the lru is there to track least recently used messages so
we can evict them from the cache and refetch them again on
demand. for pop3 mailbox, which doesnt provide fetch routine,
the messages should never be put on the freelist.
The previous attempt to fix this problem (see changesets b32199e0f90a
and 00ae79a6ba50) caused all calls to cachefree to free the cached
message contents in addition to updating the LRU list. This causes
problems for the POP3 driver since it provides no fetch function; once
a message is evicted from the LRU cache, its contents is lost.
This time we fix cachefree to always update the LRU list but only free
the cached message contents if the driver provides a fetch function or
the force flag is set.
Some SD card readers are slow to unstall. We try to unstall them
in a loop if there's no SD card in there, but they're not stalled.
They're happily reporting that there's no SD card in them by giving
back the appropriate error code.
Skipping the unstall speeds up the retry loop, cutting the time spent
attaching the USB device at boot from multiple minutes to nearly instant.
Force the cacheclear operation in the LRU cache trimming loop in order
to guarantee that the cache becomes smaller with each iteration.
Without the force flag cacheclear is a no-op for mailboxes that do not
provide a fetch function, e.g. POP3.
because a client might not handle resize, rio would try to move ther
window offsceen after 750 ms. however, it does this by window name,
which could have been reassigned by another concurrent rio, causing the
wrong window to disappear.
now we always move the window offscreen before freeimage(). this way we
are sure to still have the right reference to the original window.
segclock() has to be called from hzclock(), otherwise
only processes running on cpu0 would catche the interrupt
and the time delta would be wrong.
lock the segment when allocating Seg->profile as
profile ctl might be issued from multiple processes.
Proc->debug qlock is not sufficient.
Seg->profile can never be freed or reallocated once
set as the timer interrupt accesses it without any
locking.
to read the value of the stack pointer register, snap
used Machdata->szreg to determine the width of the
SP register in the Ureg structure. however, the value
does not match the Ureg.sp type for a number of architectures
(mips2, amd64) and it is unclear if this was an oversight
as it is rarely used (snap is indeed the only user) or
if it was intended for a different purpose.
so we use szaddr instead which matches the stack pointer
width in the Ureg and fixes the truncated stack issue on
amd64.
this can happen when the on the final sync when the mailbox
is being freed:
freembox -> mboxdecref -> syncmbox -> wridxfile -> pridx -> insurecache -> msgincref
syncmbox() used to enter the mailbox into the hash tree to
update the qid.vers. this is wrong when we are doing the final
sync before freeing the mailbox as the hash reference has already
been removed by freemailbox().
also avoid adding hash entries for mails for the about to be
freed mailbox in cachehash().
add function to check the refcounts for Mailbox and Message on a fid
use the full 64 bit of the qid.path, so we can use the full 32 bit for the id
instead of only maintaining refcount for the top message, msgincref() now
adds a reference to all its parent messages including self and top message.
then we can check in recursive delmessage() that all the parts have a zero
refcount.
remove the Fid.mtop field, it was never used.
make sure deletion and flag changes only affect the top message.
cachefree(): only look for top message in lru. sub-parts are never
added to the cache.
use the nparts field when reading sub-part of existing message, so
that we parse the index right in case the number of parts somehow
changed.
messages marked as Deleted but still in inbox should be written
to the index.
instead of having application processors spin in mpshutdown()
with mmu on, and be subject to reboot() overriding kernel text
and modifying page tables, park the application processors in
rebootcode idle loop with the mmu off.
to reproduce:
u8int x, y;
x = 0xff;
y = 0xc0;
if((s8int)(x & y) >= 0)
print("help\n");
compiles correctly but prints a warning
warning: test.c:11 useless or misleading comparison: UINT >= 0
the issue is that compar() unconditionally skipped over
all left casts ignoring the case when a cast would sign
extend the value.
the new code only skips over the cast when the original
type with is smaller than the cast result or when they
are equal width and types have same signedness. so the
effective left hand side type is the last truncation
or sign extension.
to get $"1 right, remove Xqdol() and instead implement it in
terms of Xdol() instruction and use the new Xqw() instruction
to quote the resulting list.
a deadlock has been observed with samterm (thanks burnzez),
that shows the mouse ioproc being stuck in sending on the
resize channel, while the mouse consumer is stuck in a
readmouse() loop wanting a rectangle to be drawn by the
user:
recv(v=0x42df50)+0x28 /sys/src/libthread/channel.c:321
readmouse(mc=0x42df50)+0x54 /sys/src/libdraw/mouse.c:34
getrect(.ret=0x41bce0,but=0x4,mc=0x42df50)+0x62 /sys/src/libdraw/getrect.c:49
r=0x41bc70
rc=0x41bc70
getr(rp=0x41bce0)+0x24 /sys/src/cmd/samterm/main.c:244
p=0x6b000004f6
r=0x2
sweeptext(new=0x0,tag=0x2d)+0x12 /sys/src/cmd/samterm/menu.c:208
r=0x2
t=0x42df50
inmesg(type=0x2,count=0x2)+0x1ab /sys/src/cmd/samterm/mesg.c:136
m=0x10000002d
l=0x2d00001b00
i=0x43829000000001
t=0x438290
lp=0x42e050
rcv()+0x7a /sys/src/cmd/samterm/mesg.c:77
threadmain(argv=0x7ffffeffef90)+0x173 /sys/src/cmd/samterm/main.c:63
so avoid blocking in the mouse ioproc by using nbsend()
instead of send() for writing to the resize channel.
linux will send small, unpadded arp packets which may arrive over
wifi, so allow small packets into the bridge and pad any packets that
are too small when going out.
touchscreens signal multiple contact points (X/Y) in
the hid descriptor separated by being nested in separate
collections. the contact point is identified by a
optional contact id. if omited, we use the collection
index and report id.
so we collect all the items (X/Y, buttons, wheel) from
separate collections in Hidslot structures and in the
end combine all the slots together.
buttons are or'ed together while absolute X/Y is applied
when it changed. relative X/Y deltas get added together.
thanks to kivik and Glats for testing.
