pvmw.pte, vma->vm_mm, addr);
+ else
+ damon_pmdp_mkold(pvmw.pmd, vma->vm_mm, addr);
+ }
+ return true;
+}
+
+static void damon_pa_mkold(unsigned long paddr)
+{
+ struct page *page = damon_get_page(PHYS_PFN(paddr));
+ struct rmap_walk_control rwc = {
+ .rmap_one = __damon_pa_mkold,
+ .anon_lock = page_lock_anon_vma_read,
+ };
+ bool need_lock;
+
+ if (!page)
+ return;
+
+ if (!page_mapped(page) || !page_rmapping(page)) {
+ set_page_idle(page);
+ goto out;
+ }
+
+ need_lock = !PageAnon(page) || PageKsm(page);
+ if (need_lock && !trylock_page(page))
+ goto out;
+
+ rmap_walk(page, &rwc);
+
+ if (need_lock)
+ unlock_page(page);
+
+out:
+ put_page(page);
+}
+
+static void __damon_pa_prepare_access_check(struct damon_ctx *ctx,
+ struct damon_region *r)
+{
+ r->sampling_addr = damon_rand(r->ar.start, r->ar.end);
+
+ damon_pa_mkold(r->sampling_addr);
+}
+
+void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
+{
+ struct damon_target *t;
+ struct damon_region *r;
+
+ damon_for_each_target(t, ctx) {
+ damon_for_each_region(r, t)
+ __damon_pa_prepare_access_check(ctx, r);
+ }
+}
+
+struct damon_pa_access_chk_result {
+ unsigned long page_sz;
+ bool accessed;
+};
+
+static bool __damon_pa_young(struct page *page, struct vm_area_struct *vma,
+ unsigned long addr, void *arg)
+{
+ struct damon_pa_access_chk_result *result = arg;
+ struct page_vma_mapped_walk pvmw = {
+ .page = page,
+ .vma = vma,
+ .address = addr,
+ };
+
+ result->accessed = false;
+ result->page_sz = PAGE_SIZE;
+ while (page_vma_mapped_walk(&pvmw)) {
+ addr = pvmw.address;
+ if (pvmw.pte) {
+ result->accessed = pte_young(*pvmw.pte) ||
+ !page_is_idle(page) ||
+ mmu_notifier_test_young(vma->vm_mm, addr);
+ } else {
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ result->accessed = pmd_young(*pvmw.pmd) ||
+ !page_is_idle(page) ||
+ mmu_notifier_test_young(vma->vm_mm, addr);
+ result->page_sz = ((1UL) << HPAGE_PMD_SHIFT);
+#else
+ WARN_ON_ONCE(1);
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+ }
+ if (result->accessed) {
+ page_vma_mapped_walk_done(&pvmw);
+ break;
+ }
+ }
+
+ /* If accessed, stop walking */
+ return !result->accessed;
+}
+
+static bool damon_pa_young(unsigned long paddr, unsigned long *page_sz)
+{
+ struct page *page = damon_get_page(PHYS_PFN(paddr));
+ struct damon_pa_access_chk_result result = {
+ .page_sz = PAGE_SIZE,
+ .accessed = false,
+ };
+ struct rmap_walk_control rwc = {
+ .arg = &result,
+ .rmap_one = __damon_pa_young,
+ .anon_lock = page_lock_anon_vma_read,
+ };
+ bool need_lock;
+
+ if (!page)
+ return false;
+
+ if (!page_mapped(page) || !page_rmapping(page)) {
+ if (page_is_idle(page))
+ result.accessed = false;
+ else
+ result.accessed = true;
+ put_page(page);
+ goto out;
+ }
+
+ need_lock = !PageAnon(page) || PageKsm(page);
+ if (need_lock && !trylock_page(page)) {
+ put_page(page);
+ return NULL;
+ }
+
+ rmap_walk(page, &rwc);
+
+ if (need_lock)
+ unlock_page(page);
+ put_page(page);
+
+out:
+ *page_sz = result.page_sz;
+ return result.accessed;
+}
+
+static void __damon_pa_check_access(struct damon_ctx *ctx,
+ struct damon_region *r)
+{
+ static unsigned long last_addr;
+ static unsigned long last_page_sz = PAGE_SIZE;
+ static bool last_accessed;
+
+ /* If the region is in the last checked page, reuse the result */
+ if (ALIGN_DOWN(last_addr, last_page_sz) ==
+ ALIGN_DOWN(r->sampling_addr, last_page_sz)) {
+ if (last_accessed)
+ r->nr_accesses++;
+ return;
+ }
+
+ last_accessed = damon_pa_young(r->sampling_addr, &last_page_sz);
+ if (last_accessed)
+ r->nr_accesses++;
+
+ last_addr = r->sampling_addr;
+}
+
+unsigned int damon_pa_check_accesses(struct damon_ctx *ctx)
+{
+ struct damon_target *t;
+ struct damon_region *r;
+ unsigned int max_nr_accesses = 0;
+
+ damon_for_each_target(t, ctx) {
+ damon_for_each_region(r, t) {
+ __damon_pa_check_access(ctx, r);
+ max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
+ }
+ }
+
+ return max_nr_accesses;
+}
+
+bool damon_pa_target_valid(void *t)
+{
+ return true;
+}
+
+void damon_pa_set_primitives(struct damon_ctx *ctx)
+{
+ ctx->primitive.init = NULL;
+ ctx->primitive.update = NULL;
+ ctx->primitive.prepare_access_checks = damon_pa_prepare_access_checks;
+ ctx->primitive.check_accesses = damon_pa_check_accesses;
+ ctx->primitive.reset_aggregated = NULL;
+ ctx->primitive.target_valid = damon_pa_target_valid;
+ ctx->primitive.cleanup = NULL;
+ ctx->primitive.apply_scheme = NULL;
+}