The patch titled
Subject: zram: split memory-tracking and ac-time tracking
has been added to the -mm mm-unstable branch. Its filename is
zram-split-memory-tracking-and-ac-time-tracking.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-split-memory-tracking-and-ac-time-tracking.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Subject: zram: split memory-tracking and ac-time tracking
Date: Wed, 15 Nov 2023 11:42:12 +0900
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.
Link: https://lkml.kernel.org/r/20231115024223.4133148-1-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/blockdev/zram.rst | 2 -
drivers/block/zram/Kconfig | 11 ++++++-
drivers/block/zram/zram_drv.c | 27 ++++++++----------
drivers/block/zram/zram_drv.h | 2 -
4 files changed, 25 insertions(+), 17 deletions(-)
--- a/Documentation/admin-guide/blockdev/zram.rst~zram-split-memory-tracking-and-ac-time-tracking
+++ a/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::
--- a/drivers/block/zram/Kconfig~zram-split-memory-tracking-and-ac-time-tracking
+++ a/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.
--- a/drivers/block/zram/zram_drv.c~zram-split-memory-tracking-and-ac-time-tracking
+++ a/drivers/block/zram/zram_drv.c
@@ -174,6 +174,14 @@ static inline u32 zram_get_priority(stru
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,
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 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
*/
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
@@ -841,12 +850,6 @@ 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)
{
@@ -930,10 +933,6 @@ static void zram_debugfs_unregister(stru
#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
@@ -1254,7 +1253,7 @@ static void zram_free_page(struct zram *
{
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))
--- a/drivers/block/zram/zram_drv.h~zram-split-memory-tracking-and-ac-time-tracking
+++ a/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
};
_
Patches currently in -mm which might be from senozhatsky@xxxxxxxxxxxx are
zram-split-memory-tracking-and-ac-time-tracking.patch
zram-tweak-writeback-config-help.patch
