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Date:   Fri, 04 Jun 2021 09:49:28 +0800
From:   Can Guo <cang@codeaurora.org>
To:     Stanley Chu <stanley.chu@mediatek.com>
Cc:     asutoshd@codeaurora.org, nguyenb@codeaurora.org,
        hongwus@codeaurora.org, linux-scsi@vger.kernel.org,
        kernel-team@android.com, Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Bean Huo <beanhuo@micron.com>,
        Jaegeuk Kim <jaegeuk@kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Kiwoong Kim <kwmad.kim@samsung.com>,
        Satya Tangirala <satyat@google.com>,
        open list <linux-kernel@vger.kernel.org>,
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        <linux-arm-kernel@lists.infradead.org>,
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        <linux-mediatek@lists.infradead.org>
Subject: Re: [PATCH v1 2/3] scsi: ufs: Optimize host lock on transfer requests
 send/compl paths
In-Reply-To: <1622688865.7096.6.camel@mtkswgap22>
References: <1621845419-14194-1-git-send-email-cang@codeaurora.org>
 <1621845419-14194-3-git-send-email-cang@codeaurora.org>
 <1622688865.7096.6.camel@mtkswgap22>
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Hi Stanley,

On 2021-06-03 10:54, Stanley Chu wrote:
> Hi Can,
> 
> On Mon, 2021-05-24 at 01:36 -0700, Can Guo wrote:
>> Current UFS IRQ handler is completely wrapped by host lock, and 
>> because
>> ufshcd_send_command() is also protected by host lock, when IRQ handler
>> fires, not only the CPU running the IRQ handler cannot send new 
>> requests,
>> the rest CPUs can neither. Move the host lock wrapping the IRQ handler 
>> into
>> specific branches, i.e., ufshcd_uic_cmd_compl(), 
>> ufshcd_check_errors(),
>> ufshcd_tmc_handler() and ufshcd_transfer_req_compl(). Meanwhile, to 
>> further
>> reduce occpuation of host lock in ufshcd_transfer_req_compl(), host 
>> lock is
>> no longer required to call __ufshcd_transfer_req_compl(). As per test, 
>> the
>> optimization can bring considerable gain to random read/write 
>> performance.
>> 
>> Cc: Stanley Chu <stanley.chu@mediatek.com>
>> Co-developed-by: Asutosh Das <asutoshd@codeaurora.org>
>> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
>> Signed-off-by: Can Guo <cang@codeaurora.org>
> 
> According to my test, the performance indeed has impressive improvement
> with this series!
> 

Thanks a lot for your time and review. :)

Regards,
Can Guo.

> Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
> 
> 
> 
> 
>>  #endif
>> 
>>  	bool req_abort_skip;
>> -	bool in_use;
>>  };
>> 
>>  /**