Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/mm/page_reporting.c b/mm/page_reporting.c
new file mode 100644
index 0000000..cd8e13d
--- /dev/null
+++ b/mm/page_reporting.c
@@ -0,0 +1,364 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/page_reporting.h>
+#include <linux/gfp.h>
+#include <linux/export.h>
+#include <linux/delay.h>
+#include <linux/scatterlist.h>
+
+#include "page_reporting.h"
+#include "internal.h"
+
+#define PAGE_REPORTING_DELAY (2 * HZ)
+static struct page_reporting_dev_info __rcu *pr_dev_info __read_mostly;
+
+enum {
+ PAGE_REPORTING_IDLE = 0,
+ PAGE_REPORTING_REQUESTED,
+ PAGE_REPORTING_ACTIVE
+};
+
+/* request page reporting */
+static void
+__page_reporting_request(struct page_reporting_dev_info *prdev)
+{
+ unsigned int state;
+
+ /* Check to see if we are in desired state */
+ state = atomic_read(&prdev->state);
+ if (state == PAGE_REPORTING_REQUESTED)
+ return;
+
+ /*
+ * If reporting is already active there is nothing we need to do.
+ * Test against 0 as that represents PAGE_REPORTING_IDLE.
+ */
+ state = atomic_xchg(&prdev->state, PAGE_REPORTING_REQUESTED);
+ if (state != PAGE_REPORTING_IDLE)
+ return;
+
+ /*
+ * Delay the start of work to allow a sizable queue to build. For
+ * now we are limiting this to running no more than once every
+ * couple of seconds.
+ */
+ schedule_delayed_work(&prdev->work, PAGE_REPORTING_DELAY);
+}
+
+/* notify prdev of free page reporting request */
+void __page_reporting_notify(void)
+{
+ struct page_reporting_dev_info *prdev;
+
+ /*
+ * We use RCU to protect the pr_dev_info pointer. In almost all
+ * cases this should be present, however in the unlikely case of
+ * a shutdown this will be NULL and we should exit.
+ */
+ rcu_read_lock();
+ prdev = rcu_dereference(pr_dev_info);
+ if (likely(prdev))
+ __page_reporting_request(prdev);
+
+ rcu_read_unlock();
+}
+
+static void
+page_reporting_drain(struct page_reporting_dev_info *prdev,
+ struct scatterlist *sgl, unsigned int nents, bool reported)
+{
+ struct scatterlist *sg = sgl;
+
+ /*
+ * Drain the now reported pages back into their respective
+ * free lists/areas. We assume at least one page is populated.
+ */
+ do {
+ struct page *page = sg_page(sg);
+ int mt = get_pageblock_migratetype(page);
+ unsigned int order = get_order(sg->length);
+
+ __putback_isolated_page(page, order, mt);
+
+ /* If the pages were not reported due to error skip flagging */
+ if (!reported)
+ continue;
+
+ /*
+ * If page was not comingled with another page we can
+ * consider the result to be "reported" since the page
+ * hasn't been modified, otherwise we will need to
+ * report on the new larger page when we make our way
+ * up to that higher order.
+ */
+ if (PageBuddy(page) && buddy_order(page) == order)
+ __SetPageReported(page);
+ } while ((sg = sg_next(sg)));
+
+ /* reinitialize scatterlist now that it is empty */
+ sg_init_table(sgl, nents);
+}
+
+/*
+ * The page reporting cycle consists of 4 stages, fill, report, drain, and
+ * idle. We will cycle through the first 3 stages until we cannot obtain a
+ * full scatterlist of pages, in that case we will switch to idle.
+ */
+static int
+page_reporting_cycle(struct page_reporting_dev_info *prdev, struct zone *zone,
+ unsigned int order, unsigned int mt,
+ struct scatterlist *sgl, unsigned int *offset)
+{
+ struct free_area *area = &zone->free_area[order];
+ struct list_head *list = &area->free_list[mt];
+ unsigned int page_len = PAGE_SIZE << order;
+ struct page *page, *next;
+ long budget;
+ int err = 0;
+
+ /*
+ * Perform early check, if free area is empty there is
+ * nothing to process so we can skip this free_list.
+ */
+ if (list_empty(list))
+ return err;
+
+ spin_lock_irq(&zone->lock);
+
+ /*
+ * Limit how many calls we will be making to the page reporting
+ * device for this list. By doing this we avoid processing any
+ * given list for too long.
+ *
+ * The current value used allows us enough calls to process over a
+ * sixteenth of the current list plus one additional call to handle
+ * any pages that may have already been present from the previous
+ * list processed. This should result in us reporting all pages on
+ * an idle system in about 30 seconds.
+ *
+ * The division here should be cheap since PAGE_REPORTING_CAPACITY
+ * should always be a power of 2.
+ */
+ budget = DIV_ROUND_UP(area->nr_free, PAGE_REPORTING_CAPACITY * 16);
+
+ /* loop through free list adding unreported pages to sg list */
+ list_for_each_entry_safe(page, next, list, lru) {
+ /* We are going to skip over the reported pages. */
+ if (PageReported(page))
+ continue;
+
+ /*
+ * If we fully consumed our budget then update our
+ * state to indicate that we are requesting additional
+ * processing and exit this list.
+ */
+ if (budget < 0) {
+ atomic_set(&prdev->state, PAGE_REPORTING_REQUESTED);
+ next = page;
+ break;
+ }
+
+ /* Attempt to pull page from list and place in scatterlist */
+ if (*offset) {
+ if (!__isolate_free_page(page, order)) {
+ next = page;
+ break;
+ }
+
+ /* Add page to scatter list */
+ --(*offset);
+ sg_set_page(&sgl[*offset], page, page_len, 0);
+
+ continue;
+ }
+
+ /*
+ * Make the first non-reported page in the free list
+ * the new head of the free list before we release the
+ * zone lock.
+ */
+ if (!list_is_first(&page->lru, list))
+ list_rotate_to_front(&page->lru, list);
+
+ /* release lock before waiting on report processing */
+ spin_unlock_irq(&zone->lock);
+
+ /* begin processing pages in local list */
+ err = prdev->report(prdev, sgl, PAGE_REPORTING_CAPACITY);
+
+ /* reset offset since the full list was reported */
+ *offset = PAGE_REPORTING_CAPACITY;
+
+ /* update budget to reflect call to report function */
+ budget--;
+
+ /* reacquire zone lock and resume processing */
+ spin_lock_irq(&zone->lock);
+
+ /* flush reported pages from the sg list */
+ page_reporting_drain(prdev, sgl, PAGE_REPORTING_CAPACITY, !err);
+
+ /*
+ * Reset next to first entry, the old next isn't valid
+ * since we dropped the lock to report the pages
+ */
+ next = list_first_entry(list, struct page, lru);
+
+ /* exit on error */
+ if (err)
+ break;
+ }
+
+ /* Rotate any leftover pages to the head of the freelist */
+ if (&next->lru != list && !list_is_first(&next->lru, list))
+ list_rotate_to_front(&next->lru, list);
+
+ spin_unlock_irq(&zone->lock);
+
+ return err;
+}
+
+static int
+page_reporting_process_zone(struct page_reporting_dev_info *prdev,
+ struct scatterlist *sgl, struct zone *zone)
+{
+ unsigned int order, mt, leftover, offset = PAGE_REPORTING_CAPACITY;
+ unsigned long watermark;
+ int err = 0;
+
+ /* Generate minimum watermark to be able to guarantee progress */
+ watermark = low_wmark_pages(zone) +
+ (PAGE_REPORTING_CAPACITY << PAGE_REPORTING_MIN_ORDER);
+
+ /*
+ * Cancel request if insufficient free memory or if we failed
+ * to allocate page reporting statistics for the zone.
+ */
+ if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
+ return err;
+
+ /* Process each free list starting from lowest order/mt */
+ for (order = PAGE_REPORTING_MIN_ORDER; order < MAX_ORDER; order++) {
+ for (mt = 0; mt < MIGRATE_TYPES; mt++) {
+ /* We do not pull pages from the isolate free list */
+ if (is_migrate_isolate(mt))
+ continue;
+
+ err = page_reporting_cycle(prdev, zone, order, mt,
+ sgl, &offset);
+ if (err)
+ return err;
+ }
+ }
+
+ /* report the leftover pages before going idle */
+ leftover = PAGE_REPORTING_CAPACITY - offset;
+ if (leftover) {
+ sgl = &sgl[offset];
+ err = prdev->report(prdev, sgl, leftover);
+
+ /* flush any remaining pages out from the last report */
+ spin_lock_irq(&zone->lock);
+ page_reporting_drain(prdev, sgl, leftover, !err);
+ spin_unlock_irq(&zone->lock);
+ }
+
+ return err;
+}
+
+static void page_reporting_process(struct work_struct *work)
+{
+ struct delayed_work *d_work = to_delayed_work(work);
+ struct page_reporting_dev_info *prdev =
+ container_of(d_work, struct page_reporting_dev_info, work);
+ int err = 0, state = PAGE_REPORTING_ACTIVE;
+ struct scatterlist *sgl;
+ struct zone *zone;
+
+ /*
+ * Change the state to "Active" so that we can track if there is
+ * anyone requests page reporting after we complete our pass. If
+ * the state is not altered by the end of the pass we will switch
+ * to idle and quit scheduling reporting runs.
+ */
+ atomic_set(&prdev->state, state);
+
+ /* allocate scatterlist to store pages being reported on */
+ sgl = kmalloc_array(PAGE_REPORTING_CAPACITY, sizeof(*sgl), GFP_KERNEL);
+ if (!sgl)
+ goto err_out;
+
+ sg_init_table(sgl, PAGE_REPORTING_CAPACITY);
+
+ for_each_zone(zone) {
+ err = page_reporting_process_zone(prdev, sgl, zone);
+ if (err)
+ break;
+ }
+
+ kfree(sgl);
+err_out:
+ /*
+ * If the state has reverted back to requested then there may be
+ * additional pages to be processed. We will defer for 2s to allow
+ * more pages to accumulate.
+ */
+ state = atomic_cmpxchg(&prdev->state, state, PAGE_REPORTING_IDLE);
+ if (state == PAGE_REPORTING_REQUESTED)
+ schedule_delayed_work(&prdev->work, PAGE_REPORTING_DELAY);
+}
+
+static DEFINE_MUTEX(page_reporting_mutex);
+DEFINE_STATIC_KEY_FALSE(page_reporting_enabled);
+
+int page_reporting_register(struct page_reporting_dev_info *prdev)
+{
+ int err = 0;
+
+ mutex_lock(&page_reporting_mutex);
+
+ /* nothing to do if already in use */
+ if (rcu_access_pointer(pr_dev_info)) {
+ err = -EBUSY;
+ goto err_out;
+ }
+
+ /* initialize state and work structures */
+ atomic_set(&prdev->state, PAGE_REPORTING_IDLE);
+ INIT_DELAYED_WORK(&prdev->work, &page_reporting_process);
+
+ /* Begin initial flush of zones */
+ __page_reporting_request(prdev);
+
+ /* Assign device to allow notifications */
+ rcu_assign_pointer(pr_dev_info, prdev);
+
+ /* enable page reporting notification */
+ if (!static_key_enabled(&page_reporting_enabled)) {
+ static_branch_enable(&page_reporting_enabled);
+ pr_info("Free page reporting enabled\n");
+ }
+err_out:
+ mutex_unlock(&page_reporting_mutex);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(page_reporting_register);
+
+void page_reporting_unregister(struct page_reporting_dev_info *prdev)
+{
+ mutex_lock(&page_reporting_mutex);
+
+ if (rcu_access_pointer(pr_dev_info) == prdev) {
+ /* Disable page reporting notification */
+ RCU_INIT_POINTER(pr_dev_info, NULL);
+ synchronize_rcu();
+
+ /* Flush any existing work, and lock it out */
+ cancel_delayed_work_sync(&prdev->work);
+ }
+
+ mutex_unlock(&page_reporting_mutex);
+}
+EXPORT_SYMBOL_GPL(page_reporting_unregister);