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authorKassey Li <quic_yingangl@quicinc.com>2022-08-18 05:24:25 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-09-12 06:25:59 +0300
commit8f0efa81dfbc6abf86bf410549e61a2636753c86 (patch)
tree414635559a44137f109ca936ebb00c70c4b30ac5 /mm/page_owner.c
parent72c33ef4c02e32e2884e7688ec878a486913fe9c (diff)
downloadlinux-8f0efa81dfbc6abf86bf410549e61a2636753c86.tar.xz
mm/page_owner.c: add llseek for page_owner
It is too slow to dump all the pages, in some usage we just want to dump a given start pfn, for example: a CMA range or a single page. To speed up and save time, this change allows specifying of a start pfn by adding llseek for page_owner. Link: https://lkml.kernel.org/r/20220818022425.31056-1-quic_yingangl@quicinc.com Signed-off-by: Kassey Li <quic_yingangl@quicinc.com> Suggested-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/page_owner.c')
-rw-r--r--mm/page_owner.c24
1 files changed, 21 insertions, 3 deletions
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 72839a606e22..90023f938c19 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -516,8 +516,10 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
return -EINVAL;
page = NULL;
- pfn = min_low_pfn + *ppos;
-
+ if (*ppos == 0)
+ pfn = min_low_pfn;
+ else
+ pfn = *ppos;
/* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
pfn++;
@@ -588,7 +590,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
goto ext_put_continue;
/* Record the next PFN to read in the file offset */
- *ppos = (pfn - min_low_pfn) + 1;
+ *ppos = pfn + 1;
page_owner_tmp = *page_owner;
page_ext_put(page_ext);
@@ -601,6 +603,21 @@ ext_put_continue:
return 0;
}
+static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig)
+{
+ switch (orig) {
+ case SEEK_SET:
+ file->f_pos = offset;
+ break;
+ case SEEK_CUR:
+ file->f_pos += offset;
+ break;
+ default:
+ return -EINVAL;
+ }
+ return file->f_pos;
+}
+
static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
{
unsigned long pfn = zone->zone_start_pfn;
@@ -693,6 +710,7 @@ static void init_early_allocated_pages(void)
static const struct file_operations proc_page_owner_operations = {
.read = read_page_owner,
+ .llseek = lseek_page_owner,
};
static int __init pageowner_init(void)