Off-line affinity-aware parallel zeroing of memory in non-uniform memory access (NUMA) servers

Patent metadata

Field	Value
Publication number	US-9891861-B2
Application number	US-201514883402-A
Country	US
Kind code	B2
Filing date	Oct 14, 2015
Priority date	Jun 25, 2015
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A method for zeroing memory in computing systems where access to memory is non-uniform includes receiving, via a system call, a request to delete a memory region. The method also includes forwarding the request to an intermediate software thread, and using the intermediate software thread to perform the request as a background process. The method further includes, upon receiving a message from the intermediate software thread, returning to a system caller, while performing the request, via the intermediate software thread, continues in the background.

First claim

What is claimed is:

1. A method for zeroing pages of memory in a computing system where access to memory is non-uniform, the method comprising:
receiving, via a system call, a request to delete a memory region;
forwarding the request to an intermediate software thread;
using the intermediate software thread to perform the request as a background process;
upon receiving from the intermediate software thread an indication that a count of an amount of memory pending free has been updated, returning to a system caller, while performing the request, via the intermediate software thread, continues in the background;
receiving, from a process, a request for a page of memory, wherein a size of the requested page is above a predetermined threshold;
determining that an amount of available memory is lower than the size of the requested page; and
transmitting an indication of the amount of memory pending free to the process, wherein the process determines whether to wait for the request to be granted, based at least in part, on the indicated amount of memory pending free.

2. The method of claim 1 , wherein using the intermediate software thread to perform the request comprises:
sorting one or more pages of the memory region according to each associated affinity domain of each page, wherein each affinity domain comprises a cluster of processors and memory local to the cluster of processors;
sending requests to zero the sorted one or more pages to one or more additional software threads that are attached to the respective affinity domain; and
receiving, from each of the one or more additional software threads, notifications that the requests to zero the sorted one or more pages have been processed.

3. The method of claim 1 , further comprising executing another process while pages of the memory region are zeroed in the background.

4. The method of claim 2 , wherein the one or more additional software threads zero the sorted one or more pages in parallel.

5. A system, comprising:
a processor; and
a memory containing a program which, when executed on the processor, performs an operation for zeroing pages of memory in a computing system where access to memory is non-uniform, the operation comprising:
receiving, via a system call, a request to delete a memory region;
forwarding the request to an intermediate software thread;
using the intermediate software thread to perform the request as a background process;
upon receiving from the intermediate software thread an indication that a count of an amount of memory pending free has been updated, returning to a system caller, while performing the request, via the intermediate software thread, continues in the background;
receiving, from a process, a request for a page of memory, wherein a size of the requested page is above a predetermined threshold;
determining that an amount of available memory is lower than the size of the requested page; and
transmitting an indication of the amount of memory pending free to the process, wherein the process determines whether to wait for the request to be granted, based at least in part, on the indicated amount of memory pending free.

6. The system of claim 5 , wherein using the intermediate software thread to perform the request comprises:
sorting one or more pages of the memory region according to each associated affinity domain of each page, wherein each affinity domain comprises a cluster of processors and memory local to the cluster of processors;
sending requests to zero the sorted one or more pages to one or more additional software threads that are attached to the respective affinity domain; and
receiving, from each of the one or more additional software threads, notifications that the requests to zero the sorted one or more pages have been processed.

7. The system of claim 5 , wherein the operation further comprises executing another process while pages of the memory region are zeroed in the background.

8. The system of claim 6 , wherein the one or more additional software threads zero the sorted one or more pages in parallel.

9. A non-transitory computer-readable storage medium storing instructions, which, when executed on a processor, perform an operation for zeroing pages of memory in a computing system where access to memory is non-uniform, the operation comprising:
receiving, via a system call, a request to delete a memory region;
forwarding the request to an intermediate software thread;
using the intermediate software thread to perform the request as a background process;
upon receiving from the intermediate software thread an indication that a count of an amount of memory pending free has been updated, returning to a system caller, while performing the request, via the intermediate software thread, continues in the background;
receiving, from a process, a request for a page of memory, wherein a size of the requested page is above a predetermined threshold;
determining that an amount of available memory is lower than the size of the requested page; and
transmitting an indication of the amount of memory pending free to the process, wherein the process determines whether to wait for the request to be granted, based at least in part, on the indicated amount of memory pending free.

10. The non-transitory computer-readable storage medium of claim 9 , wherein using the intermediate software thread to perform the request comprises:
sorting one or more pages of the memory region according to each associated affinity domain of each page, wherein each affinity domain comprises a cluster of processors and memory local to the cluster of processors;
sending requests to zero the sorted one or more pages to one or more additional software threads that are attached to the respective affinity domain; and
receiving, from each of the one or more additional software threads, notifications that the requests to zero the sorted one or more pages have been processed.

11. The non-transitory computer-readable storage medium of claim 9 , wherein the operation further comprises executing another process while pages of the memory region are zeroed in the background.

12. The non-transitory computer-readable storage medium of claim 10 , wherein the one or more additional software threads zero the sorted one or more pages in parallel.

Assignees

• IBM

Inventors

• Hegde Nakhil
• Mealey Bruce
• Rogers Mark D

Classifications

• G06F12/023

  Free address space management · CPC title

• G06F12/1009 Primary

  using page tables, e.g. page table structures · CPC title

• G06F2009/45583

  Memory management, e.g. access or allocation · CPC title

• G06F12/0223

  User address space allocation, e.g. contiguous or non contiguous base addressing · CPC title

• G06F9/5016

  the resource being the memory · CPC title