linux/include
Linus Torvalds a28c8b9db8 pipe: remove 'waiting_writers' merging logic
This code is ancient, and goes back to when we only had a single page
for the pipe buffers.  The exact history is hidden in the mists of time
(ie "before git", and in fact predates the BK repository too).

At that long-ago point in time, it actually helped to try to merge big
back-and-forth pipe reads and writes, and not limit pipe reads to the
single pipe buffer in length just because that was all we had at a time.

However, since then we've expanded the pipe buffers to multiple pages,
and this logic really doesn't seem to make sense.  And a lot of it is
somewhat questionable (ie "hmm, the user asked for a non-blocking read,
but we see that there's a writer pending, so let's wait anyway to get
the extra data that the writer will have").

But more importantly, it makes the "go to sleep" logic much less
obvious, and considering the wakeup issues we've had, I want to make for
less of those kinds of things.

Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-07 13:21:01 -08:00
..
acpi Merge branches 'acpi-utils', 'acpi-platform', 'acpi-video' and 'acpi-doc' 2019-11-26 10:30:49 +01:00
asm-generic powerpc updates for 5.5 #2 2019-12-06 13:36:31 -08:00
clocksource x86/hyperv: Initialize clockevents earlier in CPU onlining 2019-11-15 10:33:49 +01:00
crypto crypto: ablkcipher - remove deprecated and unused ablkcipher support 2019-11-17 09:02:49 +08:00
drm mm + drm coherent memory support for vmwgfx 2019-11-30 09:38:11 -08:00
dt-bindings ARM: Device-tree updates 2019-12-05 12:09:47 -08:00
keys powerpc updates for 5.5 2019-11-30 14:35:43 -08:00
kunit
kvm Merge remote-tracking branch 'kvmarm/misc-5.5' into kvmarm/next 2019-11-08 11:27:29 +00:00
linux pipe: remove 'waiting_writers' merging logic 2019-12-07 13:21:01 -08:00
math-emu
media drm main pull for 5.5-rc1 2019-11-27 17:45:48 -08:00
misc
net net/tls: use sg_next() to walk sg entries 2019-11-28 22:40:29 -08:00
pcmcia
ras
rdma hmm related patches for 5.5 2019-11-30 10:33:14 -08:00
scsi scsi: target: iscsi: Wait for all commands to finish before freeing a session 2019-11-19 21:37:35 -05:00
soc drm msm + fixes for 5.5-rc1 2019-12-06 10:28:09 -08:00
sound ALSA: hda: Modify stream stripe mask only when needed 2019-12-03 07:46:30 +01:00
target
trace Two fixes and one patch that was missed: 2019-12-04 19:13:52 -08:00
uapi for-linus-20191205 2019-12-06 10:08:59 -08:00
vdso
video
xen dma-mapping updates for 5.5-rc1 2019-11-28 11:16:43 -08:00