Date: Wed, 08 Sep 2010 11:53:20 +0300 From: Andriy Gapon <avg@freebsd.org> To: Kostik Belousov <kostikbel@gmail.com> Cc: freebsd-fs@freebsd.org, Pawel Jakub Dawidek <pjd@freebsd.org> Subject: Re: zfs very poor performance compared to ufs due to lack of cache? Message-ID: <4C874F00.3050605@freebsd.org> In-Reply-To: <20100908084855.GF2465@deviant.kiev.zoral.com.ua> References: <5DB6E7C798E44D33A05673F4B773405E@multiplay.co.uk> <AANLkTikNhsj5myhQCoPaNytUbpHtox1vg9AZm1N-OcMO@mail.gmail.com> <4C85E91E.1010602@icyb.net.ua> <4C873914.40404@freebsd.org> <20100908084855.GF2465@deviant.kiev.zoral.com.ua>
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on 08/09/2010 11:48 Kostik Belousov said the following:
> On Wed, Sep 08, 2010 at 10:19:48AM +0300, Andriy Gapon wrote:
>> on 07/09/2010 10:26 Andriy Gapon said the following:
>>> Interesting. I briefly looked at the code in mappedread(), zfs_vnops.c, and I
>>> have a VM question.
>>> Shouldn't we mark the corresponding page bits as valid after reading data into
>>> the page?
>>> I specifically speak of the block that starts with the following line:
>>> } else if (m != NULL && uio->uio_segflg == UIO_NOCOPY) {
>>> I am taking mdstart_swap as an example and it does m->valid = VM_PAGE_BITS_ALL.
>>>
>>
>> I've chatted with and conclusion seems to be that vm_page_set_validclean() call
>> should be added at the end of the block.
>>
>> Perhaps, something like this:
>>
>> --- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
>> +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
>> @@ -500,6 +500,7 @@ again:
>> sched_unpin();
>> }
>> VM_OBJECT_LOCK(obj);
>> + vm_page_set_validclean(m, off, bytes);
> Only if error == 0, perhaps ?
Yes, I agree, thanks!
--
Andriy Gapon
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