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- Time namespace support: If a container migrates from one host to another then it expects that clocks based on MONOTONIC and BOOTTIME are not subject to disruption. Due to different boot time and non-suspended runtime these clocks can differ significantly on two hosts, in the worst case time goes backwards which is a violation of the POSIX requirements. The time namespace addresses this problem. It allows to set offsets for clock MONOTONIC and BOOTTIME once after creation and before tasks are associated with the namespace. These offsets are taken into account by timers and timekeeping including the VDSO. Offsets for wall clock based clocks (REALTIME/TAI) are not provided by this mechanism. While in theory possible, the overhead and code complexity would be immense and not justified by the esoteric potential use cases which were discussed at Plumbers '18. The overhead for tasks in the root namespace (host time offsets = 0) is in the noise and great effort was made to ensure that especially in the VDSO. If time namespace is disabled in the kernel configuration the code is compiled out. Kudos to Andrei Vagin and Dmitry Sofanov who implemented this feature and kept on for more than a year addressing review comments, finding better solutions. A pleasant experience. - Overhaul of the alarmtimer device dependency handling to ensure that the init/suspend/resume ordering is correct. - A new clocksource/event driver for Microchip PIT64 - Suspend/resume support for the Hyper-V clocksource - The usual pile of fixes, updates and improvements mostly in the driver code. -----BEGIN PGP SIGNATURE----- iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAl4vbTcTHHRnbHhAbGlu dXRyb25peC5kZQAKCRCmGPVMDXSYoXT2D/96iJ3G9Snn2khEQP3XS2rYmtDGw7NO m1n96falwWeGe6zreU80R2Jge5nLxQtNhRoMPLLee1GpHwRC6lvqEqgdZ4LMBrD2 JqV7Gzg8Urmdh+hpDsyTCpeEWEzoMKxiFOX8PxwctqUhM4szEe5iQg2YQsg85Jw2 vG6M93N2xwDILh4rhEMbKjo+5ZmYn7c1RQvpGOSmpKOj940W/N7H2HBsFhdaJ1Kw FW5pFv1211PaU5RV2YNb2dMeeMTT1N3e2VN4Dkadoxp47pb+725gNHEBEjmV9poG Lp4IhzGAPnj8zVD88icQZSTaK3gUHMClxprJ0Pf84WEtiH7SeGu8BPYyu77+oNDe yzcctDJNyCWXkzmaP/fe/HLc0TStbvNAJ5Tagp4BC75gzebeb4/n8RtRT0fKeDYL pxpDPKDAPU7p1JSjxiWAtshqjBycWNY3Z49bA7/VhKBhnv8BDyBPGlYd7/4xrbGr RK7DQNXJwaJaiNJ7p5PiaFxGzNyB0B9sThD/slSlEInIKb4h9YzWr0TV+NB62VnB sDcN+tpLbRPz5/5cHGGfxR0+zKWpfyai8pzbmmaXEaKssjRYwyvcac5EZdgbWpbK k7CqAjoWLA2P+tGeePNJOf5JYK6Vmdyh4clmuwM0zOiRJ9NlWUyMf3z7QYILs4RO UAI+6opYlZEPAw== =x3qT -----END PGP SIGNATURE----- Merge tag 'timers-core-2020-01-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "The timekeeping and timers departement provides: - Time namespace support: If a container migrates from one host to another then it expects that clocks based on MONOTONIC and BOOTTIME are not subject to disruption. Due to different boot time and non-suspended runtime these clocks can differ significantly on two hosts, in the worst case time goes backwards which is a violation of the POSIX requirements. The time namespace addresses this problem. It allows to set offsets for clock MONOTONIC and BOOTTIME once after creation and before tasks are associated with the namespace. These offsets are taken into account by timers and timekeeping including the VDSO. Offsets for wall clock based clocks (REALTIME/TAI) are not provided by this mechanism. While in theory possible, the overhead and code complexity would be immense and not justified by the esoteric potential use cases which were discussed at Plumbers '18. The overhead for tasks in the root namespace (ie where host time offsets = 0) is in the noise and great effort was made to ensure that especially in the VDSO. If time namespace is disabled in the kernel configuration the code is compiled out. Kudos to Andrei Vagin and Dmitry Sofanov who implemented this feature and kept on for more than a year addressing review comments, finding better solutions. A pleasant experience. - Overhaul of the alarmtimer device dependency handling to ensure that the init/suspend/resume ordering is correct. - A new clocksource/event driver for Microchip PIT64 - Suspend/resume support for the Hyper-V clocksource - The usual pile of fixes, updates and improvements mostly in the driver code" * tag 'timers-core-2020-01-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits) alarmtimer: Make alarmtimer_get_rtcdev() a stub when CONFIG_RTC_CLASS=n alarmtimer: Use wakeup source from alarmtimer platform device alarmtimer: Make alarmtimer platform device child of RTC device alarmtimer: Update alarmtimer_get_rtcdev() docs to reflect reality hrtimer: Add missing sparse annotation for __run_timer() lib/vdso: Only read hrtimer_res when needed in __cvdso_clock_getres() MIPS: vdso: Define BUILD_VDSO32 when building a 32bit kernel clocksource/drivers/hyper-v: Set TSC clocksource as default w/ InvariantTSC clocksource/drivers/hyper-v: Untangle stimers and timesync from clocksources clocksource/drivers/timer-microchip-pit64b: Fix sparse warning clocksource/drivers/exynos_mct: Rename Exynos to lowercase clocksource/drivers/timer-ti-dm: Fix uninitialized pointer access clocksource/drivers/timer-ti-dm: Switch to platform_get_irq clocksource/drivers/timer-ti-dm: Convert to devm_platform_ioremap_resource clocksource/drivers/em_sti: Fix variable declaration in em_sti_probe clocksource/drivers/em_sti: Convert to devm_platform_ioremap_resource clocksource/drivers/bcm2835_timer: Fix memory leak of timer clocksource/drivers/cadence-ttc: Use ttc driver as platform driver clocksource/drivers/timer-microchip-pit64b: Add Microchip PIT64B support clocksource/drivers/hyper-v: Reserve PAGE_SIZE space for tsc page ... |
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bindings | ||
booting-without-of.txt | ||
changesets.txt | ||
dynamic-resolution-notes.txt | ||
of_unittest.txt | ||
overlay-notes.txt | ||
usage-model.txt | ||
writing-schema.rst |