| Summary: | [RFE] page_cgroup: Reduce allocation overhead for page_cgroup array for CONFIG_SPARSEMEM | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | J.H.M. Dassen (Ray) <rdassen> |
| Component: | kernel | Assignee: | Red Hat Kernel Manager <kernel-mgr> |
| Status: | CLOSED DUPLICATE | QA Contact: | Red Hat Kernel QE team <kernel-qe> |
| Severity: | low | Docs Contact: | |
| Priority: | medium | ||
| Version: | 6.1 | CC: | james.leddy, rbinkhor |
| Target Milestone: | rc | Keywords: | FutureFeature, Triaged |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Enhancement | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2011-04-18 15:58:41 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
*** This bug has been marked as a duplicate of bug 692490 *** |
What is the nature and description of the request? They want to decrease the overhead of cgroups. Today, the kernel uses a lot of 2MB slab objects (8 objects per 1GB of RAM on x86_64 with SPARSEMEM). It turned out that this memory is allocated for per memory sections page_cgroup arrays. Why does the customer need this? (List the business requirements here) More available memory is always a good thing. How would the customer like to achieve this? (List the functional requirements here) We can reduce this internal fragmentation by splitting the single page_cgroup array into more arrays where each one is well kmalloc aligned. This patch http://thread.gmane.org/gmane.linux.kernel.mm/58765/focus=58940 implements this idea. For each functional requirement listed in question 4, specify how Red Hat and the customer can test to confirm the requirement is successfully implemented. Look at slab statistics to see that there are fewer 2 mb slab objects. Is there already an existing RFE upstream or in Red Hat bugzilla? Not yet. How quickly does this need resolved? (desired target release) minor Does this request meet the RHEL Inclusion criteria (please review) yes List the affected packages kernel Would the customer be able to assist in testing this functionality if implemented? yes