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Patch series "mm,thp,shm: limit shmem THP alloc gfp_mask", v6.
The allocation flags of anonymous transparent huge pages can be controlled
through the files in /sys/kernel/mm/transparent_hugepage/defrag, which can
help the system from getting bogged down in the page reclaim and
compaction code when many THPs are getting allocated simultaneously.
However, the gfp_mask for shmem THP allocations were not limited by those
configuration settings, and some workloads ended up with all CPUs stuck on
the LRU lock in the page reclaim code, trying to allocate dozens of THPs
simultaneously.
This patch applies the same configurated limitation of THPs to shmem
hugepage allocations, to prevent that from happening.
This way a THP defrag setting of "never" or "defer+madvise" will result in
quick allocation failures without direct reclaim when no 2MB free pages
are available.
With this patch applied, THP allocations for tmpfs will be a little more
aggressive than today for files mmapped with MADV_HUGEPAGE, and a little
less aggressive for files that are not mmapped or mapped without that
flag.
This patch (of 4):
The allocation flags of anonymous transparent huge pages can be controlled
through the files in /sys/kernel/mm/transparent_hugepage/defrag, which can
help the system from getting bogged down in the page reclaim and
compaction code when many THPs are getting allocated simultaneously.
However, the gfp_mask for shmem THP allocations were not limited by those
configuration settings, and some workloads ended up with all CPUs stuck on
the LRU lock in the page reclaim code, trying to allocate dozens of THPs
simultaneously.
This patch applies the same configurated limitation of THPs to shmem
hugepage allocations, to prevent that from happening.
Controlling the gfp_mask of THP allocations through the knobs in sysfs
allows users to determine the balance between how aggressively the system
tries to allocate THPs at fault time, and how much the application may end
up stalling attempting those allocations.
This way a THP defrag setting of "never" or "defer+madvise" will result in
quick allocation failures without direct reclaim when no 2MB free pages
are available.
With this patch applied, THP allocations for tmpfs will be a little more
aggressive than today for files mmapped with MADV_HUGEPAGE, and a little
less aggressive for files that are not mmapped or mapped without that
flag.
Link: https://lkml.kernel.org/r/20201124194925.623931-1-riel@surriel.com
Link: https://lkml.kernel.org/r/20201124194925.623931-2-riel@surriel.com
Signed-off-by: Rik van Riel <riel@surriel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Xu Yu <xuyu@linux.alibaba.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Overhaul multi-page lookups for THP", v4.
This THP prep patchset changes several page cache iteration APIs to only
return head pages.
- It's only possible to tag head pages in the page cache, so only
return head pages, not all their subpages.
- Factor a lot of common code out of the various batch lookup routines
- Add mapping_seek_hole_data()
- Unify find_get_entries() and pagevec_lookup_entries()
- Make find_get_entries only return head pages, like find_get_entry().
These are only loosely connected, but they seem to make sense together as
a series.
This patch (of 14):
Pagecache tags are used for dirty page writeback. Since dirtiness is
tracked on a per-THP basis, we only want to return the head page rather
than each subpage of a tagged page. All the filesystems which use huge
pages today are in-memory, so there are no tagged huge pages today.
Link: https://lkml.kernel.org/r/20201112212641.27837-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull Kbuild updates from Masahiro Yamada:
- Fix false-positive build warnings for ARCH=ia64 builds
- Optimize dictionary size for module compression with xz
- Check the compiler and linker versions in Kconfig
- Fix misuse of extra-y
- Support DWARF v5 debug info
- Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x
exceeded the limit
- Add generic syscall{tbl,hdr}.sh for cleanups across arches
- Minor cleanups of genksyms
- Minor cleanups of Kconfig
* tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (38 commits)
initramfs: Remove redundant dependency of RD_ZSTD on BLK_DEV_INITRD
kbuild: remove deprecated 'always' and 'hostprogs-y/m'
kbuild: parse C= and M= before changing the working directory
kbuild: reuse this-makefile to define abs_srctree
kconfig: unify rule of config, menuconfig, nconfig, gconfig, xconfig
kconfig: omit --oldaskconfig option for 'make config'
kconfig: fix 'invalid option' for help option
kconfig: remove dead code in conf_askvalue()
kconfig: clean up nested if-conditionals in check_conf()
kconfig: Remove duplicate call to sym_get_string_value()
Makefile: Remove # characters from compiler string
Makefile: reuse CC_VERSION_TEXT
kbuild: check the minimum linker version in Kconfig
kbuild: remove ld-version macro
scripts: add generic syscallhdr.sh
scripts: add generic syscalltbl.sh
arch: syscalls: remove $(srctree)/ prefix from syscall tables
arch: syscalls: add missing FORCE and fix 'targets' to make if_changed work
gen_compile_commands: prune some directories
kbuild: simplify access to the kernel's version
...
Pull ext4 updates from Ted Ts'o:
"Miscellaneous ext4 cleanups and bug fixes. Pretty boring this cycle..."
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: add .kunitconfig fragment to enable ext4-specific tests
ext: EXT4_KUNIT_TESTS should depend on EXT4_FS instead of selecting it
ext4: reset retry counter when ext4_alloc_file_blocks() makes progress
ext4: fix potential htree index checksum corruption
ext4: factor out htree rep invariant check
ext4: Change list_for_each* to list_for_each_entry*
ext4: don't try to processed freed blocks until mballoc is initialized
ext4: use DEFINE_MUTEX() for mutex lock
Pull PCI updates from Bjorn Helgaas:
"Enumeration:
- Remove unnecessary locking around _OSC (Bjorn Helgaas)
- Clarify message about _OSC failure (Bjorn Helgaas)
- Remove notification of PCIe bandwidth changes (Bjorn Helgaas)
- Tidy checking of syscall user config accessors (Heiner Kallweit)
Resource management:
- Decline to resize resources if boot config must be preserved (Ard
Biesheuvel)
- Fix pci_register_io_range() memory leak (Geert Uytterhoeven)
Error handling (Keith Busch):
- Clear error status from the correct device
- Retain error recovery status so drivers can use it after reset
- Log the type of Port (Root or Switch Downstream) that we reset
- Always request a reset for Downstream Ports in frozen state
Endpoint framework and NTB (Kishon Vijay Abraham I):
- Make *_get_first_free_bar() take into account 64 bit BAR
- Add helper API to get the 'next' unreserved BAR
- Make *_free_bar() return error codes on failure
- Remove unused pci_epf_match_device()
- Add support to associate secondary EPC with EPF
- Add support in configfs to associate two EPCs with EPF
- Add pci_epc_ops to map MSI IRQ
- Add pci_epf_ops to expose function-specific attrs
- Allow user to create sub-directory of 'EPF Device' directory
- Implement ->msi_map_irq() ops for cadence
- Configure LM_EP_FUNC_CFG based on epc->function_num_map for cadence
- Add EP function driver to provide NTB functionality
- Add support for EPF PCI Non-Transparent Bridge
- Add specification for PCI NTB function device
- Add PCI endpoint NTB function user guide
- Add configfs binding documentation for pci-ntb endpoint function
Broadcom STB PCIe controller driver:
- Add support for BCM4908 and external PERST# signal controller
(Rafał Miłecki)
Cadence PCIe controller driver:
- Retrain Link to work around Gen2 training defect (Nadeem Athani)
- Fix merge botch in cdns_pcie_host_map_dma_ranges() (Krzysztof
Wilczyński)
Freescale Layerscape PCIe controller driver:
- Add LX2160A rev2 EP mode support (Hou Zhiqiang)
- Convert to builtin_platform_driver() (Michael Walle)
MediaTek PCIe controller driver:
- Fix OF node reference leak (Krzysztof Wilczyński)
Microchip PolarFlare PCIe controller driver:
- Add Microchip PolarFire PCIe controller driver (Daire McNamara)
Qualcomm PCIe controller driver:
- Use PHY_REFCLK_USE_PAD only for ipq8064 (Ansuel Smith)
- Add support for ddrss_sf_tbu clock for sm8250 (Dmitry Baryshkov)
Renesas R-Car PCIe controller driver:
- Drop PCIE_RCAR config option (Lad Prabhakar)
- Always allocate MSI addresses in 32bit space (Marek Vasut)
Rockchip PCIe controller driver:
- Add FriendlyARM NanoPi M4B DT binding (Chen-Yu Tsai)
- Make 'ep-gpios' DT property optional (Chen-Yu Tsai)
Synopsys DesignWare PCIe controller driver:
- Work around ECRC configuration hardware defect (Vidya Sagar)
- Drop support for config space in DT 'ranges' (Rob Herring)
- Change size to u64 for EP outbound iATU (Shradha Todi)
- Add upper limit address for outbound iATU (Shradha Todi)
- Make dw_pcie ops optional (Jisheng Zhang)
- Remove unnecessary dw_pcie_ops from al driver (Jisheng Zhang)
Xilinx Versal CPM PCIe controller driver:
- Fix OF node reference leak (Pan Bian)
Miscellaneous:
- Remove tango host controller driver (Arnd Bergmann)
- Remove IRQ handler & data together (altera-msi, brcmstb, dwc)
(Martin Kaiser)
- Fix xgene-msi race in installing chained IRQ handler (Martin
Kaiser)
- Apply CONFIG_PCI_DEBUG to entire drivers/pci hierarchy (Junhao He)
- Fix pci-bridge-emul array overruns (Russell King)
- Remove obsolete uses of WARN_ON(in_interrupt()) (Sebastian Andrzej
Siewior)"
* tag 'pci-v5.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (69 commits)
PCI: qcom: Use PHY_REFCLK_USE_PAD only for ipq8064
PCI: qcom: Add support for ddrss_sf_tbu clock
dt-bindings: PCI: qcom: Document ddrss_sf_tbu clock for sm8250
PCI: al: Remove useless dw_pcie_ops
PCI: dwc: Don't assume the ops in dw_pcie always exist
PCI: dwc: Add upper limit address for outbound iATU
PCI: dwc: Change size to u64 for EP outbound iATU
PCI: dwc: Drop support for config space in 'ranges'
PCI: layerscape: Convert to builtin_platform_driver()
PCI: layerscape: Add LX2160A rev2 EP mode support
dt-bindings: PCI: layerscape: Add LX2160A rev2 compatible strings
PCI: dwc: Work around ECRC configuration issue
PCI/portdrv: Report reset for frozen channel
PCI/AER: Specify the type of Port that was reset
PCI/ERR: Retain status from error notification
PCI/AER: Clear AER status from Root Port when resetting Downstream Port
PCI/ERR: Clear status of the reporting device
dt-bindings: arm: rockchip: Add FriendlyARM NanoPi M4B
PCI: rockchip: Make 'ep-gpios' DT property optional
Documentation: PCI: Add PCI endpoint NTB function user guide
...
Pull nds32 updates from Greentime Hu:
"Code clean-up and refinement"
* tag 'nds32-for-linux-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux:
nds32: Fix bogus reference to <asm/procinfo.h>
nds32: use get_kernel_nofault in dump_mem
nds32: remove dump_instr
nds32: configs: Cleanup CONFIG_CROSS_COMPILE
nds32: Replace <linux/clk-provider.h> by <linux/of_clk.h>
Use the proper get_kernel_nofault helper to access an unsafe kernel
pointer without faulting instead of playing with set_fs and get_user.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Nick Hu <nickhu@andestech.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
dump_inst has a return before actually doing anything, so just drop the
whole thing.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Nick Hu <nickhu@andestech.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
CONFIG_CROSS_COMPILE is gone since commit f1089c92da ("kbuild: remove
CONFIG_CROSS_COMPILE support").
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Greentime Hu <green.hu@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
The Andes platform code is not a clock provider, and just needs to call
of_clk_init().
Hence it can include <linux/of_clk.h> instead of <linux/clk-provider.h>.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greentime Hu <green.hu@gmail.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
Pull x86 irq entry updates from Thomas Gleixner:
"The irq stack switching was moved out of the ASM entry code in course
of the entry code consolidation. It ended up being suboptimal in
various ways.
This reworks the X86 irq stack handling:
- Make the stack switching inline so the stackpointer manipulation is
not longer at an easy to find place.
- Get rid of the unnecessary indirect call.
- Avoid the double stack switching in interrupt return and reuse the
interrupt stack for softirq handling.
- A objtool fix for CONFIG_FRAME_POINTER=y builds where it got
confused about the stack pointer manipulation"
* tag 'x86-entry-2021-02-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
objtool: Fix stack-swizzle for FRAME_POINTER=y
um: Enforce the usage of asm-generic/softirq_stack.h
x86/softirq/64: Inline do_softirq_own_stack()
softirq: Move do_softirq_own_stack() to generic asm header
softirq: Move __ARCH_HAS_DO_SOFTIRQ to Kconfig
x86: Select CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
x86/softirq: Remove indirection in do_softirq_own_stack()
x86/entry: Use run_sysvec_on_irqstack_cond() for XEN upcall
x86/entry: Convert device interrupts to inline stack switching
x86/entry: Convert system vectors to irq stack macro
x86/irq: Provide macro for inlining irq stack switching
x86/apic: Split out spurious handling code
x86/irq/64: Adjust the per CPU irq stack pointer by 8
x86/irq: Sanitize irq stack tracking
x86/entry: Fix instrumentation annotation
Merge misc updates from Andrew Morton:
"A few small subsystems and some of MM.
172 patches.
Subsystems affected by this patch series: hexagon, scripts, ntfs,
ocfs2, vfs, and mm (slab-generic, slab, slub, debug, pagecache, swap,
memcg, pagemap, mprotect, mremap, page-reporting, vmalloc, kasan,
pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
mempolicy, oom-kill, hugetlbfs, and migration)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (172 commits)
mm/migrate: remove unneeded semicolons
hugetlbfs: remove unneeded return value of hugetlb_vmtruncate()
hugetlbfs: fix some comment typos
hugetlbfs: correct some obsolete comments about inode i_mutex
hugetlbfs: make hugepage size conversion more readable
hugetlbfs: remove meaningless variable avoid_reserve
hugetlbfs: correct obsolete function name in hugetlbfs_read_iter()
hugetlbfs: use helper macro default_hstate in init_hugetlbfs_fs
hugetlbfs: remove useless BUG_ON(!inode) in hugetlbfs_setattr()
hugetlbfs: remove special hugetlbfs_set_page_dirty()
mm/hugetlb: change hugetlb_reserve_pages() to type bool
mm, oom: fix a comment in dump_task()
mm/mempolicy: use helper range_in_vma() in queue_pages_test_walk()
numa balancing: migrate on fault among multiple bound nodes
mm, compaction: make fast_isolate_freepages() stay within zone
mm/compaction: fix misbehaviors of fast_find_migrateblock()
mm/compaction: correct deferral logic for proactive compaction
mm/compaction: remove duplicated VM_BUG_ON_PAGE !PageLocked
mm/compaction: remove rcu_read_lock during page compaction
z3fold: simplify the zhdr initialization code in init_z3fold_page()
...
Now, NUMA balancing can only optimize the page placement among the NUMA
nodes if the default memory policy is used. Because the memory policy
specified explicitly should take precedence. But this seems too strict in
some situations. For example, on a system with 4 NUMA nodes, if the
memory of an application is bound to the node 0 and 1, NUMA balancing can
potentially migrate the pages between the node 0 and 1 to reduce
cross-node accessing without breaking the explicit memory binding policy.
So in this patch, we add MPOL_F_NUMA_BALANCING mode flag to
set_mempolicy() when mode is MPOL_BIND. With the flag specified, NUMA
balancing will be enabled within the thread to optimize the page placement
within the constrains of the specified memory binding policy. With the
newly added flag, the NUMA balancing control mechanism becomes,
- sysctl knob numa_balancing can enable/disable the NUMA balancing
globally.
- even if sysctl numa_balancing is enabled, the NUMA balancing will be
disabled for the memory areas or applications with the explicit
memory policy by default.
- MPOL_F_NUMA_BALANCING can be used to enable the NUMA balancing for
the applications when specifying the explicit memory policy
(MPOL_BIND).
Various page placement optimization based on the NUMA balancing can be
done with these flags. As the first step, in this patch, if the memory of
the application is bound to multiple nodes (MPOL_BIND), and in the hint
page fault handler the accessing node are in the policy nodemask, the page
will be tried to be migrated to the accessing node to reduce the
cross-node accessing.
If the newly added MPOL_F_NUMA_BALANCING flag is specified by an
application on an old kernel version without its support, set_mempolicy()
will return -1 and errno will be set to EINVAL. The application can use
this behavior to run on both old and new kernel versions.
And if the MPOL_F_NUMA_BALANCING flag is specified for the mode other than
MPOL_BIND, set_mempolicy() will return -1 and errno will be set to EINVAL
as before. Because we don't support optimization based on the NUMA
balancing for these modes.
In the previous version of the patch, we tried to reuse MPOL_MF_LAZY for
mbind(). But that flag is tied to MPOL_MF_MOVE.*, so it seems not a good
API/ABI for the purpose of the patch.
And because it's not clear whether it's necessary to enable NUMA balancing
for a specific memory area inside an application, so we only add the flag
at the thread level (set_mempolicy()) instead of the memory area level
(mbind()). We can do that when it become necessary.
To test the patch, we run a test case as follows on a 4-node machine with
192 GB memory (48 GB per node).
1. Change pmbench memory accessing benchmark to call set_mempolicy()
to bind its memory to node 1 and 3 and enable NUMA balancing. Some
related code snippets are as follows,
#include <numaif.h>
#include <numa.h>
struct bitmask *bmp;
int ret;
bmp = numa_parse_nodestring("1,3");
ret = set_mempolicy(MPOL_BIND | MPOL_F_NUMA_BALANCING,
bmp->maskp, bmp->size + 1);
/* If MPOL_F_NUMA_BALANCING isn't supported, fall back to MPOL_BIND */
if (ret < 0 && errno == EINVAL)
ret = set_mempolicy(MPOL_BIND, bmp->maskp, bmp->size + 1);
if (ret < 0) {
perror("Failed to call set_mempolicy");
exit(-1);
}
2. Run a memory eater on node 3 to use 40 GB memory before running pmbench.
3. Run pmbench with 64 processes, the working-set size of each process
is 640 MB, so the total working-set size is 64 * 640 MB = 40 GB. The
CPU and the memory (as in step 1.) of all pmbench processes is bound
to node 1 and 3. So, after CPU usage is balanced, some pmbench
processes run on the CPUs of the node 3 will access the memory of
the node 1.
4. After the pmbench processes run for 100 seconds, kill the memory
eater. Now it's possible for some pmbench processes to migrate
their pages from node 1 to node 3 to reduce cross-node accessing.
Test results show that, with the patch, the pages can be migrated from
node 1 to node 3 after killing the memory eater, and the pmbench score
can increase about 17.5%.
Link: https://lkml.kernel.org/r/20210120061235.148637-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Compaction always operates on pages from a single given zone when
isolating both pages to migrate and freepages. Pageblock boundaries are
intersected with zone boundaries to be safe in case zone starts or ends in
the middle of pageblock. The use of pageblock_pfn_to_page() protects
against non-contiguous pageblocks.
The functions fast_isolate_freepages() and fast_isolate_around() don't
currently protect the fast freepage isolation thoroughly enough against
these corner cases, and can result in freepage isolation operate outside
of zone boundaries:
- in fast_isolate_freepages() if we get a pfn from the first pageblock
of a zone that starts in the middle of that pageblock, 'highest' can
be a pfn outside of the zone.
If we fail to isolate anything in this function, we may then call
fast_isolate_around() on a pfn outside of the zone and there
effectively do a set_pageblock_skip(page_to_pfn(highest)) which may
currently hit a VM_BUG_ON() in some configurations
- fast_isolate_around() checks only the zone end boundary and not
beginning, nor that the pageblock is contiguous (with
pageblock_pfn_to_page()) so it's possible that we end up calling
isolate_freepages_block() on a range of pfn's from two different
zones and end up e.g. isolating freepages under the wrong zone's
lock.
This patch should fix the above issues.
Link: https://lkml.kernel.org/r/20210217173300.6394-1-vbabka@suse.cz
Fixes: 5a811889de ("mm, compaction: use free lists to quickly locate a migration target")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In the fast_find_migrateblock(), it iterates ocer the freelist to find the
proper pageblock. But there are some misbehaviors.
First, if the page we found is equal to cc->migrate_pfn, it is considered
that we didn't find a suitable pageblock. Secondly, if the loop was
terminated because order is less than PAGE_ALLOC_COSTLY_ORDER, it could be
considered that we found a suitable one. Thirdly, if the skip bit is set
on the page block and we goto continue, it doesn't check nr_scanned.
Fourthly, if the page block's skip bit is set, it checks that page block
is the last of list, which is unnecessary.
Link: https://lkml.kernel.org/r/20210128130411.6125-1-vvghjk1234@gmail.com
Fixes: 70b44595ea ("mm, compaction: use free lists to quickly locate a migration source")
Signed-off-by: Wonhyuk Yang <vvghjk1234@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
should_proactive_compact_node() returns true when sum of the weighted
fragmentation score of all the zones in the node is greater than the
wmark_high of compaction, which then triggers the proactive compaction
that operates on the individual zones of the node. But proactive
compaction runs on the zone only when its weighted fragmentation score
is greater than wmark_low(=wmark_high - 10).
This means that the sum of the weighted fragmentation scores of all the
zones can exceed the wmark_high but individual weighted fragmentation zone
scores can still be less than wmark_low which makes the unnecessary
trigger of the proactive compaction only to return doing nothing.
Issue with the return of proactive compaction with out even trying is its
deferral. It is simply deferred for 1 << COMPACT_MAX_DEFER_SHIFT if the
scores across the proactive compaction is same, thinking that compaction
didn't make any progress but in reality it didn't even try. With the
delay between successive retries for proactive compaction is 500msec, it
can result into the deferral for ~30sec with out even trying the proactive
compaction.
Test scenario is that: compaction_proactiveness=50 thus the wmark_low = 50
and wmark_high = 60. System have 2 zones(Normal and Movable) with sizes
5GB and 6GB respectively. After opening some apps on the android, the
weighted fragmentation scores of these zones are 47 and 49 respectively.
Since the sum of these fragmentation scores are above the wmark_high which
triggers the proactive compaction and there since the individual zones
weighted fragmentation scores are below wmark_low, it returns without
trying the proactive compaction. As a result the weighted fragmentation
scores of the zones are still 47 and 49 which makes the existing logic to
defer the compaction thinking that noprogress is made across the
compaction.
Fix this by checking just zone fragmentation score, not the weighted, in
__compact_finished() and use the zones weighted fragmentation score in
fragmentation_score_node(). In the test case above, If the weighted
average of is above wmark_high, then individual score (not adjusted) of
atleast one zone has to be above wmark_high. Thus it avoids the
unnecessary trigger and deferrals of the proactive compaction.
Link: https://lkml.kernel.org/r/1610989938-31374-1-git-send-email-charante@codeaurora.org
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nitin Gupta <ngupta@nitingupta.dev>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
