linux_dsm_epyc7002/include
Linus Torvalds 2e00266297 Merge branch 'fs-file-descriptor-optimization'
Merge file descriptor allocation speedup.

Eric Dumazet has a test-case for a fairly common network deamon load
pattern: openign and closing a lot of sockets that each have very little
work done on them.  It turns out that in that case, the cost of just
finding the correct file descriptor number can be a dominating factor.

We've long had a trivial optimization for allocating file descriptors
sequentially, but that optimization ends up being not very effective
when other file descriptors are being closed concurrently, and the fd
patterns are not some simple FIFO pattern.  In such cases we ended up
spending a lot of time just scanning the bitmap of open file descriptors
in order to find the next file descriptor number to open.

This trivial patch-series mitigates that by simply introducing a
second-level bitmap of which words in the first bitmap are already fully
allocated.  That cuts down the cost of scanning by an order of magnitude
in some pathological (but realistic) cases.

The second patch is an even more trivial patch to avoid unnecessarily
dirtying the cacheline for the close-on-exec bit array that normally
ends up being all empty.

* fs-file-descriptor-optimization:
  vfs: conditionally clear close-on-exec flag
  vfs: Fix pathological performance case for __alloc_fd()
2015-11-01 16:43:24 -08:00
..
acpi ACPI: Eliminate CONFIG_.*{, _MODULE} #ifdef in favor of IS_ENABLED() 2015-09-15 03:05:45 +02:00
asm-generic Merge branch 'strscpy' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile 2015-10-04 16:31:13 +01:00
clocksource
crypto Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2015-09-08 12:41:25 -07:00
drm drm/dp/mst: make mst i2c transfer code more robust. 2015-10-15 09:06:20 +10:00
dt-bindings Merge branch 'drivers/reset' into next/late 2015-09-09 15:42:45 -07:00
keys
kvm arm/arm64: KVM: Remove 'config KVM_ARM_MAX_VCPUS' 2015-09-17 13:13:27 +01:00
linux Merge branch 'fs-file-descriptor-optimization' 2015-11-01 16:43:24 -08:00
math-emu
media media updates for v4.3-rc1 2015-09-11 16:42:39 -07:00
memory
misc
net openvswitch: Fix egress tunnel info. 2015-10-22 19:39:25 -07:00
pcmcia
ras
rdma Changes for 4.3-rc1 2015-09-19 20:04:11 -07:00
rxrpc
scsi Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2015-09-11 19:00:42 -07:00
soc IOMMU Updates for Linux v4.3 2015-09-08 17:22:35 -07:00
sound Merge remote-tracking branches 'asoc/fix/rt298', 'asoc/fix/sx', 'asoc/fix/wm8904' and 'asoc/fix/wm8962' into asoc-linus 2015-10-23 08:44:14 +09:00
target target: Propigate backend read-only to core_tpg_add_lun 2015-09-24 23:17:21 -07:00
trace Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2015-09-11 16:13:47 -07:00
uapi openvswitch: Clarify conntrack COMMIT behaviour 2015-10-21 19:33:38 -07:00
video libnvdimm for 4.3: 2015-09-08 14:35:59 -07:00
xen x86/xen: Support kexec/kdump in HVM guests by doing a soft reset 2015-09-28 14:48:52 +01:00
Kbuild