* [PATCH] erofs: avoid unnecessary loops in z_erofs_pcluster_readmore() when read page beyond EOF
@ 2023-07-10 4:25 ` Chunhai Guo
0 siblings, 0 replies; 10+ messages in thread
From: Chunhai Guo @ 2023-07-10 4:25 UTC (permalink / raw)
To: xiang, chao; +Cc: huyue2, jefflexu, linux-erofs, linux-kernel, Chunhai Guo
z_erofs_pcluster_readmore() may take a long time to loop when the page
offset is large enough, which is unnecessary should be prevented.
For example, when the following case is encountered, it will loop 4691368
times, taking about 27 seconds.
- offset = 19217289215
- inode_size = 1442672
Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
---
fs/erofs/zdata.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 5f1890e309c6..d9a0763f4595 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1841,7 +1841,7 @@ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f,
}
cur = map->m_la + map->m_llen - 1;
- while (cur >= end) {
+ while ((cur >= end) && (cur < i_size_read(inode))) {
pgoff_t index = cur >> PAGE_SHIFT;
struct page *page;
--
2.25.1
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH] erofs: avoid unnecessary loops in z_erofs_pcluster_readmore() when read page beyond EOF
2023-07-10 4:25 ` Chunhai Guo
@ 2023-07-10 4:40 ` Gao Xiang
-1 siblings, 0 replies; 10+ messages in thread
From: Gao Xiang @ 2023-07-10 4:40 UTC (permalink / raw)
To: Chunhai Guo, xiang, chao; +Cc: huyue2, linux-erofs, linux-kernel
On 2023/7/10 12:25, Chunhai Guo wrote:
> z_erofs_pcluster_readmore() may take a long time to loop when the page
> offset is large enough, which is unnecessary should be prevented.
> For example, when the following case is encountered, it will loop 4691368
> times, taking about 27 seconds.
> - offset = 19217289215
> - inode_size = 1442672
>
> Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
It looks good to me,
Fixes: 386292919c25 ("erofs: introduce readmore decompression strategy")
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH] erofs: avoid unnecessary loops in z_erofs_pcluster_readmore() when read page beyond EOF
@ 2023-07-10 4:40 ` Gao Xiang
0 siblings, 0 replies; 10+ messages in thread
From: Gao Xiang @ 2023-07-10 4:40 UTC (permalink / raw)
To: Chunhai Guo, xiang, chao; +Cc: huyue2, jefflexu, linux-erofs, linux-kernel
On 2023/7/10 12:25, Chunhai Guo wrote:
> z_erofs_pcluster_readmore() may take a long time to loop when the page
> offset is large enough, which is unnecessary should be prevented.
> For example, when the following case is encountered, it will loop 4691368
> times, taking about 27 seconds.
> - offset = 19217289215
> - inode_size = 1442672
>
> Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
It looks good to me,
Fixes: 386292919c25 ("erofs: introduce readmore decompression strategy")
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] erofs: avoid unnecessary loops in z_erofs_pcluster_readmore() when read page beyond EOF
2023-07-10 4:25 ` Chunhai Guo
@ 2023-07-10 7:48 ` Yue Hu
-1 siblings, 0 replies; 10+ messages in thread
From: Yue Hu @ 2023-07-10 7:48 UTC (permalink / raw)
To: Chunhai Guo; +Cc: linux-erofs, linux-kernel, huyue2
On Mon, 10 Jul 2023 12:25:31 +0800
Chunhai Guo <guochunhai@vivo.com> wrote:
> z_erofs_pcluster_readmore() may take a long time to loop when the page
> offset is large enough, which is unnecessary should be prevented.
> For example, when the following case is encountered, it will loop 4691368
> times, taking about 27 seconds.
> - offset = 19217289215
> - inode_size = 1442672
>
> Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
> ---
> fs/erofs/zdata.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index 5f1890e309c6..d9a0763f4595 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -1841,7 +1841,7 @@ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f,
> }
>
> cur = map->m_la + map->m_llen - 1;
> - while (cur >= end) {
> + while ((cur >= end) && (cur < i_size_read(inode))) {
> pgoff_t index = cur >> PAGE_SHIFT;
> struct page *page;
>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH] erofs: avoid unnecessary loops in z_erofs_pcluster_readmore() when read page beyond EOF
@ 2023-07-10 7:48 ` Yue Hu
0 siblings, 0 replies; 10+ messages in thread
From: Yue Hu @ 2023-07-10 7:48 UTC (permalink / raw)
To: Chunhai Guo; +Cc: xiang, chao, linux-erofs, linux-kernel, huyue2
On Mon, 10 Jul 2023 12:25:31 +0800
Chunhai Guo <guochunhai@vivo.com> wrote:
> z_erofs_pcluster_readmore() may take a long time to loop when the page
> offset is large enough, which is unnecessary should be prevented.
> For example, when the following case is encountered, it will loop 4691368
> times, taking about 27 seconds.
> - offset = 19217289215
> - inode_size = 1442672
>
> Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
> ---
> fs/erofs/zdata.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index 5f1890e309c6..d9a0763f4595 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -1841,7 +1841,7 @@ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f,
> }
>
> cur = map->m_la + map->m_llen - 1;
> - while (cur >= end) {
> + while ((cur >= end) && (cur < i_size_read(inode))) {
> pgoff_t index = cur >> PAGE_SHIFT;
> struct page *page;
>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] erofs: avoid unnecessary loops in z_erofs_pcluster_readmore() when read page beyond EOF
2023-07-10 4:25 ` Chunhai Guo
@ 2023-07-10 10:41 ` Gao Xiang
-1 siblings, 0 replies; 10+ messages in thread
From: Gao Xiang @ 2023-07-10 10:41 UTC (permalink / raw)
To: Chunhai Guo, xiang, chao; +Cc: huyue2, linux-erofs, linux-kernel
On 2023/7/10 12:25, Chunhai Guo wrote:
> z_erofs_pcluster_readmore() may take a long time to loop when the page
> offset is large enough, which is unnecessary should be prevented.
> For example, when the following case is encountered, it will loop 4691368
> times, taking about 27 seconds.
> - offset = 19217289215
> - inode_size = 1442672
>
> Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
I will update the subject manually to:
"erofs: avoid useless loops in z_erofs_pcluster_readmore() when reading beyond EOF"
to avoid overly long subject as well...
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] erofs: avoid unnecessary loops in z_erofs_pcluster_readmore() when read page beyond EOF
@ 2023-07-10 10:41 ` Gao Xiang
0 siblings, 0 replies; 10+ messages in thread
From: Gao Xiang @ 2023-07-10 10:41 UTC (permalink / raw)
To: Chunhai Guo, xiang, chao; +Cc: huyue2, jefflexu, linux-erofs, linux-kernel
On 2023/7/10 12:25, Chunhai Guo wrote:
> z_erofs_pcluster_readmore() may take a long time to loop when the page
> offset is large enough, which is unnecessary should be prevented.
> For example, when the following case is encountered, it will loop 4691368
> times, taking about 27 seconds.
> - offset = 19217289215
> - inode_size = 1442672
>
> Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
I will update the subject manually to:
"erofs: avoid useless loops in z_erofs_pcluster_readmore() when reading beyond EOF"
to avoid overly long subject as well...
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] erofs: avoid unnecessary loops in z_erofs_pcluster_readmore() when read page beyond EOF
2023-07-10 4:25 ` Chunhai Guo
@ 2023-07-11 13:56 ` Chao Yu
-1 siblings, 0 replies; 10+ messages in thread
From: Chao Yu @ 2023-07-11 13:56 UTC (permalink / raw)
To: Chunhai Guo, xiang; +Cc: huyue2, linux-erofs, linux-kernel
On 2023/7/10 12:25, Chunhai Guo wrote:
> z_erofs_pcluster_readmore() may take a long time to loop when the page
> offset is large enough, which is unnecessary should be prevented.
> For example, when the following case is encountered, it will loop 4691368
> times, taking about 27 seconds.
> - offset = 19217289215
> - inode_size = 1442672
>
> Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Thanks,
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] erofs: avoid unnecessary loops in z_erofs_pcluster_readmore() when read page beyond EOF
@ 2023-07-11 13:56 ` Chao Yu
0 siblings, 0 replies; 10+ messages in thread
From: Chao Yu @ 2023-07-11 13:56 UTC (permalink / raw)
To: Chunhai Guo, xiang; +Cc: huyue2, jefflexu, linux-erofs, linux-kernel
On 2023/7/10 12:25, Chunhai Guo wrote:
> z_erofs_pcluster_readmore() may take a long time to loop when the page
> offset is large enough, which is unnecessary should be prevented.
> For example, when the following case is encountered, it will loop 4691368
> times, taking about 27 seconds.
> - offset = 19217289215
> - inode_size = 1442672
>
> Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Thanks,
^ permalink raw reply [flat|nested] 10+ messages in thread