Messages in this thread | | | Subject | Re: [PATCH v3 0/5] optimize memblock_next_valid_pfn and early_pfn_valid | From | Jia He <> | Date | Tue, 27 Mar 2018 15:15:08 +0800 |
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On 3/27/2018 9:02 AM, Wei Yang Wrote: > On Sun, Mar 25, 2018 at 08:02:14PM -0700, Jia He wrote: >> Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns >> where possible") tried to optimize the loop in memmap_init_zone(). But >> there is still some room for improvement. >> >> Patch 1 remain the memblock_next_valid_pfn when CONFIG_HAVE_ARCH_PFN_VALID >> is enabled >> Patch 2 optimizes the memblock_next_valid_pfn() >> Patch 3~5 optimizes the early_pfn_valid(), I have to split it into parts >> because the changes are located across subsystems. >> >> I tested the pfn loop process in memmap_init(), the same as before. >> As for the performance improvement, after this set, I can see the time >> overhead of memmap_init() is reduced from 41313 us to 24345 us in my >> armv8a server(QDF2400 with 96G memory). >> >> Attached the memblock region information in my server. >> [ 86.956758] Zone ranges: >> [ 86.959452] DMA [mem 0x0000000000200000-0x00000000ffffffff] >> [ 86.966041] Normal [mem 0x0000000100000000-0x00000017ffffffff] >> [ 86.972631] Movable zone start for each node >> [ 86.977179] Early memory node ranges >> [ 86.980985] node 0: [mem 0x0000000000200000-0x000000000021ffff] >> [ 86.987666] node 0: [mem 0x0000000000820000-0x000000000307ffff] >> [ 86.994348] node 0: [mem 0x0000000003080000-0x000000000308ffff] >> [ 87.001029] node 0: [mem 0x0000000003090000-0x00000000031fffff] >> [ 87.007710] node 0: [mem 0x0000000003200000-0x00000000033fffff] >> [ 87.014392] node 0: [mem 0x0000000003410000-0x000000000563ffff] >> [ 87.021073] node 0: [mem 0x0000000005640000-0x000000000567ffff] >> [ 87.027754] node 0: [mem 0x0000000005680000-0x00000000056dffff] >> [ 87.034435] node 0: [mem 0x00000000056e0000-0x00000000086fffff] >> [ 87.041117] node 0: [mem 0x0000000008700000-0x000000000871ffff] >> [ 87.047798] node 0: [mem 0x0000000008720000-0x000000000894ffff] >> [ 87.054479] node 0: [mem 0x0000000008950000-0x0000000008baffff] >> [ 87.061161] node 0: [mem 0x0000000008bb0000-0x0000000008bcffff] >> [ 87.067842] node 0: [mem 0x0000000008bd0000-0x0000000008c4ffff] >> [ 87.074524] node 0: [mem 0x0000000008c50000-0x0000000008e2ffff] >> [ 87.081205] node 0: [mem 0x0000000008e30000-0x0000000008e4ffff] >> [ 87.087886] node 0: [mem 0x0000000008e50000-0x0000000008fcffff] >> [ 87.094568] node 0: [mem 0x0000000008fd0000-0x000000000910ffff] >> [ 87.101249] node 0: [mem 0x0000000009110000-0x00000000092effff] >> [ 87.107930] node 0: [mem 0x00000000092f0000-0x000000000930ffff] >> [ 87.114612] node 0: [mem 0x0000000009310000-0x000000000963ffff] >> [ 87.121293] node 0: [mem 0x0000000009640000-0x000000000e61ffff] >> [ 87.127975] node 0: [mem 0x000000000e620000-0x000000000e64ffff] >> [ 87.134657] node 0: [mem 0x000000000e650000-0x000000000fffffff] >> [ 87.141338] node 0: [mem 0x0000000010800000-0x0000000017feffff] >> [ 87.148019] node 0: [mem 0x000000001c000000-0x000000001c00ffff] >> [ 87.154701] node 0: [mem 0x000000001c010000-0x000000001c7fffff] >> [ 87.161383] node 0: [mem 0x000000001c810000-0x000000007efbffff] >> [ 87.168064] node 0: [mem 0x000000007efc0000-0x000000007efdffff] >> [ 87.174746] node 0: [mem 0x000000007efe0000-0x000000007efeffff] >> [ 87.181427] node 0: [mem 0x000000007eff0000-0x000000007effffff] >> [ 87.188108] node 0: [mem 0x000000007f000000-0x00000017ffffffff] > Hi, Jia > > I haven't taken a deep look into your code, just one curious question on your > memory layout. > > The log above is printed out in free_area_init_nodes(), which iterates on > memblock.memory and prints them. If I am not wrong, memory regions added to > memblock.memory are ordered and merged if possible. > > While from your log, I see many regions could be merged but are isolated. For > example, the last two region: > > node 0: [mem 0x000000007eff0000-0x000000007effffff] > node 0: [mem 0x000000007f000000-0x00000017ffffffff] > > So I am curious why they are isolated instead of combined to one. > > >From the code, the possible reason is the region's flag differs from each > other. If you have time, would you mind taking a look into this? > Hi Wei I thought these 2 have different flags [ 0.000000] idx=30,region [7eff0000:10000]flag=4 <--- aka MEMBLOCK_NOMAP [ 0.000000] node 0: [mem 0x000000007eff0000-0x000000007effffff] [ 0.000000] idx=31,region [7f000000:81000000]flag=0 <--- aka MEMBLOCK_NONE [ 0.000000] node 0: [mem 0x000000007f000000-0x00000017ffffffff]
-- Cheers, Jia
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