linux-dev/drivers/staging/zsmalloc, branch master

zsmalloc: move it under mm

2014-01-31T00:56:55Z

This patch moves zsmalloc under mm directory. Before that, description will explain why we have needed custom allocator. Zsmalloc is a new slab-based memory allocator for storing compressed pages. It is designed for low fragmentation and high allocation success rate on large object, but <= PAGE_SIZE allocations. zsmalloc differs from the kernel slab allocator in two primary ways to achieve these design goals. zsmalloc never requires high order page allocations to back slabs, or "size classes" in zsmalloc terms. Instead it allows multiple single-order pages to be stitched together into a "zspage" which backs the slab. This allows for higher allocation success rate under memory pressure. Also, zsmalloc allows objects to span page boundaries within the zspage. This allows for lower fragmentation than could be had with the kernel slab allocator for objects between PAGE_SIZE/2 and PAGE_SIZE. With the kernel slab allocator, if a page compresses to 60% of it original size, the memory savings gained through compression is lost in fragmentation because another object of the same size can't be stored in the leftover space. This ability to span pages results in zsmalloc allocations not being directly addressable by the user. The user is given an non-dereferencable handle in response to an allocation request. That handle must be mapped, using zs_map_object(), which returns a pointer to the mapped region that can be used. The mapping is necessary since the object data may reside in two different noncontigious pages. The zsmalloc fulfills the allocation needs for zram perfectly [sjenning@linux.vnet.ibm.com: borrow Seth's quote] Signed-off-by: Minchan Kim Acked-by: Nitin Gupta Reviewed-by: Konrad Rzeszutek Wilk Cc: Bob Liu Cc: Greg Kroah-Hartman Cc: Hugh Dickins Cc: Jens Axboe Cc: Luigi Semenzato Cc: Mel Gorman Cc: Pekka Enberg Cc: Rik van Riel Cc: Seth Jennings Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

staging: delete non-required instances of include

2013-12-17T18:08:14Z

None of these files are actually using any __init type directives and hence don't need to include . Most are just a left over from __devinit and __cpuinit removal, or simply due to code getting copied from one driver to the next. Signed-off-by: Paul Gortmaker Signed-off-by: Greg Kroah-Hartman

zsmalloc: add more comment

2013-12-11T02:20:05Z

This patch adds lots of comments and it will help others to review and enhance. Signed-off-by: Seth Jennings Signed-off-by: Nitin Gupta Signed-off-by: Minchan Kim Signed-off-by: Greg Kroah-Hartman

zsmalloc: add Kconfig for enabling page table method

2013-12-11T02:20:05Z

Zsmalloc has two methods 1) copy-based and 2) pte based to access objects that span two pages. You can see history why we supported two approach from [1]. But it was bad choice that adding hard coding to select arch which want to use pte based method because there are lots of SoC in an architecure and they can have different cache size, CPU speed and so on so it would be better to expose it to user as selectable Kconfig option like Andrew Morton suggested. [1] https://lkml.org/lkml/2012/7/11/58 Acked-by: Nitin Gupta Reviewed-by: Konrad Rzeszutek Wilk Signed-off-by: Minchan Kim Signed-off-by: Greg Kroah-Hartman

staging: zsmalloc: Ensure handle is never 0 on success

2013-11-25T20:52:45Z

zsmalloc encodes a handle using the pfn and an object index. On hardware platforms with physical memory starting at 0x0 the pfn can be 0. This causes the encoded handle to be 0 and is incorrectly interpreted as an allocation failure. This issue affects all current and future SoCs with physical memory starting at 0x0. All MSM8974 SoCs which includes Google Nexus 5 devices are affected. To prevent this false error we ensure that the encoded handle will not be 0 when allocation succeeds. Signed-off-by: Olav Haugan Cc: stable Signed-off-by: Greg Kroah-Hartman

zsmalloc: Fix "map_vm_area" undefined reference errors.

2013-10-11T22:23:13Z

This patch adds a MMU dependency to configure the ZSMALLOC in drivers/staging/zsmalloc/Kconfig. Without this patch, build system can lead to build failure. This was observed during randconfig testing, in which ZSMALLOC was enabled w/o MMU being enabled. Following was the error: LD vmlinux drivers/built-in.o: In function `__zs_map_object': drivers/staging/zsmalloc/zsmalloc-main.c:650: undefined reference to `map_vm_area' make: *** [vmlinux] Error 1 Signed-off-by: Manjunath Goudar Cc: Nitin Gupta Cc: Seth Jennings Cc: Greg Kroah-Hartman Cc: Minchan Kim Cc: Joerg Roedel Cc: devel@driverdev.osuosl.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

staging: zsmalloc: access page->private by using page_private macro

2013-07-23T21:52:19Z

Signed-off-by: Sunghan Suh Signed-off-by: Greg Kroah-Hartman

staging/zsmalloc: Fixed up incorrect formatted comments

2013-05-21T17:30:10Z

The existing comments are using an odd style. Fixed them up to adhere to the StyleGuide. No code changes. Signed-off-by: Sara Bird Signed-off-by: Greg Kroah-Hartman

Staging: Fixes string split across lines in zsmalloc zsmalloc-main

2013-05-20T17:43:10Z

Fixes the following checkpatch warning: WARNING: quoted string split across lines Signed-off-by: Marlies Ruck Signed-off-by: Greg Kroah-Hartman

staging/zsmalloc: don't use pgtable-mapping from modules

2013-04-23T17:34:20Z

Building zsmalloc as a module does not work on ARM because it uses an interface that is not exported: ERROR: "flush_tlb_kernel_range" [drivers/staging/zsmalloc/zsmalloc.ko] undefined! Since this is only used as a performance optimization and only on ARM, we can avoid the problem simply by not using that optimization when building zsmalloc it is a loadable module. flush_tlb_kernel_range is often an inline function, but out of the architectures that use an extern function, only powerpc exports it. Signed-off-by: Arnd Bergmann Cc: Greg Kroah-Hartman Cc: Seth Jennings Cc: Nitin Gupta Signed-off-by: Greg Kroah-Hartman