Take a look at the list of major contributors to the kernel, just covering top 50 between v5.0 and v5.3: $ git log v5.3...v5.0 | grep "^Author:" | cut -d"@"

Take a look at the list of major contributors to the kernel, just covering top 50 between v5.0 and v5.3: $ git log v5.3...v5.0 | grep "^Author:" | cut -d"@" -f2 | sed 's/>//' | sort | uniq -c | sort -n | tail -50 167 samsung.com 188 sang-engineering.com 190 acm.org 192 broadcom.com 196 collabora.com 206 ingics.com 207 infradead.org 207 lixom.net 219 pengutronix.de 223 glider.be 232 c-s.fr 232 microchip.com 247 mediatek.com 251 roeck-us.net 329 st.com 341 fb.com 341 socionext.com 346 netronome.com 360 ti.com 380 canonical.com 384 linuxfoundation.org 387 nvidia.com 388 codeaurora.org 398 arndb.de 424 embeddedor.com 460 renesas.com 469 chris-wilson.co.uk 498 baylibre.com 504 suse.com 516 chromium.org 539 suse.de 540 lst.de 554 oracle.com 652 nxp.com 682 bootlin.com 690 davemloft.net 697 linutronix.de 774 arm.com 781 linux.ibm.com 948 google.com 1052 linaro.org 1230 huawei.com 1315 mellanox.com 1333 linux-foundation.org 1477 linux.intel.com 1501 kernel.org 1851 amd.com 2229 redhat.com 2548 intel.com 4373 gmail.com There's the usual suspects in there (after a quick double check, it turns out microsoft.com just missed the cut-off with 140 commits, plus 2 from linux.microsoft.com, Amazon has authored 71, and alibaba have 139) No one wants to maintain out-of-tree patches, it's a complete pain. Google was doing it extensively with the Android project for the longest time, but they've been working hard at getting those all in to upstream to drastically reduce the work involved in updating the Android kernel.