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MEDIUM: fd: remove the FD_EV_POLLED status bit
Since commit 7ac0e35f2 in 1.9-dev1 ("MAJOR: fd: compute the new fd polling
state out of the fd lock") we've started to update the FD POLLED bit a
bit more aggressively. Lately with the removal of the FD cache, this bit
is always equal to the ACTIVE bit. There's no point continuing to watch
it and update it anymore, all it does is create confusion and complicate
the code. One interesting side effect is that it now becomes visible that
all fd_*_{send,recv}() operations systematically call updt_fd_polling(),
except fd_cant_recv()/fd_cant_send() which never saw it change.
This commit is contained in:
Willy Tarreau
parent
51bb185618
commit
5bee3e2f47
@ -1,4 +1,4 @@
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#FIG 3.2
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#FIG 3.2 Produced by xfig version 3.2.7a
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Portrait
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Center
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Metric
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@ -7,6 +7,17 @@ A4
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Single
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-2
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1200 2
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6 2520 990 4725 3645
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4 0 0 50 -1 16 10 0.0000 4 150 855 2520 1125 R=ready flag\001
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4 0 0 50 -1 16 10 0.0000 4 150 885 2520 1290 A=active flag\001
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4 0 0 50 -1 16 10 0.0000 4 150 1365 2520 2475 fd_want sets A flag\001
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4 0 0 50 -1 16 10 0.0000 4 150 1440 2520 2640 fd_stop clears A flag\001
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4 0 0 50 -1 16 10 0.0000 4 150 1995 2520 3465 fd_done does what's best to\001
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4 0 0 50 -1 16 10 0.0000 4 120 2025 2700 3630 minimize the amount of work.\001
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4 0 0 50 -1 16 10 0.0000 4 150 1905 2520 3300 update() updates the poller.\001
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4 0 0 50 -1 16 10 0.0000 4 150 2190 2520 2970 fd_cant clears R flag (EAGAIN)\001
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4 0 0 50 -1 16 10 0.0000 4 150 2115 2520 3135 fd_rdy sets R flag (poll return)\001
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-6
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
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1125 1350 1125 1800
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@ -16,99 +27,38 @@ Single
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
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1125 3150 1125 3600
|
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
|
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2925 3150 2925 3600
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
|
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2925 2250 2925 2700
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
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2925 1350 2925 1800
|
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
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1575 1800 1575 1350
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
|
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1575 3600 1575 3150
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
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3375 2700 3375 2250
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
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3375 1800 3375 1350
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
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2700 1125 1800 1125
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
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2700 3825 1800 3825
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2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
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3600 1350 2700 1350 2700 900 3600 900 3600 1350
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2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
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1800 1350 900 1350 900 900 1800 900 1800 1350
|
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2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
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1800 2250 900 2250 900 1800 1800 1800 1800 2250
|
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2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
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3600 2250 2700 2250 2700 1800 3600 1800 3600 2250
|
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2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
|
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3600 3150 2700 3150 2700 2700 3600 2700 3600 3150
|
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2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
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3600 4050 2700 4050 2700 3600 3600 3600 3600 4050
|
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2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
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1800 4050 900 4050 900 3600 1800 3600 1800 4050
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2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
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1800 3150 900 3150 900 2700 1800 2700 1800 3150
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
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1800 2925 2700 2925
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1350 450 1350 900
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2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
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1 1 1.00 90.00 180.00
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1350 450 1350 900
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4 1 0 50 -1 16 8 0.0000 4 120 330 2250 1080 update\001
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4 1 0 50 -1 16 8 0.0000 4 120 330 2250 3780 update\001
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4 2 0 50 -1 16 8 0.0000 4 75 240 2880 1485 want\001
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4 0 0 50 -1 16 8 0.0000 4 105 210 3420 1755 stop\001
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4 0 0 50 -1 16 8 0.0000 4 120 585 3420 2610 poll()=>rdy\001
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4 2 0 50 -1 16 8 0.0000 4 75 210 2835 2385 cant\001
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4 2 0 50 -1 16 8 0.0000 4 90 285 2835 2655 done*\001
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4 2 0 50 -1 16 8 0.0000 4 90 255 2835 2520 wait*\001
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4 2 0 50 -1 16 8 0.0000 4 75 240 1080 1485 want\001
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4 0 0 50 -1 16 8 0.0000 4 105 210 1665 1755 stop\001
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4 0 0 50 -1 16 8 0.0000 4 90 240 1665 1620 done\001
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4 2 0 50 -1 16 8 0.0000 4 75 210 1035 2385 cant\001
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4 2 0 50 -1 16 8 0.0000 4 90 255 1035 2520 wait*\001
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4 2 0 50 -1 16 8 0.0000 4 105 210 1035 3285 stop\001
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4 0 0 50 -1 16 8 0.0000 4 75 240 1665 3510 want\001
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4 2 0 50 -1 16 8 0.0000 4 105 210 2835 3285 stop\001
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4 1 0 50 -1 16 10 0.0000 4 105 735 1350 1080 STOPPED\001
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4 1 0 50 -1 16 10 0.0000 4 105 630 3150 1080 PAUSED\001
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4 1 0 50 -1 16 10 0.0000 4 105 555 1350 1980 ACTIVE\001
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4 1 0 50 -1 16 10 0.0000 4 105 525 3150 1980 READY\001
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4 1 0 50 -1 16 10 0.0000 4 105 825 1350 2880 MUSTPOLL\001
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4 1 0 50 -1 16 10 0.0000 4 105 615 3150 2880 POLLED\001
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4 1 0 50 -1 16 10 0.0000 4 105 765 1350 3780 DISABLED\001
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4 1 0 50 -1 16 10 0.0000 4 105 525 3150 3780 ABORT\001
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4 1 0 50 -1 16 8 0.0000 4 105 360 1350 1260 R,!A,!P\001
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4 1 0 50 -1 16 8 0.0000 4 105 330 1350 2160 R,A,!P\001
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4 1 0 50 -1 16 8 0.0000 4 105 330 3150 1260 R,!A,P\001
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4 1 0 50 -1 16 8 0.0000 4 105 300 3150 2160 R,A,P\001
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4 1 0 50 -1 16 8 0.0000 4 105 330 3150 3060 !R,A,P\001
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4 1 0 50 -1 16 8 0.0000 4 105 360 1350 3060 !R,A,!P\001
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4 1 0 50 -1 16 8 0.0000 4 105 390 1350 3960 !R,!A,!P\001
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4 1 0 50 -1 16 8 0.0000 4 105 360 3150 3960 !R,!A,P\001
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4 1 0 50 -1 16 8 0.0000 4 120 330 2250 2880 update\001
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4 0 0 50 -1 16 10 0.0000 4 135 885 4275 1125 R=ready flag\001
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4 0 0 50 -1 16 10 0.0000 4 135 900 4275 1290 A=active flag\001
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4 0 0 50 -1 16 10 0.0000 4 135 915 4275 1455 P=polled flag\001
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4 0 0 50 -1 16 10 0.0000 4 135 2250 4275 1785 Transitions marked with a star (*)\001
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4 0 0 50 -1 16 10 0.0000 4 135 2505 4275 1950 are only possible with level-triggered\001
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4 0 0 50 -1 16 10 0.0000 4 135 495 4275 2115 pollers.\001
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4 0 0 50 -1 16 10 0.0000 4 135 1335 4275 2475 fd_want sets A flag\001
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4 0 0 50 -1 16 10 0.0000 4 135 1425 4275 2640 fd_stop clears A flag\001
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4 0 0 50 -1 16 10 0.0000 4 135 2340 4275 2805 fd_wait clears R flag on LT pollers\001
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4 0 0 50 -1 16 10 0.0000 4 135 1980 4275 3465 fd_done does what's best to\001
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4 0 0 50 -1 16 10 0.0000 4 105 2010 4455 3630 minimize the amount of work.\001
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4 0 0 50 -1 16 10 0.0000 4 135 1935 4275 3300 update() updates the poller.\001
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4 0 0 50 -1 16 10 0.0000 4 135 2145 4275 2970 fd_cant clears R flag (EAGAIN)\001
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4 0 0 50 -1 16 10 0.0000 4 135 2040 4275 3135 fd_rdy sets R flag (poll return)\001
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1575 2700 1575 2250
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4 2 0 50 -1 16 8 0.0000 4 105 270 1080 1485 want\001
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4 2 0 50 -1 16 8 0.0000 4 120 255 1035 3285 stop\001
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4 0 0 50 -1 16 8 0.0000 4 105 270 1665 3510 want\001
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4 1 0 50 -1 16 10 0.0000 4 120 735 1350 1080 STOPPED\001
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4 1 0 50 -1 16 10 0.0000 4 120 795 1350 3780 DISABLED\001
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4 1 0 50 -1 16 10 0.0000 4 120 555 1350 2880 ACTIVE\001
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4 1 0 50 -1 16 10 0.0000 4 120 540 1350 1980 READY\001
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4 0 0 50 -1 16 8 0.0000 4 90 210 1665 2565 may\001
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4 2 0 50 -1 16 8 0.0000 4 105 240 1035 2430 cant\001
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4 1 0 50 -1 16 8 0.0000 4 120 240 1350 1260 R,!A\001
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4 1 0 50 -1 16 8 0.0000 4 120 210 1350 2160 R,A\001
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4 1 0 50 -1 16 8 0.0000 4 120 240 1350 3060 !R,A\001
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4 1 0 50 -1 16 8 0.0000 4 120 270 1350 3960 !R,!A\001
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4 0 0 50 -1 16 8 0.0000 4 120 255 1665 1710 stop\001
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4 2 0 50 -1 16 8 0.0000 4 105 285 1035 2610 done\001
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@ -268,20 +268,6 @@ static inline void __conn_xprt_stop_recv(struct connection *c)
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c->flags &= ~CO_FL_XPRT_RD_ENA;
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}
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/* this one is used only to stop speculative recv(). It doesn't stop it if the
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* fd is already polled in order to avoid expensive polling status changes.
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* Since it might require the upper layer to re-enable reading, we'll return 1
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* if we've really stopped something otherwise zero.
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*/
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static inline int __conn_xprt_done_recv(struct connection *c)
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{
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if (!conn_ctrl_ready(c) || !fd_recv_polled(c->handle.fd)) {
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c->flags &= ~CO_FL_XPRT_RD_ENA;
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return 1;
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}
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return 0;
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}
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static inline void __conn_xprt_want_send(struct connection *c)
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{
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c->flags |= CO_FL_XPRT_WR_ENA;
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@ -183,14 +183,6 @@ static inline int fd_recv_ready(const int fd)
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return (unsigned)fdtab[fd].state & FD_EV_READY_R;
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}
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/*
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* returns true if the FD is polled for recv
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*/
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static inline int fd_recv_polled(const int fd)
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{
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return (unsigned)fdtab[fd].state & FD_EV_POLLED_R;
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}
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/*
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* returns the FD's send state (FD_EV_*)
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*/
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@ -215,14 +207,6 @@ static inline int fd_send_ready(const int fd)
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return (unsigned)fdtab[fd].state & FD_EV_READY_W;
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}
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/*
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* returns true if the FD is polled for send
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*/
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static inline int fd_send_polled(const int fd)
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{
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return (unsigned)fdtab[fd].state & FD_EV_POLLED_W;
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}
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/*
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* returns true if the FD is active for recv or send
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*/
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@ -241,10 +225,7 @@ static inline void fd_stop_recv(int fd)
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if (!(old & FD_EV_ACTIVE_R))
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return;
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new = old & ~FD_EV_ACTIVE_R;
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new &= ~FD_EV_POLLED_R;
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} while (unlikely(!_HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
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if ((old ^ new) & FD_EV_POLLED_R)
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updt_fd_polling(fd);
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}
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@ -258,10 +239,7 @@ static inline void fd_stop_send(int fd)
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if (!(old & FD_EV_ACTIVE_W))
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return;
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new = old & ~FD_EV_ACTIVE_W;
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new &= ~FD_EV_POLLED_W;
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} while (unlikely(!_HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
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if ((old ^ new) & FD_EV_POLLED_W)
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updt_fd_polling(fd);
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}
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@ -275,10 +253,7 @@ static inline void fd_stop_both(int fd)
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if (!(old & FD_EV_ACTIVE_RW))
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return;
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new = old & ~FD_EV_ACTIVE_RW;
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new &= ~FD_EV_POLLED_RW;
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} while (unlikely(!_HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
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if ((old ^ new) & FD_EV_POLLED_RW)
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updt_fd_polling(fd);
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}
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@ -292,12 +267,7 @@ static inline void fd_cant_recv(const int fd)
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if (!(old & FD_EV_READY_R))
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return;
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new = old & ~FD_EV_READY_R;
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if (new & FD_EV_ACTIVE_R)
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new |= FD_EV_POLLED_R;
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} while (unlikely(!_HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
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if ((old ^ new) & FD_EV_POLLED_R)
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updt_fd_polling(fd);
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}
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/* Report that FD <fd> may receive again without polling. */
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@ -320,14 +290,10 @@ static inline void fd_done_recv(const int fd)
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old = fdtab[fd].state;
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do {
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if ((old & (FD_EV_POLLED_R|FD_EV_READY_R)) != (FD_EV_POLLED_R|FD_EV_READY_R))
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if ((old & (FD_EV_ACTIVE_R|FD_EV_READY_R)) != (FD_EV_ACTIVE_R|FD_EV_READY_R))
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return;
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new = old & ~FD_EV_READY_R;
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if (new & FD_EV_ACTIVE_R)
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new |= FD_EV_POLLED_R;
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} while (unlikely(!_HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
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if ((old ^ new) & FD_EV_POLLED_R)
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updt_fd_polling(fd);
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}
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@ -341,12 +307,7 @@ static inline void fd_cant_send(const int fd)
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if (!(old & FD_EV_READY_W))
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return;
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new = old & ~FD_EV_READY_W;
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if (new & FD_EV_ACTIVE_W)
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new |= FD_EV_POLLED_W;
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} while (unlikely(!_HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
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if ((old ^ new) & FD_EV_POLLED_W)
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updt_fd_polling(fd);
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}
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/* Report that FD <fd> may send again without polling (EAGAIN not detected). */
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@ -367,10 +328,8 @@ static inline void fd_want_recv(int fd)
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do {
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if (old & FD_EV_ACTIVE_R)
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return;
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new = old | FD_EV_ACTIVE_R | FD_EV_POLLED_R;
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new = old | FD_EV_ACTIVE_R;
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} while (unlikely(!_HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
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if ((old ^ new) & FD_EV_POLLED_R)
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updt_fd_polling(fd);
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}
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@ -383,10 +342,8 @@ static inline void fd_want_send(int fd)
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do {
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if (old & FD_EV_ACTIVE_W)
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return;
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new = old | FD_EV_ACTIVE_W | FD_EV_POLLED_W;
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new = old | FD_EV_ACTIVE_W;
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} while (unlikely(!_HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
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if ((old ^ new) & FD_EV_POLLED_W)
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updt_fd_polling(fd);
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}
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@ -47,22 +47,18 @@ enum {
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#define FD_POLL_DATA (FD_POLL_IN | FD_POLL_OUT)
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#define FD_POLL_STICKY (FD_POLL_ERR | FD_POLL_HUP)
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/* FD bits used for different polling states in each direction */
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#define FD_EV_ACTIVE 1U
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#define FD_EV_READY 2U
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#define FD_EV_POLLED 4U
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/* bits positions for a few flags */
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#define FD_EV_READY_R_BIT 1
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#define FD_EV_READY_W_BIT 5
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#define FD_EV_STATUS (FD_EV_ACTIVE | FD_EV_POLLED | FD_EV_READY)
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#define FD_EV_STATUS (FD_EV_ACTIVE | FD_EV_READY)
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#define FD_EV_STATUS_R (FD_EV_STATUS)
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#define FD_EV_STATUS_W (FD_EV_STATUS << 4)
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#define FD_EV_POLLED_R (FD_EV_POLLED)
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#define FD_EV_POLLED_W (FD_EV_POLLED << 4)
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#define FD_EV_POLLED_RW (FD_EV_POLLED_R | FD_EV_POLLED_W)
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#define FD_EV_ACTIVE_R (FD_EV_ACTIVE)
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#define FD_EV_ACTIVE_W (FD_EV_ACTIVE << 4)
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#define FD_EV_ACTIVE_RW (FD_EV_ACTIVE_R | FD_EV_ACTIVE_W)
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@ -71,17 +67,6 @@ enum {
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#define FD_EV_READY_W (FD_EV_READY << 4)
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#define FD_EV_READY_RW (FD_EV_READY_R | FD_EV_READY_W)
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enum fd_states {
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FD_ST_DISABLED = 0,
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FD_ST_MUSTPOLL,
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FD_ST_STOPPED,
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FD_ST_ACTIVE,
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FD_ST_ABORT,
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FD_ST_POLLED,
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FD_ST_PAUSED,
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FD_ST_READY
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};
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/* This is the value used to mark a file descriptor as dead. This value is
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* negative, this is important so that tests on fd < 0 properly match. It
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@ -1000,13 +1000,11 @@ static int cli_io_handler_show_fd(struct appctx *appctx)
|
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li = fdt.owner;
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chunk_printf(&trash,
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" %5d : st=0x%02x(R:%c%c%c W:%c%c%c) ev=0x%02x(%c%c%c%c%c) [%c%c] tmask=0x%lx umask=0x%lx owner=%p iocb=%p(%s)",
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||||
" %5d : st=0x%02x(R:%c%c W:%c%c) ev=0x%02x(%c%c%c%c%c) [%c%c] tmask=0x%lx umask=0x%lx owner=%p iocb=%p(%s)",
|
||||
fd,
|
||||
fdt.state,
|
||||
(fdt.state & FD_EV_POLLED_R) ? 'P' : 'p',
|
||||
(fdt.state & FD_EV_READY_R) ? 'R' : 'r',
|
||||
(fdt.state & FD_EV_ACTIVE_R) ? 'A' : 'a',
|
||||
(fdt.state & FD_EV_POLLED_W) ? 'P' : 'p',
|
||||
(fdt.state & FD_EV_READY_W) ? 'R' : 'r',
|
||||
(fdt.state & FD_EV_ACTIVE_W) ? 'A' : 'a',
|
||||
fdt.ev,
|
||||
|
||||
@ -69,7 +69,7 @@ static void _update_fd(int fd)
|
||||
en = fdtab[fd].state;
|
||||
|
||||
if ((polled_mask[fd].poll_send | polled_mask[fd].poll_recv) & tid_bit) {
|
||||
if (!(fdtab[fd].thread_mask & tid_bit) || !(en & FD_EV_POLLED_RW)) {
|
||||
if (!(fdtab[fd].thread_mask & tid_bit) || !(en & FD_EV_ACTIVE_RW)) {
|
||||
/* fd removed from poll list */
|
||||
opcode = EPOLL_CTL_DEL;
|
||||
if (polled_mask[fd].poll_recv & tid_bit)
|
||||
@ -78,19 +78,19 @@ static void _update_fd(int fd)
|
||||
_HA_ATOMIC_AND(&polled_mask[fd].poll_send, ~tid_bit);
|
||||
}
|
||||
else {
|
||||
if (((en & FD_EV_POLLED_R) != 0) ==
|
||||
if (((en & FD_EV_ACTIVE_R) != 0) ==
|
||||
((polled_mask[fd].poll_recv & tid_bit) != 0) &&
|
||||
((en & FD_EV_POLLED_W) != 0) ==
|
||||
((en & FD_EV_ACTIVE_W) != 0) ==
|
||||
((polled_mask[fd].poll_send & tid_bit) != 0))
|
||||
return;
|
||||
if (en & FD_EV_POLLED_R) {
|
||||
if (en & FD_EV_ACTIVE_R) {
|
||||
if (!(polled_mask[fd].poll_recv & tid_bit))
|
||||
_HA_ATOMIC_OR(&polled_mask[fd].poll_recv, tid_bit);
|
||||
} else {
|
||||
if (polled_mask[fd].poll_recv & tid_bit)
|
||||
_HA_ATOMIC_AND(&polled_mask[fd].poll_recv, ~tid_bit);
|
||||
}
|
||||
if (en & FD_EV_POLLED_W) {
|
||||
if (en & FD_EV_ACTIVE_W) {
|
||||
if (!(polled_mask[fd].poll_send & tid_bit))
|
||||
_HA_ATOMIC_OR(&polled_mask[fd].poll_send, tid_bit);
|
||||
} else {
|
||||
@ -101,12 +101,12 @@ static void _update_fd(int fd)
|
||||
opcode = EPOLL_CTL_MOD;
|
||||
}
|
||||
}
|
||||
else if ((fdtab[fd].thread_mask & tid_bit) && (en & FD_EV_POLLED_RW)) {
|
||||
else if ((fdtab[fd].thread_mask & tid_bit) && (en & FD_EV_ACTIVE_RW)) {
|
||||
/* new fd in the poll list */
|
||||
opcode = EPOLL_CTL_ADD;
|
||||
if (en & FD_EV_POLLED_R)
|
||||
if (en & FD_EV_ACTIVE_R)
|
||||
_HA_ATOMIC_OR(&polled_mask[fd].poll_recv, tid_bit);
|
||||
if (en & FD_EV_POLLED_W)
|
||||
if (en & FD_EV_ACTIVE_W)
|
||||
_HA_ATOMIC_OR(&polled_mask[fd].poll_send, tid_bit);
|
||||
}
|
||||
else {
|
||||
@ -115,10 +115,10 @@ static void _update_fd(int fd)
|
||||
|
||||
/* construct the epoll events based on new state */
|
||||
ev.events = 0;
|
||||
if (en & FD_EV_POLLED_R)
|
||||
if (en & FD_EV_ACTIVE_R)
|
||||
ev.events |= EPOLLIN | EPOLLRDHUP;
|
||||
|
||||
if (en & FD_EV_POLLED_W)
|
||||
if (en & FD_EV_ACTIVE_W)
|
||||
ev.events |= EPOLLOUT;
|
||||
|
||||
ev.data.fd = fd;
|
||||
|
||||
@ -46,9 +46,9 @@ static inline int evports_state_to_events(int state)
|
||||
{
|
||||
int events = 0;
|
||||
|
||||
if (state & FD_EV_POLLED_W)
|
||||
if (state & FD_EV_ACTIVE_W)
|
||||
events |= POLLOUT;
|
||||
if (state & FD_EV_POLLED_R)
|
||||
if (state & FD_EV_ACTIVE_R)
|
||||
events |= POLLIN;
|
||||
|
||||
return (events);
|
||||
@ -73,7 +73,7 @@ static void _update_fd(int fd)
|
||||
|
||||
en = fdtab[fd].state;
|
||||
|
||||
if (!(fdtab[fd].thread_mask & tid_bit) || !(en & FD_EV_POLLED_RW)) {
|
||||
if (!(fdtab[fd].thread_mask & tid_bit) || !(en & FD_EV_ACTIVE_RW)) {
|
||||
if (!(polled_mask[fd].poll_recv & tid_bit) &&
|
||||
!(polled_mask[fd].poll_send & tid_bit)) {
|
||||
/* fd was not watched, it's still not */
|
||||
@ -89,14 +89,14 @@ static void _update_fd(int fd)
|
||||
else {
|
||||
/* OK fd has to be monitored, it was either added or changed */
|
||||
events = evports_state_to_events(en);
|
||||
if (en & FD_EV_POLLED_R) {
|
||||
if (en & FD_EV_ACTIVE_R) {
|
||||
if (!(polled_mask[fd].poll_recv & tid_bit))
|
||||
_HA_ATOMIC_OR(&polled_mask[fd].poll_recv, tid_bit);
|
||||
} else {
|
||||
if (polled_mask[fd].poll_recv & tid_bit)
|
||||
_HA_ATOMIC_AND(&polled_mask[fd].poll_recv, ~tid_bit);
|
||||
}
|
||||
if (en & FD_EV_POLLED_W) {
|
||||
if (en & FD_EV_ACTIVE_W) {
|
||||
if (!(polled_mask[fd].poll_send & tid_bit))
|
||||
_HA_ATOMIC_OR(&polled_mask[fd].poll_send, tid_bit);
|
||||
} else {
|
||||
|
||||
@ -43,7 +43,7 @@ static int _update_fd(int fd, int start)
|
||||
|
||||
en = fdtab[fd].state;
|
||||
|
||||
if (!(fdtab[fd].thread_mask & tid_bit) || !(en & FD_EV_POLLED_RW)) {
|
||||
if (!(fdtab[fd].thread_mask & tid_bit) || !(en & FD_EV_ACTIVE_RW)) {
|
||||
if (!(polled_mask[fd].poll_recv & tid_bit) &&
|
||||
!(polled_mask[fd].poll_send & tid_bit)) {
|
||||
/* fd was not watched, it's still not */
|
||||
@ -60,7 +60,7 @@ static int _update_fd(int fd, int start)
|
||||
else {
|
||||
/* OK fd has to be monitored, it was either added or changed */
|
||||
|
||||
if (en & FD_EV_POLLED_R) {
|
||||
if (en & FD_EV_ACTIVE_R) {
|
||||
if (!(polled_mask[fd].poll_recv & tid_bit)) {
|
||||
EV_SET(&kev[changes++], fd, EVFILT_READ, EV_ADD, 0, 0, NULL);
|
||||
_HA_ATOMIC_OR(&polled_mask[fd].poll_recv, tid_bit);
|
||||
@ -71,7 +71,7 @@ static int _update_fd(int fd, int start)
|
||||
HA_ATOMIC_AND(&polled_mask[fd].poll_recv, ~tid_bit);
|
||||
}
|
||||
|
||||
if (en & FD_EV_POLLED_W) {
|
||||
if (en & FD_EV_ACTIVE_W) {
|
||||
if (!(polled_mask[fd].poll_send & tid_bit)) {
|
||||
EV_SET(&kev[changes++], fd, EVFILT_WRITE, EV_ADD, 0, 0, NULL);
|
||||
_HA_ATOMIC_OR(&polled_mask[fd].poll_send, tid_bit);
|
||||
|
||||
@ -57,7 +57,7 @@ static void _update_fd(int fd, int *max_add_fd)
|
||||
* don't check the tid_bit. First thread to see the update
|
||||
* takes it for every other one.
|
||||
*/
|
||||
if (!(en & FD_EV_POLLED_RW)) {
|
||||
if (!(en & FD_EV_ACTIVE_RW)) {
|
||||
if (!(polled_mask[fd].poll_recv | polled_mask[fd].poll_send)) {
|
||||
/* fd was not watched, it's still not */
|
||||
return;
|
||||
@ -70,7 +70,7 @@ static void _update_fd(int fd, int *max_add_fd)
|
||||
}
|
||||
else {
|
||||
/* OK fd has to be monitored, it was either added or changed */
|
||||
if (!(en & FD_EV_POLLED_R)) {
|
||||
if (!(en & FD_EV_ACTIVE_R)) {
|
||||
hap_fd_clr(fd, fd_evts[DIR_RD]);
|
||||
if (polled_mask[fd].poll_recv & tid_bit)
|
||||
_HA_ATOMIC_AND(&polled_mask[fd].poll_recv, ~tid_bit);
|
||||
@ -80,7 +80,7 @@ static void _update_fd(int fd, int *max_add_fd)
|
||||
_HA_ATOMIC_OR(&polled_mask[fd].poll_recv, tid_bit);
|
||||
}
|
||||
|
||||
if (!(en & FD_EV_POLLED_W)) {
|
||||
if (!(en & FD_EV_ACTIVE_W)) {
|
||||
hap_fd_clr(fd, fd_evts[DIR_WR]);
|
||||
if (polled_mask[fd].poll_send & tid_bit)
|
||||
_HA_ATOMIC_AND(&polled_mask[fd].poll_send, ~tid_bit);
|
||||
|
||||
@ -48,7 +48,7 @@ static void _update_fd(int fd, int *max_add_fd)
|
||||
* don't check the tid_bit. First thread to see the update
|
||||
* takes it for every other one.
|
||||
*/
|
||||
if (!(en & FD_EV_POLLED_RW)) {
|
||||
if (!(en & FD_EV_ACTIVE_RW)) {
|
||||
if (!(polled_mask[fd].poll_recv | polled_mask[fd].poll_send)) {
|
||||
/* fd was not watched, it's still not */
|
||||
return;
|
||||
@ -61,7 +61,7 @@ static void _update_fd(int fd, int *max_add_fd)
|
||||
}
|
||||
else {
|
||||
/* OK fd has to be monitored, it was either added or changed */
|
||||
if (!(en & FD_EV_POLLED_R)) {
|
||||
if (!(en & FD_EV_ACTIVE_R)) {
|
||||
hap_fd_clr(fd, fd_evts[DIR_RD]);
|
||||
if (polled_mask[fd].poll_recv & tid_bit)
|
||||
_HA_ATOMIC_AND(&polled_mask[fd].poll_recv, ~tid_bit);
|
||||
@ -71,7 +71,7 @@ static void _update_fd(int fd, int *max_add_fd)
|
||||
_HA_ATOMIC_OR(&polled_mask[fd].poll_recv, tid_bit);
|
||||
}
|
||||
|
||||
if (!(en & FD_EV_POLLED_W)) {
|
||||
if (!(en & FD_EV_ACTIVE_W)) {
|
||||
hap_fd_clr(fd, fd_evts[DIR_WR]);
|
||||
if (polled_mask[fd].poll_send & tid_bit)
|
||||
_HA_ATOMIC_AND(&polled_mask[fd].poll_send, ~tid_bit);
|
||||
|
||||
98
src/fd.c
98
src/fd.c
@ -14,90 +14,64 @@
|
||||
* be considered even if its changes are reverted in the middle or if the fd is
|
||||
* replaced.
|
||||
*
|
||||
* It is important to understand that as long as all expected events are
|
||||
* processed, they might starve the polled events, especially because polled
|
||||
* I/O starvation quickly induces more cached I/O. One solution to this
|
||||
* consists in only processing a part of the events at once, but one drawback
|
||||
* is that unhandled events will still wake the poller up. Using an edge-
|
||||
* triggered poller such as EPOLL_ET will solve this issue though.
|
||||
*
|
||||
* The event state for an FD, as found in fdtab[].state, is maintained for each
|
||||
* direction. The state field is built this way, with R bits in the low nibble
|
||||
* and W bits in the high nibble for ease of access and debugging :
|
||||
*
|
||||
* 7 6 5 4 3 2 1 0
|
||||
* [ 0 | PW | RW | AW | 0 | PR | RR | AR ]
|
||||
* [ 0 | 0 | RW | AW | 0 | 0 | RR | AR ]
|
||||
*
|
||||
* A* = active *R = read
|
||||
* P* = polled *W = write
|
||||
* R* = ready
|
||||
* R* = ready *W = write
|
||||
*
|
||||
* An FD is marked "active" when there is a desire to use it.
|
||||
* An FD is marked "polled" when it is registered in the polling.
|
||||
* An FD is marked "ready" when it has not faced a new EAGAIN since last wake-up
|
||||
* (it is a cache of the last EAGAIN regardless of polling changes).
|
||||
* (it is a cache of the last EAGAIN regardless of polling changes). Each poller
|
||||
* has its own "polled" state for the same fd, as stored in the polled_mask.
|
||||
*
|
||||
* We have 8 possible states for each direction based on these 3 flags :
|
||||
* We have 4 possible states for each direction based on these 2 flags :
|
||||
*
|
||||
* +---+---+---+----------+---------------------------------------------+
|
||||
* | P | R | A | State | Description |
|
||||
* +---+---+---+----------+---------------------------------------------+
|
||||
* | 0 | 0 | 0 | DISABLED | No activity desired, not ready. |
|
||||
* | 0 | 0 | 1 | MUSTPOLL | Activity desired via polling. |
|
||||
* | 0 | 1 | 0 | STOPPED | End of activity without polling. |
|
||||
* | 0 | 1 | 1 | ACTIVE | Activity desired without polling. |
|
||||
* | 1 | 0 | 0 | ABORT | Aborted poll(). Not frequently seen. |
|
||||
* | 1 | 0 | 1 | POLLED | FD is being polled. |
|
||||
* | 1 | 1 | 0 | PAUSED | FD was paused while ready (eg: buffer full) |
|
||||
* | 1 | 1 | 1 | READY | FD was marked ready by poll() |
|
||||
* +---+---+---+----------+---------------------------------------------+
|
||||
* +---+---+----------+---------------------------------------------+
|
||||
* | R | A | State | Description |
|
||||
* +---+---+----------+---------------------------------------------+
|
||||
* | 0 | 0 | DISABLED | No activity desired, not ready. |
|
||||
* | 0 | 1 | ACTIVE | Activity desired. |
|
||||
* | 1 | 0 | STOPPED | End of activity. |
|
||||
* | 1 | 1 | READY | Activity desired and reported. |
|
||||
* +---+---+----------+---------------------------------------------+
|
||||
*
|
||||
* The transitions are pretty simple :
|
||||
* - fd_want_*() : set flag A
|
||||
* - fd_stop_*() : clear flag A
|
||||
* - fd_cant_*() : clear flag R (when facing EAGAIN)
|
||||
* - fd_may_*() : set flag R (upon return from poll())
|
||||
* - sync() : if (A) { if (!R) P := 1 } else { P := 0 }
|
||||
*
|
||||
* The PAUSED, ABORT and MUSTPOLL states are transient for level-trigerred
|
||||
* pollers and are fixed by the sync() which happens at the beginning of the
|
||||
* poller. For event-triggered pollers, only the MUSTPOLL state will be
|
||||
* transient and ABORT will lead to PAUSED. The ACTIVE state is the only stable
|
||||
* one which has P != A.
|
||||
* Each poller then computes its own polled state :
|
||||
* if (A) { if (!R) P := 1 } else { P := 0 }
|
||||
*
|
||||
* The READY state is a bit special as activity on the FD might be notified
|
||||
* both by the poller or by the cache. But it is needed for some multi-layer
|
||||
* protocols (eg: SSL) where connection activity is not 100% linked to FD
|
||||
* activity. Also some pollers might prefer to implement it as ACTIVE if
|
||||
* enabling/disabling the FD is cheap. The READY and ACTIVE states are the
|
||||
* two states for which a cache entry is allocated.
|
||||
* The state transitions look like the diagram below.
|
||||
*
|
||||
* The state transitions look like the diagram below. Only the 4 right states
|
||||
* have polling enabled :
|
||||
*
|
||||
* (POLLED=0) (POLLED=1)
|
||||
*
|
||||
* +----------+ sync +-------+
|
||||
* | DISABLED | <----- | ABORT | (READY=0, ACTIVE=0)
|
||||
* +----------+ +-------+
|
||||
* clr | ^ set | ^
|
||||
* | | | |
|
||||
* v | set v | clr
|
||||
* +----------+ sync +--------+
|
||||
* | MUSTPOLL | -----> | POLLED | (READY=0, ACTIVE=1)
|
||||
* +----------+ +--------+
|
||||
* ^ poll | ^
|
||||
* may +----------+
|
||||
* ,----| DISABLED | (READY=0, ACTIVE=0)
|
||||
* | +----------+
|
||||
* | want | ^
|
||||
* | | |
|
||||
* | EAGAIN v | EAGAIN
|
||||
* +--------+ +-------+
|
||||
* | ACTIVE | | READY | (READY=1, ACTIVE=1)
|
||||
* +--------+ +-------+
|
||||
* clr | ^ set | ^
|
||||
* | | | |
|
||||
* v | set v | clr
|
||||
* +---------+ sync +--------+
|
||||
* | STOPPED | <------ | PAUSED | (READY=1, ACTIVE=0)
|
||||
* +---------+ +--------+
|
||||
* | v | stop
|
||||
* | +----------+
|
||||
* | | ACTIVE | (READY=0, ACTIVE=1)
|
||||
* | +----------+
|
||||
* | | ^
|
||||
* | may | |
|
||||
* | v | EAGAIN (cant)
|
||||
* | +--------+
|
||||
* | | READY | (READY=1, ACTIVE=1)
|
||||
* | +--------+
|
||||
* | stop | ^
|
||||
* | | |
|
||||
* | v | want
|
||||
* | +---------+
|
||||
* `--->| STOPPED | (READY=1, ACTIVE=0)
|
||||
* +---------+
|
||||
*/
|
||||
|
||||
#include <stdio.h>
|
||||
|
||||
Loading…
Reference in New Issue
Block a user