linux/mm/damon/paddr.c
SeongJae Park 198f0f4c58 mm/damon/vaddr,paddr: support pageout prioritization
This makes the default monitoring primitives for virtual address spaces
and the physical address sapce to support memory regions prioritization
for 'PAGEOUT' DAMOS action.  It calculates hotness of each region as
weighted sum of 'nr_accesses' and 'age' of the region and get the
priority score as reverse of the hotness, so that cold regions can be
paged out first.

Link: https://lkml.kernel.org/r/20211019150731.16699-9-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 Rientjes <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>
2021-11-06 13:30:45 -07:00

274 lines
5.9 KiB
C

// 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 <linux/swap.h>
#include "../internal.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;
}
int damon_pa_apply_scheme(struct damon_ctx *ctx, struct damon_target *t,
struct damon_region *r, struct damos *scheme)
{
unsigned long addr;
LIST_HEAD(page_list);
if (scheme->action != DAMOS_PAGEOUT)
return -EINVAL;
for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
struct page *page = damon_get_page(PHYS_PFN(addr));
if (!page)
continue;
ClearPageReferenced(page);
test_and_clear_page_young(page);
if (isolate_lru_page(page)) {
put_page(page);
continue;
}
if (PageUnevictable(page)) {
putback_lru_page(page);
} else {
list_add(&page->lru, &page_list);
put_page(page);
}
}
reclaim_pages(&page_list);
cond_resched();
return 0;
}
int damon_pa_scheme_score(struct damon_ctx *context, struct damon_target *t,
struct damon_region *r, struct damos *scheme)
{
switch (scheme->action) {
case DAMOS_PAGEOUT:
return damon_pageout_score(context, r, scheme);
default:
break;
}
return DAMOS_MAX_SCORE;
}
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 = damon_pa_apply_scheme;
ctx->primitive.get_scheme_score = damon_pa_scheme_score;
}