Input/output control apparatus and method for transfering track data from cache module to channel unit during the staging of the data track from device adapter

• US 5,761,531 A
• Filed: 06/07/1996
• Issued: 06/02/1998
• Est. Priority Date: 06/30/1995
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Takatsu, Kazuma, Ohmura, Hideaki, Fueda, Wasako
• Primary Examiner(s): DINH, DUNG C
• Application Number:
  US08/664,263
• Time in Patent Office: 725 Days
• Field of Search: 395/403, 395/445, 395/464, 395/415, 395/416, 395/420, 395/421.06, 395/438, 395/439, 395/441, 395/825, 395/827, 395/826, 395/840, 395/841, 395/894, 711/113, 711/112, 711/121, 711/130
• US Class Current: 710/21
• CPC Class Codes: G06F 11/1666 where the redundant component is memory or memory area
• CPC Class Codes: G06F 11/20 using active fault-masking, e.g. by switching out faulty elements or by switching in spare elements
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache

Abstract

When an input/output request of a channel adapter causes a mishit on a cache and a staging amount by a device adapter reaches a predetermined amount, the cache is set into a hit status and the channel adapter is reactivated. By receiving a hit response, the reactivated channel adapter executes an input and an output for the cache and the staging of the channel adapter in parallel. A defective/alternating track management table which corresponds to track data stored in a cache memory and has each of addresses of a defective track and an alternating track and flag information showing a link state between both of the defective track and the alternating track is provided for an input/output controller. For a retrieving request in which the defective track address is designated, the defective/alternating track management table is retrieved and the corresponding alternating track address is obtained, thereby judging the presence or absence of a registration of a hash table.

Claims

1. An input/output control apparatus which has a channel adapter module coupled to a channel unit, a device adapter module coupled to a device, and a cache control module for managing a cache memory on the basis of a hash table and asynchronously executes an input/output control between said channel unit and said cache memory by said channel adapter module and an input/output control between said cache memory and said device by said device adapter module via a resource manager module, wherein:

said cache control module has a control unit for controlling in a manner such that in the case where no track data exists in the cache memory for an inquiry from said channel adapter module, a mishit is responded to said channel adapter module and, further, a storage area of the track data is newly allocated to the cache memory and information in said storage area is stored into an information region only for use by said channel adapter module and in the case where no track data exists in the cache memory for an inquiry from said device adapter module, a mishit is responded to said device adapter module and, further, a storage area of the track data is newly allocated to the cache memory and information in said storage area is stored into an information region only for use by said device adapter module;

said channel adapter module has a control unit for controlling in a manner such that when the mishit response is received from said cache control module, a staging is requested to said device adapter module via said resource manager module, the channel unit is disconnected, when a reactivation request from said device adapter module is received during the staging, said channel adapter module is recoupled to the channel unit and inquires of said cache control module, and in the case where a hit response and a response indicative of a state during the staging are obtained, an input/output to/from the channel unit is executed in parallel with the staging of said device adapter module while confirming an amount of staged data with reference to a common control information region of said channel adapter module and said device adapter module; and

said device adapter module has a control unit for controlling in a manner such that when the mishit response is received from said cache control module, said device adapter module requests said device to read track data and to stage the track data into said cache memory, and when an amount of data obtained by said staging reaches a predetermined value, a reactivation is requested to said channel adapter module via said resource manager module.

2. An apparatus according to claim 1, wherein said control unit of said device adapter module notifies an end of the staging to said cache control module, thereby setting contents of said hash table corresponding to the track data which was staged into a hit enable status.

3. An apparatus according to claim 1, wherein said control unit of said channel adapter module notifies an end of the input/output control with said channel unit to said cache control module, thereby setting link information of an LRU control into contents of an LRU table corresponding to the track data which was inputted and outputted.

4. An apparatus according to claim 3, wherein when the link information of the LRU control is set into said hash table, in the case where another track data in a write hit status is swept out, said control unit of said cache control module requests said device adapter module to write said swept-out data into said device via said resource manager module.

5. An apparatus according to claim 1, wherein said channel adapter module, said device adapter module, said cache control module, and said resource manager module are connected to a common memory through a bus, said common memory is divided into a main storage and a cache memory, and the exclusive-use allocation information region for the channel adapter module, the exclusive-use allocation information region for said device adapter module, and the common control information region of said channel adapter module and said device adapter module are allocated to said main storage.

6. An apparatus according to claim 5, wherein said cache memory is constructed by a non-volatile memory and a volatile memory, the track data in which a write hit occurred is stored into said non-volatile memory, and the track data in which a read hit occurred is stored into said volatile memory.

7. An apparatus according to claim 1, wherein a data transfer speed between said device adapter module and said device is sufficiently higher than a data transfer speed between said channel unit and said channel adapter module.

8. An apparatus according to claim 1, wherein said device is a disk array unit.

9. An apparatus according to claim 8, wherein said disk array unit has a plurality of ranks each of which is constructed by disk modules connected to a plurality of ports.

10. An apparatus according to claim 8, wherein said disk array unit is connected by two paths through at least two device adapter modules.

11. An apparatus according to claim 9, wherein said disk array unit is constructed by a control module and a disk array having a plurality of disk modules, and said control module has a cache mechanism.

12. An input/output control method of an input/output control apparatus which has a channel adapter module coupled to a channel unit, a device adapter module coupled to a device, and a cache control module for managing a cache memory on the basis of a hash table and asynchronously executes an input/output control between said channel unit and said cache memory by said channel adapter module and an input/output control between said cache memory and said device by said device adapter module via a resource manager module, wherein:

for an inquiry of a cache status from said channel adapter module based on an input/output request of the channel unit, in the case where no track data exists in the cache memory, said cache control module responds a mishit to said channel adapter module and, further, newly allocates a storage area of the track data into the cache memory and stores information in said storage area into an information region only for use by said channel adapter module;

said channel adapter module which received the mishit response from said cache control module requests a staging to said device adapter module via said resource manager module and disconnects the channel unit;

said device adapter module which received the staging request from said channel adapter module side inquires of said cache control module a cache status;

in the case where no track data exists in the cache memory, said cache control module which received the inquiry from said device adapter module responds a mishit to said device adapter module and, further, newly allocates a storage area of the track data to the cache memory and stores allocation information in said storage area into an allocation information region only for use by said device adapter module;

said device adapter module which received the mishit response from said cache control module requests said device to read the track data and to stage the track data into said cache memory and, when an amount of data obtained by said staging reaches a predetermined value, a reactivation is requested to said channel adapter module via said resource manager module; and

said channel adapter module which received the reactivation request from said device adapter module side is recoupled to said channel unit and inquires of said cache control module, and in the case where a hit response and a response indicative of a state during the staging are obtained, said channel adapter module executes an input/output control with the channel unit and the staging of said device adapter module in parallel while confirming the amount of data which was staged with reference to a common control information region of said channel adapter module and said device adapter module.

13. A method according to claim 12, wherein when the staging from said device adapter module is finished, said cache control module sets contents of the hash table corresponding to the track data which was staged into a hit enable status.

14. A method according to claim 12, wherein when the input/output control between said channel adapter module and said channel unit is finished, said cache control module sets link information of an LRU control into contents of an LRU table corresponding to the track data which was inputted and outputted.

15. A method according to claim 14, wherein when the link information of the LRU control is set into said hash table, in the case where another track data in a write hit status is swept out, said cache control module requests said device adapter module to write said swept-out data into said device via said resource manager module.

16. A method according to claim 12, wherein said device adapter module, said cache control module, and said resource manager module are connected to a common memory through a bus, said common memory is divided into a main storage and a cache memory, and said exclusive-use allocation information region of said channel adapter module, said exclusive-use allocation information region of said device adapter module, said common control information region of said channel adapter module and said device adapter module, and said cache memory are stored in said main storage.

17. A method according to claim 16, wherein said cache memory is constructed by a non-volatile memory and a volatile memory, said non-volatile memory is used to store the track data in which a write hit occurred, and said volatile memory is used to store the track data in which a read hit occurred.

18. A method according to claim 12, wherein a data transfer speed between said device adapter module and said device is sufficiently higher than a data transfer speed between said channel unit and said channel adapter module.

19. A method according to claim 18, wherein said device is a disk array unit.