* [PATCH] btrfs: transaction: Commit transaction more frequently for BPF
@ 2019-08-06 8:22 Qu Wenruo
2019-08-06 14:07 ` David Sterba
2019-08-06 15:23 ` Nikolay Borisov
0 siblings, 2 replies; 4+ messages in thread
From: Qu Wenruo @ 2019-08-06 8:22 UTC (permalink / raw)
To: linux-btrfs
Btrfs has btrfs_end_transaction_throttle() which could try to commit
transaction when needed.
However under most cases btrfs_end_transaction_throttle() won't really
commit transaction, due to the hard timing requirement.
Now introduce a new error injection point, btrfs_need_trans_pressure(),
to allow btrfs_should_end_transaction() to return 1 and
btrfs_end_transaction_throttle() to fallback to
btrfs_commit_transaction().
With such more aggressive transaction commit, we can dig deeper into
cases like snapshot drop.
Now each reference drop of btrfs_drop_snapshot() will lead to a
transaction commit, allowing dm-logwrites to catch more details, other
than one big transaction dropping everything.
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/transaction.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 248d535bb14d..2e758957126e 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -10,6 +10,7 @@
#include <linux/pagemap.h>
#include <linux/blkdev.h>
#include <linux/uuid.h>
+#include <linux/error-injection.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
@@ -781,10 +782,18 @@ void btrfs_throttle(struct btrfs_fs_info *fs_info)
wait_current_trans(fs_info);
}
+static noinline bool btrfs_need_trans_pressure(struct btrfs_trans_handle *trans)
+{
+ return false;
+}
+ALLOW_ERROR_INJECTION(btrfs_need_trans_pressure, TRUE);
+
static int should_end_transaction(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
+ if (btrfs_need_trans_pressure(trans))
+ return 1;
if (btrfs_check_space_for_delayed_refs(fs_info))
return 1;
@@ -845,6 +854,8 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
btrfs_trans_release_chunk_metadata(trans);
+ if (throttle && btrfs_need_trans_pressure(trans))
+ return btrfs_commit_transaction(trans);
if (lock && READ_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
if (throttle)
return btrfs_commit_transaction(trans);
--
2.22.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] btrfs: transaction: Commit transaction more frequently for BPF
2019-08-06 8:22 [PATCH] btrfs: transaction: Commit transaction more frequently for BPF Qu Wenruo
@ 2019-08-06 14:07 ` David Sterba
2019-08-06 15:23 ` Nikolay Borisov
1 sibling, 0 replies; 4+ messages in thread
From: David Sterba @ 2019-08-06 14:07 UTC (permalink / raw)
To: Qu Wenruo; +Cc: linux-btrfs
On Tue, Aug 06, 2019 at 04:22:01PM +0800, Qu Wenruo wrote:
> Btrfs has btrfs_end_transaction_throttle() which could try to commit
> transaction when needed.
>
> However under most cases btrfs_end_transaction_throttle() won't really
> commit transaction, due to the hard timing requirement.
>
> Now introduce a new error injection point, btrfs_need_trans_pressure(),
> to allow btrfs_should_end_transaction() to return 1 and
> btrfs_end_transaction_throttle() to fallback to
> btrfs_commit_transaction().
>
> With such more aggressive transaction commit, we can dig deeper into
> cases like snapshot drop.
> Now each reference drop of btrfs_drop_snapshot() will lead to a
> transaction commit, allowing dm-logwrites to catch more details, other
> than one big transaction dropping everything.
>
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
> fs/btrfs/transaction.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
> index 248d535bb14d..2e758957126e 100644
> --- a/fs/btrfs/transaction.c
> +++ b/fs/btrfs/transaction.c
> @@ -10,6 +10,7 @@
> #include <linux/pagemap.h>
> #include <linux/blkdev.h>
> #include <linux/uuid.h>
> +#include <linux/error-injection.h>
> #include "ctree.h"
> #include "disk-io.h"
> #include "transaction.h"
> @@ -781,10 +782,18 @@ void btrfs_throttle(struct btrfs_fs_info *fs_info)
> wait_current_trans(fs_info);
> }
>
Please put a comment here what's the purpose of the function otherwise
the people who like to delete code will find it and you know what will
happen next.
> +static noinline bool btrfs_need_trans_pressure(struct btrfs_trans_handle *trans)
> +{
> + return false;
> +}
> +ALLOW_ERROR_INJECTION(btrfs_need_trans_pressure, TRUE);
> +
> static int should_end_transaction(struct btrfs_trans_handle *trans)
> {
> struct btrfs_fs_info *fs_info = trans->fs_info;
>
> + if (btrfs_need_trans_pressure(trans))
> + return 1;
> if (btrfs_check_space_for_delayed_refs(fs_info))
> return 1;
>
> @@ -845,6 +854,8 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
>
> btrfs_trans_release_chunk_metadata(trans);
>
> + if (throttle && btrfs_need_trans_pressure(trans))
> + return btrfs_commit_transaction(trans);
> if (lock && READ_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
> if (throttle)
> return btrfs_commit_transaction(trans);
> --
> 2.22.0
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] btrfs: transaction: Commit transaction more frequently for BPF
2019-08-06 8:22 [PATCH] btrfs: transaction: Commit transaction more frequently for BPF Qu Wenruo
2019-08-06 14:07 ` David Sterba
@ 2019-08-06 15:23 ` Nikolay Borisov
2019-08-06 22:47 ` WenRuo Qu
1 sibling, 1 reply; 4+ messages in thread
From: Nikolay Borisov @ 2019-08-06 15:23 UTC (permalink / raw)
To: Qu Wenruo, linux-btrfs
On 6.08.19 г. 11:22 ч., Qu Wenruo wrote:
> Btrfs has btrfs_end_transaction_throttle() which could try to commit
> transaction when needed.
>
> However under most cases btrfs_end_transaction_throttle() won't really
> commit transaction, due to the hard timing requirement.
>
> Now introduce a new error injection point, btrfs_need_trans_pressure(),
> to allow btrfs_should_end_transaction() to return 1 and
> btrfs_end_transaction_throttle() to fallback to
> btrfs_commit_transaction().
>
> With such more aggressive transaction commit, we can dig deeper into
> cases like snapshot drop.
> Now each reference drop of btrfs_drop_snapshot() will lead to a
> transaction commit, allowing dm-logwrites to catch more details, other
> than one big transaction dropping everything.
>
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
> fs/btrfs/transaction.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
> index 248d535bb14d..2e758957126e 100644
> --- a/fs/btrfs/transaction.c
> +++ b/fs/btrfs/transaction.c
> @@ -10,6 +10,7 @@
> #include <linux/pagemap.h>
> #include <linux/blkdev.h>
> #include <linux/uuid.h>
> +#include <linux/error-injection.h>
> #include "ctree.h"
> #include "disk-io.h"
> #include "transaction.h"
> @@ -781,10 +782,18 @@ void btrfs_throttle(struct btrfs_fs_info *fs_info)
> wait_current_trans(fs_info);
> }
>
> +static noinline bool btrfs_need_trans_pressure(struct btrfs_trans_handle *trans)
> +{
> + return false;
> +}
> +ALLOW_ERROR_INJECTION(btrfs_need_trans_pressure, TRUE);
> +
> static int should_end_transaction(struct btrfs_trans_handle *trans)
> {
> struct btrfs_fs_info *fs_info = trans->fs_info;
>
> + if (btrfs_need_trans_pressure(trans))
> + return 1;
> if (btrfs_check_space_for_delayed_refs(fs_info))
> return 1;
>
> @@ -845,6 +854,8 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
>
> btrfs_trans_release_chunk_metadata(trans);
>
> + if (throttle && btrfs_need_trans_pressure(trans))
> + return btrfs_commit_transaction(trans);
I'd rather have this gated behind CONFIG_BTRFS_DEBUG.
> if (lock && READ_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
> if (throttle)
> return btrfs_commit_transaction(trans);
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] btrfs: transaction: Commit transaction more frequently for BPF
2019-08-06 15:23 ` Nikolay Borisov
@ 2019-08-06 22:47 ` WenRuo Qu
0 siblings, 0 replies; 4+ messages in thread
From: WenRuo Qu @ 2019-08-06 22:47 UTC (permalink / raw)
To: Nikolay Borisov, linux-btrfs
On 2019/8/6 下午11:23, Nikolay Borisov wrote:
>
>
> On 6.08.19 г. 11:22 ч., Qu Wenruo wrote:
>> Btrfs has btrfs_end_transaction_throttle() which could try to commit
>> transaction when needed.
>>
>> However under most cases btrfs_end_transaction_throttle() won't really
>> commit transaction, due to the hard timing requirement.
>>
>> Now introduce a new error injection point, btrfs_need_trans_pressure(),
>> to allow btrfs_should_end_transaction() to return 1 and
>> btrfs_end_transaction_throttle() to fallback to
>> btrfs_commit_transaction().
>>
>> With such more aggressive transaction commit, we can dig deeper into
>> cases like snapshot drop.
>> Now each reference drop of btrfs_drop_snapshot() will lead to a
>> transaction commit, allowing dm-logwrites to catch more details, other
>> than one big transaction dropping everything.
>>
>> Signed-off-by: Qu Wenruo <wqu@suse.com>
>> ---
>> fs/btrfs/transaction.c | 11 +++++++++++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
>> index 248d535bb14d..2e758957126e 100644
>> --- a/fs/btrfs/transaction.c
>> +++ b/fs/btrfs/transaction.c
>> @@ -10,6 +10,7 @@
>> #include <linux/pagemap.h>
>> #include <linux/blkdev.h>
>> #include <linux/uuid.h>
>> +#include <linux/error-injection.h>
>> #include "ctree.h"
>> #include "disk-io.h"
>> #include "transaction.h"
>> @@ -781,10 +782,18 @@ void btrfs_throttle(struct btrfs_fs_info *fs_info)
>> wait_current_trans(fs_info);
>> }
>>
>> +static noinline bool btrfs_need_trans_pressure(struct btrfs_trans_handle *trans)
>> +{
>> + return false;
>> +}
>> +ALLOW_ERROR_INJECTION(btrfs_need_trans_pressure, TRUE);
>> +
>> static int should_end_transaction(struct btrfs_trans_handle *trans)
>> {
>> struct btrfs_fs_info *fs_info = trans->fs_info;
>>
>> + if (btrfs_need_trans_pressure(trans))
>> + return 1;
>> if (btrfs_check_space_for_delayed_refs(fs_info))
>> return 1;
>>
>> @@ -845,6 +854,8 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
>>
>> btrfs_trans_release_chunk_metadata(trans);
>>
>> + if (throttle && btrfs_need_trans_pressure(trans))
>> + return btrfs_commit_transaction(trans);
>
> I'd rather have this gated behind CONFIG_BTRFS_DEBUG.
Then we need both CONFIG_BTRFS_DEBUG and CONFIG_BPF_KPROBE_OVERRIDE to
enable this feature.
And for CONFIG_BTRFS_DEBUG not enabled case, that function would not be
used at all (if you also gate the one in should_end_transaction()).
Not sure if extra hassle is really worthy for such a simple debug feature.
Thanks,
Qu
>
>
>> if (lock && READ_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
>> if (throttle)
>> return btrfs_commit_transaction(trans);
>>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-08-06 22:48 UTC | newest]
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2019-08-06 8:22 [PATCH] btrfs: transaction: Commit transaction more frequently for BPF Qu Wenruo
2019-08-06 14:07 ` David Sterba
2019-08-06 15:23 ` Nikolay Borisov
2019-08-06 22:47 ` WenRuo Qu
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