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Wed, 11 Jun 2025 07:30:27 -0700 (PDT) Date: Wed, 11 Jun 2025 10:30:24 -0400 From: Yury Norov To: I Hsin Cheng Cc: jstultz@google.com, tglx@linutronix.de, sboyd@kernel.org, linux-kernel@vger.kernel.org, yurynorov@gmail.com, skhan@linuxfoundation.org, linux-kernel-mentees@lists.linux.dev, jserv@ccns.ncku.edu.tw Subject: Re: [PATCH v3] clocksource: Replace loop within clocks_calc_mult_shift() with find_last_bit() for calculation of "sftacc" Message-ID: References: <20250611073608.2049793-1-richard120310@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel-mentees@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Jun 11, 2025 at 10:26:39PM +0800, I Hsin Cheng wrote: > line > In-Reply-To: > Status: O > Content-Length: 5191 > Lines: 144 > > On Wed, Jun 11, 2025 at 07:50:04AM -0400, Yury Norov wrote: > > On Wed, Jun 11, 2025 at 03:36:08PM +0800, I Hsin Cheng wrote: > Hi Yury, > > Thanks for your suggestions ! > > > 1. sftacc is known to be 32. Comparing against 0 is useless. > > 2. Just use __fls(): > > if (tmp) > > sftacc -=__fls(tmp) + 1; > > > > No problem, I'll fix them up in the next version. > Just wondering the reason to use __fls() directly, is it because we're > sure that the value of "tmp" will definitely fall into > small_const_nbits() case in find_last_bit() ? That's because tmp is not a bitmap. It's u64.