* + zram-add-writeback-batch-size-device-attr.patch added to mm-unstable branch
@ 2025-11-18 18:12 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2025-11-18 18:12 UTC (permalink / raw)
To: mm-commits, ywen.chen, richardycc, minchan, bgeffon, senozhatsky,
akpm
The patch titled
Subject: zram: add writeback batch size device attr
has been added to the -mm mm-unstable branch. Its filename is
zram-add-writeback-batch-size-device-attr.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-add-writeback-batch-size-device-attr.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
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*** 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@chromium.org>
Subject: zram: add writeback batch size device attr
Date: Tue, 18 Nov 2025 16:29:56 +0900
Introduce writeback_batch_size device attribute so that the maximum number
of in-flight writeback bio requests can be configured at run-time
per-device. This essentially enables batched bio writeback.
Link: https://lkml.kernel.org/r/20251118073000.1928107-3-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Yuwen Chen <ywen.chen@foxmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/block/zram/zram_drv.c | 48 ++++++++++++++++++++++++++++----
drivers/block/zram/zram_drv.h | 1
2 files changed, 43 insertions(+), 6 deletions(-)
--- a/drivers/block/zram/zram_drv.c~zram-add-writeback-batch-size-device-attr
+++ a/drivers/block/zram/zram_drv.c
@@ -588,6 +588,42 @@ static ssize_t writeback_limit_show(stru
return sysfs_emit(buf, "%llu\n", val);
}
+static ssize_t writeback_batch_size_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct zram *zram = dev_to_zram(dev);
+ u32 val;
+ ssize_t ret = -EINVAL;
+
+ if (kstrtouint(buf, 10, &val))
+ return ret;
+
+ if (!val)
+ val = 1;
+
+ down_read(&zram->init_lock);
+ zram->wb_batch_size = val;
+ up_read(&zram->init_lock);
+ ret = len;
+
+ return ret;
+}
+
+static ssize_t writeback_batch_size_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ u32 val;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ val = zram->wb_batch_size;
+ up_read(&zram->init_lock);
+
+ return sysfs_emit(buf, "%u\n", val);
+}
+
static void reset_bdev(struct zram *zram)
{
if (!zram->backing_dev)
@@ -775,10 +811,7 @@ static void release_wb_ctl(struct zram_w
kfree(wb_ctl);
}
-/* XXX: should be a per-device sysfs attr */
-#define ZRAM_WB_REQ_CNT 32
-
-static struct zram_wb_ctl *init_wb_ctl(void)
+static struct zram_wb_ctl *init_wb_ctl(struct zram *zram)
{
struct zram_wb_ctl *wb_ctl;
int i;
@@ -792,7 +825,7 @@ static struct zram_wb_ctl *init_wb_ctl(v
atomic_set(&wb_ctl->num_inflight, 0);
init_completion(&wb_ctl->done);
- for (i = 0; i < ZRAM_WB_REQ_CNT; i++) {
+ for (i = 0; i < zram->wb_batch_size; i++) {
struct zram_wb_req *req;
/*
@@ -1183,7 +1216,7 @@ static ssize_t writeback_store(struct de
goto release_init_lock;
}
- wb_ctl = init_wb_ctl();
+ wb_ctl = init_wb_ctl(zram);
if (!wb_ctl) {
ret = -ENOMEM;
goto release_init_lock;
@@ -2826,6 +2859,7 @@ static DEVICE_ATTR_RW(backing_dev);
static DEVICE_ATTR_WO(writeback);
static DEVICE_ATTR_RW(writeback_limit);
static DEVICE_ATTR_RW(writeback_limit_enable);
+static DEVICE_ATTR_RW(writeback_batch_size);
#endif
#ifdef CONFIG_ZRAM_MULTI_COMP
static DEVICE_ATTR_RW(recomp_algorithm);
@@ -2847,6 +2881,7 @@ static struct attribute *zram_disk_attrs
&dev_attr_writeback.attr,
&dev_attr_writeback_limit.attr,
&dev_attr_writeback_limit_enable.attr,
+ &dev_attr_writeback_batch_size.attr,
#endif
&dev_attr_io_stat.attr,
&dev_attr_mm_stat.attr,
@@ -2908,6 +2943,7 @@ static int zram_add(void)
init_rwsem(&zram->init_lock);
#ifdef CONFIG_ZRAM_WRITEBACK
+ zram->wb_batch_size = 32;
spin_lock_init(&zram->wb_limit_lock);
#endif
--- a/drivers/block/zram/zram_drv.h~zram-add-writeback-batch-size-device-attr
+++ a/drivers/block/zram/zram_drv.h
@@ -129,6 +129,7 @@ struct zram {
struct file *backing_dev;
spinlock_t wb_limit_lock;
bool wb_limit_enable;
+ u32 wb_batch_size;
u64 bd_wb_limit;
struct block_device *bdev;
unsigned long *bitmap;
_
Patches currently in -mm which might be from senozhatsky@chromium.org are
zram-add-writeback-batch-size-device-attr.patch
zram-take-write-lock-in-wb-limit-store-handlers.patch
zram-drop-wb_limit_lock.patch
zram-rework-bdev-block-allocation.patch
zram-read-slot-block-idx-under-slot-lock.patch
^ permalink raw reply [flat|nested] 2+ messages in thread* + zram-add-writeback-batch-size-device-attr.patch added to mm-unstable branch
@ 2025-11-17 18:44 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2025-11-17 18:44 UTC (permalink / raw)
To: mm-commits, ywen.chen, richardycc, minchan, bgeffon, senozhatsky,
akpm
The patch titled
Subject: zram: add writeback batch size device attr
has been added to the -mm mm-unstable branch. Its filename is
zram-add-writeback-batch-size-device-attr.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-add-writeback-batch-size-device-attr.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@chromium.org>
Subject: zram: add writeback batch size device attr
Date: Sat, 15 Nov 2025 11:34:45 +0900
Introduce writeback_batch_size device attribute so that the maximum number
of in-flight writeback bio requests can be configured at run-time
per-device. This essentially enables batched bio writeback.
Link: https://lkml.kernel.org/r/20251115023447.495417-3-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Yuwen Chen <ywen.chen@foxmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/block/zram/zram_drv.c | 48 ++++++++++++++++++++++++++++----
drivers/block/zram/zram_drv.h | 1
2 files changed, 43 insertions(+), 6 deletions(-)
--- a/drivers/block/zram/zram_drv.c~zram-add-writeback-batch-size-device-attr
+++ a/drivers/block/zram/zram_drv.c
@@ -588,6 +588,42 @@ static ssize_t writeback_limit_show(stru
return sysfs_emit(buf, "%llu\n", val);
}
+static ssize_t writeback_batch_size_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct zram *zram = dev_to_zram(dev);
+ u32 val;
+ ssize_t ret = -EINVAL;
+
+ if (kstrtouint(buf, 10, &val))
+ return ret;
+
+ if (!val)
+ val = 1;
+
+ down_read(&zram->init_lock);
+ zram->wb_batch_size = val;
+ up_read(&zram->init_lock);
+ ret = len;
+
+ return ret;
+}
+
+static ssize_t writeback_batch_size_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ u32 val;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ val = zram->wb_batch_size;
+ up_read(&zram->init_lock);
+
+ return sysfs_emit(buf, "%u\n", val);
+}
+
static void reset_bdev(struct zram *zram)
{
if (!zram->backing_dev)
@@ -775,10 +811,7 @@ static void release_wb_ctl(struct zram_w
kfree(wb_ctl);
}
-/* XXX: should be a per-device sysfs attr */
-#define ZRAM_WB_REQ_CNT 32
-
-static struct zram_wb_ctl *init_wb_ctl(void)
+static struct zram_wb_ctl *init_wb_ctl(struct zram *zram)
{
struct zram_wb_ctl *wb_ctl;
int i;
@@ -792,7 +825,7 @@ static struct zram_wb_ctl *init_wb_ctl(v
atomic_set(&wb_ctl->num_inflight, 0);
init_completion(&wb_ctl->done);
- for (i = 0; i < ZRAM_WB_REQ_CNT; i++) {
+ for (i = 0; i < zram->wb_batch_size; i++) {
struct zram_wb_req *req;
/*
@@ -1180,7 +1213,7 @@ static ssize_t writeback_store(struct de
goto release_init_lock;
}
- wb_ctl = init_wb_ctl();
+ wb_ctl = init_wb_ctl(zram);
if (!wb_ctl) {
ret = -ENOMEM;
goto release_init_lock;
@@ -2821,6 +2854,7 @@ static DEVICE_ATTR_RW(backing_dev);
static DEVICE_ATTR_WO(writeback);
static DEVICE_ATTR_RW(writeback_limit);
static DEVICE_ATTR_RW(writeback_limit_enable);
+static DEVICE_ATTR_RW(writeback_batch_size);
#endif
#ifdef CONFIG_ZRAM_MULTI_COMP
static DEVICE_ATTR_RW(recomp_algorithm);
@@ -2842,6 +2876,7 @@ static struct attribute *zram_disk_attrs
&dev_attr_writeback.attr,
&dev_attr_writeback_limit.attr,
&dev_attr_writeback_limit_enable.attr,
+ &dev_attr_writeback_batch_size.attr,
#endif
&dev_attr_io_stat.attr,
&dev_attr_mm_stat.attr,
@@ -2903,6 +2938,7 @@ static int zram_add(void)
init_rwsem(&zram->init_lock);
#ifdef CONFIG_ZRAM_WRITEBACK
+ zram->wb_batch_size = 32;
spin_lock_init(&zram->wb_limit_lock);
#endif
--- a/drivers/block/zram/zram_drv.h~zram-add-writeback-batch-size-device-attr
+++ a/drivers/block/zram/zram_drv.h
@@ -129,6 +129,7 @@ struct zram {
struct file *backing_dev;
spinlock_t wb_limit_lock;
bool wb_limit_enable;
+ u32 wb_batch_size;
u64 bd_wb_limit;
struct block_device *bdev;
unsigned long *bitmap;
_
Patches currently in -mm which might be from senozhatsky@chromium.org are
zram-add-writeback-batch-size-device-attr.patch
zram-take-write-lock-in-wb-limit-store-handlers.patch
zram-drop-wb_limit_lock.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
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