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From: Ilya Dryomov <idryomov@gmail.com>
To: Xiubo Li <xiubli@redhat.com>
Cc: ceph-devel@vger.kernel.org, jlayton@kernel.org,
	vshankar@redhat.com,  mchangir@redhat.com
Subject: Re: [PATCH v2] libceph: increase the max extents check for sparse read
Date: Mon, 6 Nov 2023 13:35:03 +0100	[thread overview]
Message-ID: <CAOi1vP8cD4K7-sjofz+5D4L4GXAgrGD4Z1Ftpk+qtyq8-W-shg@mail.gmail.com> (raw)
In-Reply-To: <b23e8296-ca61-6be5-e07f-f0e184ac3c55@redhat.com>

On Mon, Nov 6, 2023 at 1:20 PM Xiubo Li <xiubli@redhat.com> wrote:
>
>
> On 11/6/23 19:46, Ilya Dryomov wrote:
> > On Mon, Nov 6, 2023 at 2:05 AM <xiubli@redhat.com> wrote:
> >> From: Xiubo Li <xiubli@redhat.com>
> >>
> >> There is no any limit for the extent array size and it's possible
> >> that we will hit 4096 limit just after a lot of random writes to
> >> a file and then read with a large size. In this case the messager
> >> will fail by reseting the connection and keeps resending the inflight
> >> IOs infinitely.
> >>
> >> Just increase the limit to a larger number and then warn it to
> >> let user know that allocating memory could fail with this.
> >>
> >> URL: https://tracker.ceph.com/issues/62081
> >> Signed-off-by: Xiubo Li <xiubli@redhat.com>
> >> ---
> >>
> >> V2:
> >> - Increase the MAX_EXTENTS instead of removing it.
> >> - Do not return an errno when hit the limit.
> >>
> >>
> >>   net/ceph/osd_client.c | 15 +++++++--------
> >>   1 file changed, 7 insertions(+), 8 deletions(-)
> >>
> >> diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
> >> index c03d48bd3aff..050dc39065fb 100644
> >> --- a/net/ceph/osd_client.c
> >> +++ b/net/ceph/osd_client.c
> >> @@ -5850,7 +5850,7 @@ static inline void convert_extent_map(struct ceph_sparse_read *sr)
> >>   }
> >>   #endif
> >>
> >> -#define MAX_EXTENTS 4096
> >> +#define MAX_EXTENTS (16*1024*1024)
> > I don't think this is a sensible limit -- see my other reply.
>
> Ilya,
>
> As I mentioned in that thread, the sparse read could be enabled in
> non-fscrypt case. If so the "64M (CEPH_MSG_MAX_DATA_LEN) / 4K = 16384"
> still won't be enough.

I have just replied in the other thread.  Let's continue this
discussion there ;)

Thanks,

                Ilya

      reply	other threads:[~2023-11-06 12:35 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-06  1:03 [PATCH v2] libceph: increase the max extents check for sparse read xiubli
2023-11-06 11:17 ` Jeff Layton
2023-11-06 11:46 ` Ilya Dryomov
2023-11-06 12:20   ` Xiubo Li
2023-11-06 12:35     ` Ilya Dryomov [this message]

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