linux/arch/parisc/include/asm/sparsemem.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef ASM_PARISC_SPARSEMEM_H
#define ASM_PARISC_SPARSEMEM_H

/* We have these possible memory map layouts:
 * Astro: 0-3.75, 67.75-68, 4-64
 * zx1: 0-1, 257-260, 4-256
 * Stretch (N-class): 0-2, 4-32, 34-xxx
 */

#define MAX_PHYSMEM_BITS	39	/* 512 GB */
#define SECTION_SIZE_BITS	27	/* 128 MB */

#endif
parisc: Switch from DISCONTIGMEM to SPARSEMEM The commit 1c30844d2dfe ("mm: reclaim small amounts of memory when an external fragmentation event occurs") breaks memory management on a parisc c8000 workstation with this memory layout: 0) Start 0x0000000000000000 End 0x000000003fffffff Size 1024 MB 1) Start 0x0000000100000000 End 0x00000001bfdfffff Size 3070 MB 2) Start 0x0000004040000000 End 0x00000040ffffffff Size 3072 MB With the patch 1c30844d2dfe, the kernel will incorrectly reclaim the first zone when it fills up, ignoring the fact that there are two completely free zones. Basiscally, it limits cache size to 1GiB. The parisc kernel is currently using the DISCONTIGMEM implementation, but isn't NUMA. Avoid this issue or strange work-arounds by switching to the more commonly used SPARSEMEM implementation. Reported-by: Mikulas Patocka <mpatocka@redhat.com> Fixes: 1c30844d2dfe ("mm: reclaim small amounts of memory when an external fragmentation event occurs") Signed-off-by: Helge Deller <deller@gmx.de> 2019-04-09 21:52:35 +02:00			`/* SPDX-License-Identifier: GPL-2.0 */`
			`#ifndef ASM_PARISC_SPARSEMEM_H`
			`#define ASM_PARISC_SPARSEMEM_H`

			`/* We have these possible memory map layouts:`
			`* Astro: 0-3.75, 67.75-68, 4-64`
			`* zx1: 0-1, 257-260, 4-256`
			`* Stretch (N-class): 0-2, 4-32, 34-xxx`
			`*/`

			`#define MAX_PHYSMEM_BITS 39 /* 512 GB */`
			`#define SECTION_SIZE_BITS 27 /* 128 MB */`

			`#endif`