kernel/linux.git/mm/cma.c, branch v6.2

Revert "mm/cma.c: remove redundant cma_mutex lock"

2022-05-13T22:11:26+00:00

This reverts commit a4efc174b382fcdb which introduced a regression issue that when there're multiple processes allocating dma memory in parallel by calling dma_alloc_coherent(), it may fail sometimes as follows: Error log: cma: cma_alloc: linux,cma: alloc failed, req-size: 148 pages, ret: -16 cma: number of available pages: 3@125+20@172+12@236+4@380+32@736+17@2287+23@2473+20@36076+99@40477+108@40852+44@41108+20@41196+108@41364+108@41620+ 108@42900+108@43156+483@44061+1763@45341+1440@47712+20@49324+20@49388+5076@49452+2304@55040+35@58141+20@58220+20@58284+ 7188@58348+84@66220+7276@66452+227@74525+6371@75549=> 33161 free of 81920 total pages When issue happened, we saw there were still 33161 pages (129M) free CMA memory and a lot available free slots for 148 pages in CMA bitmap that we want to allocate. When dumping memory info, we found that there was also ~342M normal memory, but only 1352K CMA memory left in buddy system while a lot of pageblocks were isolated. Memory info log: Normal free:351096kB min:30000kB low:37500kB high:45000kB reserved_highatomic:0KB active_anon:98060kB inactive_anon:98948kB active_file:60864kB inactive_file:31776kB unevictable:0kB writepending:0kB present:1048576kB managed:1018328kB mlocked:0kB bounce:0kB free_pcp:220kB local_pcp:192kB free_cma:1352kB lowmem_reserve[]: 0 0 0 Normal: 78*4kB (UECI) 1772*8kB (UMECI) 1335*16kB (UMECI) 360*32kB (UMECI) 65*64kB (UMCI) 36*128kB (UMECI) 16*256kB (UMCI) 6*512kB (EI) 8*1024kB (UEI) 4*2048kB (MI) 8*4096kB (EI) 8*8192kB (UI) 3*16384kB (EI) 8*32768kB (M) = 489288kB The root cause of this issue is that since commit a4efc174b382 ("mm/cma.c: remove redundant cma_mutex lock"), CMA supports concurrent memory allocation. It's possible that the memory range process A trying to alloc has already been isolated by the allocation of process B during memory migration. The problem here is that the memory range isolated during one allocation by start_isolate_page_range() could be much bigger than the real size we want to alloc due to the range is aligned to MAX_ORDER_NR_PAGES. Taking an ARMv7 platform with 1G memory as an example, when MAX_ORDER_NR_PAGES is big (e.g. 32M with max_order 14) and CMA memory is relatively small (e.g. 128M), there're only 4 MAX_ORDER slot, then it's very easy that all CMA memory may have already been isolated by other processes when one trying to allocate memory using dma_alloc_coherent(). Since current CMA code will only scan one time of whole available CMA memory, then dma_alloc_coherent() may easy fail due to contention with other processes. This patch simply falls back to the original method that using cma_mutex to make alloc_contig_range() run sequentially to avoid the issue. Link: https://lkml.kernel.org/r/20220509094551.3596244-1-aisheng.dong@nxp.com Link: https://lore.kernel.org/all/20220315144521.3810298-2-aisheng.dong@nxp.com/ Fixes: a4efc174b382 ("mm/cma.c: remove redundant cma_mutex lock") Signed-off-by: Dong Aisheng Acked-by: Minchan Kim Acked-by: David Hildenbrand Cc: Marek Szyprowski Cc: Lecopzer Chen Cc: Vlastimil Babka Cc: [5.11+] Signed-off-by: Andrew Morton

mm/cma: provide option to opt out from exposing pages on activation failure

2022-03-22T22:57:09+00:00

Patch series "powerpc/fadump: handle CMA activation failure appropriately", v3. Commit 072355c1cf2d ("mm/cma: expose all pages to the buddy if activation of an area fails") started exposing all pages to buddy allocator on CMA activation failure. But there can be CMA users that want to handle the reserved memory differently on CMA allocation failure. Provide an option to opt out from exposing pages to buddy for such cases. Link: https://lkml.kernel.org/r/20220117075246.36072-1-hbathini@linux.ibm.com Link: https://lkml.kernel.org/r/20220117075246.36072-2-hbathini@linux.ibm.com Signed-off-by: Hari Bathini Reviewed-by: David Hildenbrand Cc: Oscar Salvador Cc: Mike Kravetz Cc: Mahesh Salgaonkar Cc: Sourabh Jain Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

cma: factor out minimum alignment requirement

2022-03-22T22:57:05+00:00

Patch series "mm: enforce pageblock_order < MAX_ORDER". Having pageblock_order >= MAX_ORDER seems to be able to happen in corner cases and some parts of the kernel are not prepared for it. For example, Aneesh has shown [1] that such kernels can be compiled on ppc64 with 64k base pages by setting FORCE_MAX_ZONEORDER=8, which will run into a WARN_ON_ONCE(order >= MAX_ORDER) in comapction code right during boot. We can get pageblock_order >= MAX_ORDER when the default hugetlb size is bigger than the maximum allocation granularity of the buddy, in which case we are no longer talking about huge pages but instead gigantic pages. Having pageblock_order >= MAX_ORDER can only make alloc_contig_range() of such gigantic pages more likely to succeed. Reliable use of gigantic pages either requires boot time allcoation or CMA, no need to overcomplicate some places in the kernel to optimize for corner cases that are broken in other areas of the kernel. This patch (of 2): Let's enforce pageblock_order < MAX_ORDER and simplify. Especially patch #1 can be regarded a cleanup before: [PATCH v5 0/6] Use pageblock_order for cma and alloc_contig_range alignment. [2] [1] https://lkml.kernel.org/r/87r189a2ks.fsf@linux.ibm.com [2] https://lkml.kernel.org/r/20220211164135.1803616-1-zi.yan@sent.com Link: https://lkml.kernel.org/r/20220214174132.219303-2-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Zi Yan Acked-by: Rob Herring Cc: Aneesh Kumar K.V Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Frank Rowand Cc: Michael S. Tsirkin Cc: Christoph Hellwig Cc: Marek Szyprowski Cc: Robin Murphy Cc: Minchan Kim Cc: Vlastimil Babka Cc: John Garry via iommu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memblock: rename memblock_free to memblock_phys_free

2021-11-06T20:30:41+00:00

Since memblock_free() operates on a physical range, make its name reflect it and rename it to memblock_phys_free(), so it will be a logical counterpart to memblock_phys_alloc(). The callers are updated with the below semantic patch: @@ expression addr; expression size; @@ - memblock_free(addr, size); + memblock_phys_free(addr, size); Link: https://lkml.kernel.org/r/20210930185031.18648-6-rppt@kernel.org Signed-off-by: Mike Rapoport Cc: Christophe Leroy Cc: Juergen Gross Cc: Shahab Vahedi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/cma: add cma_pages_valid to determine if pages are in CMA

2021-11-06T20:30:39+00:00

Add new interface cma_pages_valid() which indicates if the specified pages are part of a CMA region. This interface will be used in a subsequent patch by hugetlb code. In order to keep the same amount of DEBUG information, a pr_debug() call was added to cma_pages_valid(). In the case where the page passed to cma_release is not in cma region, the debug message will be printed from cma_pages_valid as opposed to cma_release. Link: https://lkml.kernel.org/r/20211007181918.136982-3-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz Acked-by: David Hildenbrand Reviewed-by: Oscar Salvador Cc: "Aneesh Kumar K . V" Cc: David Rientjes Cc: Michal Hocko Cc: Muchun Song Cc: Naoya Horiguchi Cc: Nghia Le Cc: Zi Yan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: use proper type for cma_[alloc|release]

2021-05-05T18:27:24+00:00

size_t in cma_alloc is confusing since it makes people think it's byte count, not pages. Change it to unsigned long[1]. The unsigned int in cma_release is also not right so change it. Since we have unsigned long in cma_release, free_contig_range should also respect it. [1] 67a2e213e7e9, mm: cma: fix incorrect type conversion for size during dma allocation Link: https://lore.kernel.org/linux-mm/20210324043434.GP1719932@casper.infradead.org/ Link: https://lkml.kernel.org/r/20210331164018.710560-1-minchan@kernel.org Signed-off-by: Minchan Kim Reviewed-by: David Hildenbrand Cc: Matthew Wilcox Cc: David Hildenbrand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: cma: add the CMA instance name to cma trace events

2021-05-05T18:27:24+00:00

There were missing places to add cma instance name. To identify each CMA instance, let's add the name for every cma trace. This patch also changes the existing cma_trace_alloc to cma_trace_finish since we have cma_alloc_start[1]. [1] https://lore.kernel.org/linux-mm/20210324160740.15901-1-georgi.djakov@linaro.org Link: https://lkml.kernel.org/r/20210330220237.748899-1-minchan@kernel.org Signed-off-by: Minchan Kim Cc: Liam Mark Cc: Georgi Djakov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: cma: support sysfs

2021-05-05T18:27:24+00:00

Since CMA is getting used more widely, it's more important to keep monitoring CMA statistics for system health since it's directly related to user experience. This patch introduces sysfs statistics for CMA, in order to provide some basic monitoring of the CMA allocator. * the number of CMA page successful allocations * the number of CMA page allocation failures These two values allow the user to calcuate the allocation failure rate for each CMA area. e.g.) /sys/kernel/mm/cma/WIFI/alloc_pages_[success|fail] /sys/kernel/mm/cma/SENSOR/alloc_pages_[success|fail] /sys/kernel/mm/cma/BLUETOOTH/alloc_pages_[success|fail] The cma_stat was intentionally allocated by dynamic allocation to harmonize with kobject lifetime management. https://lore.kernel.org/linux-mm/YCOAmXqt6dZkCQYs@kroah.com/ Link: https://lkml.kernel.org/r/20210324230759.2213957-1-minchan@kernel.org Link: https://lore.kernel.org/linux-mm/20210316100433.17665-1-colin.king@canonical.com/ Signed-off-by: Minchan Kim Signed-off-by: Colin Ian King Tested-by: Dmitry Osipenko Reviewed-by: Dmitry Osipenko Reviewed-by: Greg Kroah-Hartman Reviewed-by: John Hubbard Tested-by: Anders Roxell Cc: Suren Baghdasaryan Cc: John Dias Cc: Matthew Wilcox (Oracle) Cc: Colin Ian King Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: cma: add trace events for CMA alloc perf testing

2021-05-05T18:27:24+00:00

Add cma and migrate trace events to enable CMA allocation performance to be measured via ftrace. [georgi.djakov@linaro.org: add the CMA instance name to the cma_alloc_start trace event] Link: https://lkml.kernel.org/r/20210326155414.25006-1-georgi.djakov@linaro.org Link: https://lkml.kernel.org/r/20210324160740.15901-1-georgi.djakov@linaro.org Signed-off-by: Liam Mark Signed-off-by: Georgi Djakov Acked-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: cma: use pr_err_ratelimited for CMA warning

2021-05-05T18:27:24+00:00

If we did not reserve extra CMA memory, the log buffer can be easily filled up by CMA failure warning when the devices calling dmam_alloc_coherent() to alloc DMA memory. Thus we can use pr_err_ratelimited() instead to reduce the duplicate CMA warning. Link: https://lkml.kernel.org/r/ce2251ef49e1727a9a40531d1996660b05462bd2.1615279825.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Reviewed-by: David Hildenbrand Acked-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds