This is a note to let you know that I've just added the patch titled
zram: split memory-tracking and ac-time tracking
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
zram-split-memory-tracking-and-ac-time-tracking.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6437f33a1071d6aa2a505dcb4c8e743d856add19
Author: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Date: Wed Nov 15 11:42:12 2023 +0900
zram: split memory-tracking and ac-time tracking
[ Upstream commit a7a0350583ba51d8cde6180bb51d704b89a3b29e ]
ZRAM_MEMORY_TRACKING enables two features:
- per-entry ac-time tracking
- debugfs interface
The latter one is the reason why memory-tracking depends on DEBUG_FS,
while the former one is used far beyond debugging these days. Namely
ac-time is used for fine grained writeback of idle entries (pages).
Move ac-time tracking under its own config option so that it can be
enabled (along with writeback) on systems without DEBUG_FS.
[senozhatsky@xxxxxxxxxxxx: ifdef fixup, per Dmytro]
Link: https://lkml.kernel.org/r/20231117013543.540280-1-senozhatsky@xxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20231115024223.4133148-1-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Dmytro Maluka <dmaluka@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Stable-dep-of: d37da422edb0 ("zram: clear IDLE flag in mark_idle()")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst
index e4551579cb128..ee2b0030d4168 100644
--- a/Documentation/admin-guide/blockdev/zram.rst
+++ b/Documentation/admin-guide/blockdev/zram.rst
@@ -328,7 +328,7 @@ as idle::
From now on, any pages on zram are idle pages. The idle mark
will be removed until someone requests access of the block.
IOW, unless there is access request, those pages are still idle pages.
-Additionally, when CONFIG_ZRAM_MEMORY_TRACKING is enabled pages can be
+Additionally, when CONFIG_ZRAM_TRACK_ENTRY_ACTIME is enabled pages can be
marked as idle based on how long (in seconds) it's been since they were
last accessed::
diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig
index 0386b7da02aa3..af201392ed52c 100644
--- a/drivers/block/zram/Kconfig
+++ b/drivers/block/zram/Kconfig
@@ -69,9 +69,18 @@ config ZRAM_WRITEBACK
See Documentation/admin-guide/blockdev/zram.rst for more information.
+config ZRAM_TRACK_ENTRY_ACTIME
+ bool "Track access time of zram entries"
+ depends on ZRAM
+ help
+ With this feature zram tracks access time of every stored
+ entry (page), which can be used for a more fine grained IDLE
+ pages writeback.
+
config ZRAM_MEMORY_TRACKING
bool "Track zRam block status"
depends on ZRAM && DEBUG_FS
+ select ZRAM_TRACK_ENTRY_ACTIME
help
With this feature, admin can track the state of allocated blocks
of zRAM. Admin could see the information via
@@ -86,4 +95,4 @@ config ZRAM_MULTI_COMP
This will enable multi-compression streams, so that ZRAM can
re-compress pages using a potentially slower but more effective
compression algorithm. Note, that IDLE page recompression
- requires ZRAM_MEMORY_TRACKING.
+ requires ZRAM_TRACK_ENTRY_ACTIME.
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index c29c471b6a182..582df13bfde94 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -174,6 +174,14 @@ static inline u32 zram_get_priority(struct zram *zram, u32 index)
return prio & ZRAM_COMP_PRIORITY_MASK;
}
+static void zram_accessed(struct zram *zram, u32 index)
+{
+ zram_clear_flag(zram, index, ZRAM_IDLE);
+#ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
+ zram->table[index].ac_time = ktime_get_boottime();
+#endif
+}
+
static inline void update_used_max(struct zram *zram,
const unsigned long pages)
{
@@ -293,8 +301,9 @@ static void mark_idle(struct zram *zram, ktime_t cutoff)
zram_slot_lock(zram, index);
if (zram_allocated(zram, index) &&
!zram_test_flag(zram, index, ZRAM_UNDER_WB)) {
-#ifdef CONFIG_ZRAM_MEMORY_TRACKING
- is_idle = !cutoff || ktime_after(cutoff, zram->table[index].ac_time);
+#ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
+ is_idle = !cutoff || ktime_after(cutoff,
+ zram->table[index].ac_time);
#endif
if (is_idle)
zram_set_flag(zram, index, ZRAM_IDLE);
@@ -317,7 +326,7 @@ static ssize_t idle_store(struct device *dev,
*/
u64 age_sec;
- if (IS_ENABLED(CONFIG_ZRAM_MEMORY_TRACKING) && !kstrtoull(buf, 0, &age_sec))
+ if (IS_ENABLED(CONFIG_ZRAM_TRACK_ENTRY_ACTIME) && !kstrtoull(buf, 0, &age_sec))
cutoff_time = ktime_sub(ktime_get_boottime(),
ns_to_ktime(age_sec * NSEC_PER_SEC));
else
@@ -844,12 +853,6 @@ static void zram_debugfs_destroy(void)
debugfs_remove_recursive(zram_debugfs_root);
}
-static void zram_accessed(struct zram *zram, u32 index)
-{
- zram_clear_flag(zram, index, ZRAM_IDLE);
- zram->table[index].ac_time = ktime_get_boottime();
-}
-
static ssize_t read_block_state(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
@@ -933,10 +936,6 @@ static void zram_debugfs_unregister(struct zram *zram)
#else
static void zram_debugfs_create(void) {};
static void zram_debugfs_destroy(void) {};
-static void zram_accessed(struct zram *zram, u32 index)
-{
- zram_clear_flag(zram, index, ZRAM_IDLE);
-};
static void zram_debugfs_register(struct zram *zram) {};
static void zram_debugfs_unregister(struct zram *zram) {};
#endif
@@ -1257,7 +1256,7 @@ static void zram_free_page(struct zram *zram, size_t index)
{
unsigned long handle;
-#ifdef CONFIG_ZRAM_MEMORY_TRACKING
+#ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
zram->table[index].ac_time = 0;
#endif
if (zram_test_flag(zram, index, ZRAM_IDLE))
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index ca7a15bd48456..35e3221446292 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -69,7 +69,7 @@ struct zram_table_entry {
unsigned long element;
};
unsigned long flags;
-#ifdef CONFIG_ZRAM_MEMORY_TRACKING
+#ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
ktime_t ac_time;
#endif
};
