forked from Minki/linux
mm, page_alloc: extend kernelcore and movablecore for percent
Both kernelcore= and movablecore= can be used to define the amount of ZONE_NORMAL and ZONE_MOVABLE on a system, respectively. This requires the system memory capacity to be known when specifying the command line, however. This introduces the ability to define both kernelcore= and movablecore= as a percentage of total system memory. This is convenient for systems software that wants to define the amount of ZONE_MOVABLE, for example, as a proportion of a system's memory rather than a hardcoded byte value. To define the percentage, the final character of the parameter should be a '%'. mhocko: "why is anyone using these options nowadays?" rientjes: : : Fragmentation of non-__GFP_MOVABLE pages due to low on memory : situations can pollute most pageblocks on the system, as much as 1GB of : slab being fragmented over 128GB of memory, for example. When the : amount of kernel memory is well bounded for certain systems, it is : better to aggressively reclaim from existing MIGRATE_UNMOVABLE : pageblocks rather than eagerly fallback to others. : : We have additional patches that help with this fragmentation if you're : interested, specifically kcompactd compaction of MIGRATE_UNMOVABLE : pageblocks triggered by fallback of non-__GFP_MOVABLE allocations and : draining of pcp lists back to the zone free area to prevent stranding. [rientjes@google.com: updates] Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1802131700160.71590@chino.kir.corp.google.com Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1802121622470.179479@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Rientjes
Linus Torvalds
parent
31286a8484
commit
a5c6d65093
@ -1840,30 +1840,29 @@
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keepinitrd [HW,ARM]
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kernelcore= [KNL,X86,IA-64,PPC]
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Format: nn[KMGTPE] | "mirror"
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This parameter
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specifies the amount of memory usable by the kernel
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for non-movable allocations. The requested amount is
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spread evenly throughout all nodes in the system. The
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remaining memory in each node is used for Movable
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pages. In the event, a node is too small to have both
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kernelcore and Movable pages, kernelcore pages will
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take priority and other nodes will have a larger number
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of Movable pages. The Movable zone is used for the
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allocation of pages that may be reclaimed or moved
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by the page migration subsystem. This means that
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HugeTLB pages may not be allocated from this zone.
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Note that allocations like PTEs-from-HighMem still
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use the HighMem zone if it exists, and the Normal
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Format: nn[KMGTPE] | nn% | "mirror"
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This parameter specifies the amount of memory usable by
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the kernel for non-movable allocations. The requested
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amount is spread evenly throughout all nodes in the
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system as ZONE_NORMAL. The remaining memory is used for
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movable memory in its own zone, ZONE_MOVABLE. In the
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event, a node is too small to have both ZONE_NORMAL and
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ZONE_MOVABLE, kernelcore memory will take priority and
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other nodes will have a larger ZONE_MOVABLE.
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ZONE_MOVABLE is used for the allocation of pages that
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may be reclaimed or moved by the page migration
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subsystem. Note that allocations like PTEs-from-HighMem
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still use the HighMem zone if it exists, and the Normal
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zone if it does not.
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Instead of specifying the amount of memory (nn[KMGTPE]),
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you can specify "mirror" option. In case "mirror"
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It is possible to specify the exact amount of memory in
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the form of "nn[KMGTPE]", a percentage of total system
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memory in the form of "nn%", or "mirror". If "mirror"
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option is specified, mirrored (reliable) memory is used
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for non-movable allocations and remaining memory is used
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for Movable pages. nn[KMGTPE] and "mirror" are exclusive,
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so you can NOT specify nn[KMGTPE] and "mirror" at the same
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time.
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for Movable pages. "nn[KMGTPE]", "nn%", and "mirror"
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are exclusive, so you cannot specify multiple forms.
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kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
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Format: <Controller#>[,poll interval]
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@ -2377,13 +2376,14 @@
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mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
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reporting absolute coordinates, such as tablets
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movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
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is similar to kernelcore except it specifies the
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amount of memory used for migratable allocations.
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If both kernelcore and movablecore is specified,
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then kernelcore will be at *least* the specified
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value but may be more. If movablecore on its own
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is specified, the administrator must be careful
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movablecore= [KNL,X86,IA-64,PPC]
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Format: nn[KMGTPE] | nn%
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This parameter is the complement to kernelcore=, it
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specifies the amount of memory used for migratable
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allocations. If both kernelcore and movablecore is
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specified, then kernelcore will be at *least* the
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specified value but may be more. If movablecore on its
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own is specified, the administrator must be careful
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that the amount of memory usable for all allocations
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is not too small.
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@ -273,7 +273,9 @@ static unsigned long __meminitdata dma_reserve;
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static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
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static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
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static unsigned long __initdata required_kernelcore;
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static unsigned long required_kernelcore_percent __initdata;
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static unsigned long __initdata required_movablecore;
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static unsigned long required_movablecore_percent __initdata;
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static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
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static bool mirrored_kernelcore;
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@ -6571,7 +6573,18 @@ static void __init find_zone_movable_pfns_for_nodes(void)
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}
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/*
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* If movablecore=nn[KMG] was specified, calculate what size of
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* If kernelcore=nn% or movablecore=nn% was specified, calculate the
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* amount of necessary memory.
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*/
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if (required_kernelcore_percent)
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required_kernelcore = (totalpages * 100 * required_kernelcore_percent) /
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10000UL;
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if (required_movablecore_percent)
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required_movablecore = (totalpages * 100 * required_movablecore_percent) /
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10000UL;
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/*
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* If movablecore= was specified, calculate what size of
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* kernelcore that corresponds so that memory usable for
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* any allocation type is evenly spread. If both kernelcore
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* and movablecore are specified, then the value of kernelcore
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@ -6811,18 +6824,30 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
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zero_resv_unavail();
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}
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static int __init cmdline_parse_core(char *p, unsigned long *core)
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static int __init cmdline_parse_core(char *p, unsigned long *core,
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unsigned long *percent)
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{
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unsigned long long coremem;
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char *endptr;
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if (!p)
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return -EINVAL;
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coremem = memparse(p, &p);
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*core = coremem >> PAGE_SHIFT;
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/* Value may be a percentage of total memory, otherwise bytes */
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coremem = simple_strtoull(p, &endptr, 0);
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if (*endptr == '%') {
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/* Paranoid check for percent values greater than 100 */
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WARN_ON(coremem > 100);
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/* Paranoid check that UL is enough for the coremem value */
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WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
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*percent = coremem;
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} else {
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coremem = memparse(p, &p);
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/* Paranoid check that UL is enough for the coremem value */
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WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
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*core = coremem >> PAGE_SHIFT;
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*percent = 0UL;
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}
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return 0;
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}
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@ -6838,7 +6863,8 @@ static int __init cmdline_parse_kernelcore(char *p)
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return 0;
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}
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return cmdline_parse_core(p, &required_kernelcore);
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return cmdline_parse_core(p, &required_kernelcore,
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&required_kernelcore_percent);
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}
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/*
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@ -6847,7 +6873,8 @@ static int __init cmdline_parse_kernelcore(char *p)
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*/
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static int __init cmdline_parse_movablecore(char *p)
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{
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return cmdline_parse_core(p, &required_movablecore);
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return cmdline_parse_core(p, &required_movablecore,
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&required_movablecore_percent);
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}
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early_param("kernelcore", cmdline_parse_kernelcore);
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