Re: [PATCH v4 2/4] mm/page_reporting: Export reporting order as module parameter
From: Alexander Duyck <hidden>
Date: 2021-06-25 01:14:50
Also in:
lkml
On Thu, Jun 24, 2021 at 4:46 PM Gavin Shan [off-list ref] wrote:
The macro PAGE_REPORTING_MIN_ORDER is defined as the page reporting threshold. It can't be adjusted at runtime. This introduces a variable (@page_reporting_order) to replace the marcro (PAGE_REPORTING_MIN_ORDER). MAX_ORDER is assigned to it initially, meaning the page reporting is disabled. It will be specified by driver if valid one is provided. Otherwise, it will fall back to @pageblock_order. It's also exported so that the page reporting order can be adjusted at runtime. Suggested-by: David Hildenbrand <redacted> Signed-off-by: Gavin Shan <redacted> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
So this patch looks like it is technically broken. We need a line in page_reporting_register that will overwrite the value with pageblock_order if it is less than page_reporting_order.
quoted hunk ↗ jump to hunk
--- Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ mm/page_reporting.c | 9 +++++++-- mm/page_reporting.h | 5 ++--- 3 files changed, 15 insertions(+), 5 deletions(-)diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index cb89dbdedc46..566c4b9af3cd 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt@@ -3566,6 +3566,12 @@ off: turn off poisoning (default) on: turn on poisoning + page_reporting.page_reporting_order= + [KNL] Minimal page reporting order + Format: <integer> + Adjust the minimal page reporting order. The page + reporting is disabled when it exceeds (MAX_ORDER-1). + panic= [KNL] Kernel behaviour on panic: delay <timeout> timeout > 0: seconds before rebooting timeout = 0: wait foreverdiff --git a/mm/page_reporting.c b/mm/page_reporting.c index df9c5054e1b4..34bf4d26c2c4 100644 --- a/mm/page_reporting.c +++ b/mm/page_reporting.c@@ -4,12 +4,17 @@ #include <linux/page_reporting.h> #include <linux/gfp.h> #include <linux/export.h> +#include <linux/module.h> #include <linux/delay.h> #include <linux/scatterlist.h> #include "page_reporting.h" #include "internal.h" +unsigned int page_reporting_order = MAX_ORDER; +module_param(page_reporting_order, uint, 0644); +MODULE_PARM_DESC(page_reporting_order, "Set page reporting order"); + #define PAGE_REPORTING_DELAY (2 * HZ) static struct page_reporting_dev_info __rcu *pr_dev_info __read_mostly;@@ -229,7 +234,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev, /* Generate minimum watermark to be able to guarantee progress */ watermark = low_wmark_pages(zone) + - (PAGE_REPORTING_CAPACITY << PAGE_REPORTING_MIN_ORDER); + (PAGE_REPORTING_CAPACITY << page_reporting_order); /* * Cancel request if insufficient free memory or if we failed@@ -239,7 +244,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev, return err; /* Process each free list starting from lowest order/mt */ - for (order = PAGE_REPORTING_MIN_ORDER; order < MAX_ORDER; order++) { + for (order = page_reporting_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))diff --git a/mm/page_reporting.h b/mm/page_reporting.h index 2c385dd4ddbd..c51dbc228b94 100644 --- a/mm/page_reporting.h +++ b/mm/page_reporting.h@@ -10,10 +10,9 @@ #include <linux/pgtable.h> #include <linux/scatterlist.h> -#define PAGE_REPORTING_MIN_ORDER pageblock_order - #ifdef CONFIG_PAGE_REPORTING DECLARE_STATIC_KEY_FALSE(page_reporting_enabled); +extern unsigned int page_reporting_order; void __page_reporting_notify(void); static inline bool page_reported(struct page *page)@@ -38,7 +37,7 @@ static inline void page_reporting_notify_free(unsigned int order) return; /* Determine if we have crossed reporting threshold */ - if (order < PAGE_REPORTING_MIN_ORDER) + if (order < page_reporting_order) return; /* This will add a few cycles, but should be called infrequently */ --2.23.0