It looks like tboot_wait_for_aps(...) is not called in atomic context . mdelay(1) delays exactly 1msecs, I understand udelay(...) may not be appropriate, as it is used for delay around 20usecs. In terms of reducing busy wait, how can we determine the range in usleep_range(...) is 1000 to 2000, not from 20 to 1000?
Thanks, -ning -----Original Message----- From: Jia-Ju Bai [mailto:baijiaju1...@gmail.com] Sent: Wednesday, January 24, 2018 5:38 AM To: Thomas Gleixner <t...@linutronix.de> Cc: Sun, Ning <ning....@intel.com>; mi...@redhat.com; h...@zytor.com; x...@kernel.org; tboot-devel@lists.sourceforge.net; linux-ker...@vger.kernel.org Subject: Re: [PATCH] kernel: x86: tboot: Replace mdelay with usleep_range in tboot_wait_for_aps On 2018/1/24 19:47, Thomas Gleixner wrote: > On Wed, 24 Jan 2018, Jia-Ju Bai wrote: > >> The function tboot_wait_for_aps is not called in atomic context. >> Thus mdelay can be replaced with usleep_range, to reduce busy wait. > And how did you establish that it's not called in atomic context? > > Thanks, > > tglx It is reported by a static analysis tool written by myself. This tool finds that mdelay in tboot_wait_for_aps is not called by holding a spinlock or in an interrupt handler, thus mdelay can be replaced. Thanks, Jia-Ju Bai ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ tboot-devel mailing list tboot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/tboot-devel
