From: Maulik Shah <mkshah@codeaurora.org>
To: Evan Green <evgreen@chromium.org>
Cc: Stephen Boyd <swboyd@chromium.org>,
Matthias Kaehlcke <mka@chromium.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Andy Gross <agross@kernel.org>,
Doug Anderson <dianders@chromium.org>,
Rajendra Nayak <rnayak@codeaurora.org>,
Lina Iyer <ilina@codeaurora.org>,
lsrao@codeaurora.org
Subject: Re: [PATCH v9 2/3] soc: qcom: rpmh: Update dirty flag only when data changes
Date: Mon, 2 Mar 2020 17:08:25 +0530 [thread overview]
Message-ID: <73906d43-cfac-59c4-5e50-51424f0c136f@codeaurora.org> (raw)
In-Reply-To: <CAE=gft5aOtOx6MyuNuv3ebc6ZHmG_W3i0EA3HJjKceYMr7Nx3A@mail.gmail.com>
On 2/29/2020 3:20 AM, Evan Green wrote:
> On Fri, Feb 28, 2020 at 3:38 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>> Currently rpmh ctrlr dirty flag is set for all cases regardless of data
>> is really changed or not. Add changes to update dirty flag when data is
>> changed to newer values.
>>
>> Also move dirty flag updates to happen from within cache_lock and remove
>> unnecessary INIT_LIST_HEAD() call and a default case from switch.
>>
>> Fixes: 600513dfeef3 ("drivers: qcom: rpmh: cache sleep/wake state requests")
>> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
>> Reviewed-by: Srinivas Rao L <lsrao@codeaurora.org>
>> ---
>> drivers/soc/qcom/rpmh.c | 21 +++++++++++++--------
>> 1 file changed, 13 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
>> index eb0ded0..f28afe4 100644
>> --- a/drivers/soc/qcom/rpmh.c
>> +++ b/drivers/soc/qcom/rpmh.c
>> @@ -133,26 +133,30 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
>>
>> req->addr = cmd->addr;
>> req->sleep_val = req->wake_val = UINT_MAX;
>> - INIT_LIST_HEAD(&req->list);
>> list_add_tail(&req->list, &ctrlr->cache);
>>
>> existing:
>> switch (state) {
>> case RPMH_ACTIVE_ONLY_STATE:
>> - if (req->sleep_val != UINT_MAX)
>> + if (req->sleep_val != UINT_MAX) {
>> req->wake_val = cmd->data;
>> + ctrlr->dirty = true;
>> + }
>> break;
>> case RPMH_WAKE_ONLY_STATE:
>> - req->wake_val = cmd->data;
>> + if (req->wake_val != cmd->data) {
>> + req->wake_val = cmd->data;
>> + ctrlr->dirty = true;
>> + }
>> break;
>> case RPMH_SLEEP_STATE:
>> - req->sleep_val = cmd->data;
>> - break;
>> - default:
>> + if (req->sleep_val != cmd->data) {
>> + req->sleep_val = cmd->data;
>> + ctrlr->dirty = true;
>> + }
>> break;
>> }
>>
>> - ctrlr->dirty = true;
>> unlock:
>> spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>>
>> @@ -287,6 +291,7 @@ static void cache_batch(struct rpmh_ctrlr *ctrlr, struct batch_cache_req *req)
>>
>> spin_lock_irqsave(&ctrlr->cache_lock, flags);
>> list_add_tail(&req->list, &ctrlr->batch_cache);
>> + ctrlr->dirty = true;
> Is this fixing a case where we were not previously marking the
> controller dirty but should have?
Well, its not a missing case as such.
Let me explain.
Whenever rpmh_invalidate() (lets call it event a) is called, controller
dirty flag is set.
post invalidating, the aggregator driver always sends new sleep data
(event b) and wake data (event c).
the last cpu going down flushes the cached data and dirty flag is
unset. (event d)
hence setting dirty flag, only once during (event a) and not updating it
during (event b, c) was not any issue/missing case, at least till now.
However with changes to invoke rpmh_flush() whenever data is dirty, it
is required to set this flag for each of these events.
Otherwise as the rpmh_flush() call happened during event b would have
marked as non-dirty data at the end of it,
now when rpmh_flush() call happened during event c, it will not flush
anything as caches are not dirty, which is not the expectation.
> I notice there's a fixes tag, but it
> would be helpful to add something to the commit text indicating that
> you're fixing a missing case where the controller should have been
> marked dirty.
sure i can add details on why we need to update dirty flag everytime
when touching caches.
> With that fixed, you can add my tag:
>
> Reviewed-by: Evan Green <evgreen@chromium.org>
Thanks
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
next prev parent reply other threads:[~2020-03-02 11:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-28 11:38 [PATCH v9 0/3] Invoke rpmh_flush for non OSI targets Maulik Shah
2020-02-28 11:38 ` [PATCH v9 1/3] arm64: dts: qcom: sc7180: Add cpuidle low power states Maulik Shah
2020-02-28 11:38 ` [PATCH v9 2/3] soc: qcom: rpmh: Update dirty flag only when data changes Maulik Shah
2020-02-28 21:50 ` Evan Green
2020-03-02 11:38 ` Maulik Shah [this message]
2020-02-28 11:38 ` [PATCH v9 3/3] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches Maulik Shah
2020-02-28 21:48 ` Evan Green
2020-03-03 5:48 ` Maulik Shah
2020-02-28 23:45 ` Doug Anderson
2020-03-03 5:47 ` Maulik Shah
2020-03-04 0:40 ` Doug Anderson
2020-03-05 9:41 ` Maulik Shah
2020-03-05 22:18 ` Doug Anderson
2020-03-10 9:11 ` Maulik Shah
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=73906d43-cfac-59c4-5e50-51424f0c136f@codeaurora.org \
--to=mkshah@codeaurora.org \
--cc=agross@kernel.org \
--cc=bjorn.andersson@linaro.org \
--cc=dianders@chromium.org \
--cc=evgreen@chromium.org \
--cc=ilina@codeaurora.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lsrao@codeaurora.org \
--cc=mka@chromium.org \
--cc=rnayak@codeaurora.org \
--cc=swboyd@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).