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Revert "OPTIM: mux-h2: make h2_send() report more accurate wake up conditions"

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This reverts commit 9fbc01710a.

In 3.1-dev10, commit 9fbc01710a ("OPTIM: mux-h2: make h2_send() report
more accurate wake up conditions") leveraged the more accurate distinction
between demux and recv to decide when to wake the tasklet up after a send.
But other cases are needed. When we just need to wake the processing task
up so that it itself wakes up other streams, for example because these ones
are blocked. Indeed, a temporarily blocked stream may block other ones,
which will never be woken up if the demux has nothing to do.

In an ideal world we would check all cases where blocking flags were
dropped. However it looks like this case after a send is probably the
only one that deserves waking up the connection again. It's likely that
in practice the MUX_MFULL flag was dropped and that it was that one that
was blocking the send.

In addition, dealing with these cases was not sufficient, as one case was
encountered where dbuf was empty, subs=0, short_read still present while
in FRH state... and the timeouts were still there (easily found with
halog -tcn cD at a rate of 1-2 every 2 minutes roughly).

Interestingly, in a dump, some MBUF_HAS_DATA were seen on an empty mbuf,
so it means that certain conditions must be taken very carefully in the
wakeup conditions.

So overall this indicates that there remain subtle inconsistencies that
this optimization is sensitive to. It may have to be revisited later but
for now better revert it.

No backport is needed.

Annex:
  - first dump showing a dependency on WAIT_INLIST after h2_send():

    0x6dc2800: [23/Oct/2024:18:07:22.861247] id=1696 proto=tcpv4
      flags=0x100c4a, conn_retries=0, conn_exp=<NEVER> conn_et=0x000 srv_conn=0x597a900, pend_pos=(nil) waiting=0 epoch=0
      frontend=public (id=2 mode=http), listener=SSL (id=5)
      backend=gitweb-haproxy (id=6 mode=http)
      task=0x6e1d090 (state=0x00 nice=0 calls=23 rate=0 exp=2s tid=0(1/0) age=57s)
      txn=0x6e3f7c0 flags=0x43000 meth=1 status=200 req.st=MSG_DONE rsp.st=MSG_DATA req.f=0x4c rsp.f=0x2e
      scf=0x6dc33a0 flags=0x00002482 ioto=1m state=EST endp=CONN,0x6dc6c20,0x40405001 sub=3 rex=<NEVER> wex=3s rto=3s wto=3s
        iobuf.flags=0x00000000 .pipe=0 .buf=0@(nil)+0/0
          h2s=0x6dc6c20 h2s.id=59 .st=HCR .flg=0x7001 .rxwin=32712 .rxbuf.c=0 .t=0@(nil)+0/0 .h=0@(nil)+0/0
           .sc=0x6dc33a0(.flg=0x00002482 .app=0x6dc2800) .sd=0x6e83fd0(.flg=0x40405001)
           .subs=0x6dc33b8(ev=3 tl=0x6e22a20 tl.calls=10 tl.ctx=0x6dc33a0 tl.fct=sc_conn_io_cb)
           h2c=0x6e66570 h2c.st0=FRH .err=0 .maxid=77 .lastid=-1 .flg=0x2000e00 .nbst=2 .nbsc=2 .nbrcv=0 .glitches=0
           .fctl_cnt=0 .send_cnt=2 .tree_cnt=2 .orph_cnt=0 .sub=1 .dsi=77 .dbuf=0@(nil)+0/0
           .mbuf=[4..4|32],h=[0@(nil)+0/0],t=[0@(nil)+0/0] .task=0x6dbdc60 .exp=<NEVER>
          co0=0x7f84881614b0 ctrl=tcpv4 xprt=SSL mux=H2 data=STRM target=LISTENER:0x2acb7c0
          flags=0x80000300 fd=19 fd.state=121 updt=0 fd.tmask=0x1
      scb=0x2a8da90 flags=0x00001211 ioto=1m state=EST endp=CONN,0x6e5a530,0x106c0001 sub=0 rex=<NEVER> wex=<NEVER> rto=3s wto=<NEVER>
        iobuf.flags=0x00000000 .pipe=0 .buf=0@(nil)+0/0
          h1s=0x6e5a530 h1s.flg=0x14094 .sd.flg=0x106c0001 .req.state=MSG_DONE .res.state=MSG_DATA
           .meth=GET status=200 .sd.flg=0x106c0001 .sc.flg=0x00001211 .sc.app=0x6dc2800 .subs=(nil)
           h1c=0x7f84880f5f40 h1c.flg=0x80000020 .sub=0 .ibuf=32704@0x6ddef30+16262/32768 .obuf=0@(nil)+0/0 .task=0x6e131d0 .exp=<NEVER>
          co1=0x7f8488172b70 ctrl=tcpv4 xprt=RAW mux=H1 data=STRM target=SERVER:0x597a900
          flags=0x00000300 fd=31 fd.state=10122 updt=0 fd.tmask=0x1
      filters={0x6e49f30="cache store filter", 0x6e67ad0="compression filter"}
      req=0x6dc2828 (f=0x21840000 an=0x48000 tofwd=0 total=224)
          an_exp=<NEVER> buf=0x6dc2830 data=(nil) o=0 p=0 i=0 size=0
          htx=0x104d2c0 flags=0x0 size=0 data=0 used=0 wrap=NO extra=0
      res=0x6dc2870 (f=0xa0040000 an=0x24000000 tofwd=0 total=309982)
          an_exp=<NEVER> buf=0x6dc2878 data=0x6dceef0 o=16333 p=16333 i=16435 size=32768
          htx=0x6dceef0 flags=0x0 size=32720 data=16333 used=1 wrap=NO extra=0
      -----------------------------------
      strm.flg       0x100c4a  SF_SRV_REUSED SF_HTX SF_REDIRECTABLE SF_CURR_SESS SF_BE_ASSIGNED SF_ASSIGNED
      task.state            0  0
      txn.meth              1  GET
      txn.flg         0x43000  TX_NOT_FIRST TX_CACHE_COOK TX_CACHEABLE
      txn.req.flg        0x4c  HTTP_MSGF_BODYLESS HTTP_MSGF_VER_11 HTTP_MSGF_XFER_LEN
      txn.rsp.flg        0x2e  HTTP_MSGF_COMPRESSING HTTP_MSGF_VER_11 HTTP_MSGF_XFER_LEN HTTP_MSGF_TE_CHNK
      f.sc.flg         0x2482  SC_FL_SND_EXP_MORE SC_FL_RCV_ONCE SC_FL_WONT_READ SC_FL_EOI
      f.sc.sd.flg  0x40405001  SE_FL_HAVE_NO_DATA SE_FL_MAY_FASTFWD_CONS SE_FL_EOI SE_FL_NOT_FIRST SE_FL_T_MUX
      f.h2s.flg        0x7001  H2_SF_HEADERS_RCVD H2_SF_OUTGOING_DATA H2_SF_HEADERS_SENT H2_SF_ES_RCVD
      f.h2s.sd.flg 0x40405001  SE_FL_HAVE_NO_DATA SE_FL_MAY_FASTFWD_CONS SE_FL_EOI SE_FL_NOT_FIRST SE_FL_T_MUX
      f.h2c.flg     0x2000e00  H2_CF_MBUF_HAS_DATA H2_CF_DEM_IN_PROGRESS H2_CF_DEM_SHORT_READ H2_CF_WAIT_INLIST
      f.co.flg     0x80000300  CO_FL_XPRT_TRACKED CO_FL_XPRT_READY CO_FL_CTRL_READY
      f.co.fd.st        0x121  FD_POLL_IN FD_EV_READY_W FD_EV_ACTIVE_R
      b.sc.flg         0x1211  SC_FL_SND_NEVERWAIT SC_FL_NEED_ROOM SC_FL_NOHALF SC_FL_ISBACK
      b.sc.sd.flg  0x106c0001  SE_FL_WAIT_DATA SE_FL_MAY_FASTFWD_CONS SE_FL_MAY_FASTFWD_PROD SE_FL_WANT_ROOM SE_FL_RCV_MORE SE_FL_T_MUX
      b.h1s.sd.flg 0x106c0001  SE_FL_WAIT_DATA SE_FL_MAY_FASTFWD_CONS SE_FL_MAY_FASTFWD_PROD SE_FL_WANT_ROOM SE_FL_RCV_MORE SE_FL_T_MUX
      b.h1s.flg       0x14094  H1S_F_HAVE_CLEN H1S_F_HAVE_O_CONN H1S_F_NOT_FIRST H1S_F_WANT_KAL H1S_F_RX_CONGESTED
      b.h1c.flg    0x80000020  H1C_F_IS_BACK H1C_F_IN_FULL
      b.co.flg          0x300  CO_FL_XPRT_READY CO_FL_CTRL_READY
      b.co.fd.st       0x278a  FD_POLL_OUT FD_POLL_PRI FD_POLL_IN FD_EV_ERR_RW FD_EV_READY_R 0x2008
      req.flg      0x21840000  CF_FLT_ANALYZE CF_DONT_READ CF_AUTO_CONNECT CF_WROTE_DATA
      req.ana         0x48000  AN_REQ_FLT_END AN_REQ_HTTP_XFER_BODY
      req.htx.flg           0  0
      res.flg      0xa0040000  CF_ISRESP CF_FLT_ANALYZE CF_WROTE_DATA
      res.ana      0x24000000  AN_RES_FLT_END AN_RES_HTTP_XFER_BODY
      res.htx.flg           0  0
      -----------------------------------

  - second example of stuck connection after properly checking for WAIT_INLIST
    as well:

    0x73438d0: [23/Oct/2024:18:46:57.235709] id=3963 proto=tcpv4
      flags=0x100c4a, conn_retries=0, conn_exp=<NEVER> conn_et=0x000 srv_conn=0x5dd3f50, pend_pos=(nil) waiting=0 epoch=0x13
      p_stc=25 p_req=29 p_res=29 p_prp=29
      frontend=public (id=2 mode=http), listener=SSL (id=5)
      backend=gitweb-haproxy (id=6 mode=http)
      task=0x72a13e0 (state=0x00 nice=0 calls=24 rate=0 exp=7s tid=0(1/0) age=53s)
      txn=0x7287260 flags=0x43000 meth=1 status=200 req.st=MSG_DONE rsp.st=MSG_DATA req.f=0x4c rsp.f=0x2e
      scf=0x729e520 flags=0x00042082 ioto=1m state=EST endp=CONN,0x737ffd0,0x4040d001 sub=2 rex=<NEVER> wex=46s rto=46s wto=46s
        iobuf.flags=0x00000000 .pipe=0 .buf=0@(nil)+0/0
          h2s=0x737ffd0 h2s.id=57 .st=HCR .flg=0x7001 .rxwin=32712 .rxbuf.c=0 .t=0@(nil)+0/0 .h=0@(nil)+0/0
           .sc=0x729e520(.flg=0x00042082 .app=0x73438d0) .sd=0x72afd50(.flg=0x4040d001)
           .subs=0x729e538(ev=2 tl=0x72af760 tl.calls=10 tl.ctx=0x729e520 tl.fct=sc_conn_io_cb)
           h2c=0x72555a0 h2c.st0=FRH .err=0 .maxid=77 .lastid=-1 .flg=0x60e00 .nbst=1 .nbsc=1 .nbrcv=0 .glitches=0
           .fctl_cnt=0 .send_cnt=1 .tree_cnt=1 .orph_cnt=0 .sub=0 .dsi=77 .dbuf=0@(nil)+0/0
           .mbuf=[2..2|32],h=[0@(nil)+0/0],t=[0@(nil)+0/0] .task=0x725e660 .exp=<NEVER>
          co0=0x7378e00 ctrl=tcpv4 xprt=SSL mux=H2 data=STRM target=LISTENER:0x2f24800
          flags=0x80040300 fd=23 fd.state=1122 updt=0 fd.tmask=0x1
      scb=0x2ee74c0 flags=0x00001211 ioto=1m state=EST endp=CONN,0x7287190,0x106c0001 sub=0 rex=<NEVER> wex=<NEVER> rto=46s wto=<NEVER>
        iobuf.flags=0x00000000 .pipe=0 .buf=0@(nil)+0/0
          h1s=0x7287190 h1s.flg=0x14094 .sd.flg=0x106c0001 .req.state=MSG_DONE .res.state=MSG_DATA
           .meth=GET status=200 .sd.flg=0x106c0001 .sc.flg=0x00001211 .sc.app=0x73438d0 .subs=(nil)
           h1c=0x7373920 h1c.flg=0x80000020 .sub=0 .ibuf=32704@0x7272700+318/32768 .obuf=0@(nil)+0/0 .task=0x729e700 .exp=<NEVER>
          co1=0x72f5290 ctrl=tcpv4 xprt=RAW mux=H1 data=STRM target=SERVER:0x5dd3f50
          flags=0x00000300 fd=19 fd.state=10122 updt=0 fd.tmask=0x1
      filters={0x728f1f0="cache store filter" [3], 0x728fea0="compression filter" [28]}
      req=0x73438f8 (f=0x21840000 an=0x48000 tofwd=0 total=224)
          an_exp=<NEVER> buf=0x7343900 data=(nil) o=0 p=0 i=0 size=0
          htx=0x105f440 flags=0x0 size=0 data=0 used=0 wrap=NO extra=0
      res=0x7343940 (f=0xa0040000 an=0x24000000 tofwd=0 total=359574)
          an_exp=<NEVER> buf=0x7343948 data=0x72b1b30 o=16333 p=16333 i=16435 size=32768
          htx=0x72b1b30 flags=0x8 size=32720 data=16333 used=1 wrap=NO extra=0
      -----------------------------------
      strm.flg       0x100c4a  SF_SRV_REUSED SF_HTX SF_REDIRECTABLE SF_CURR_SESS SF_BE_ASSIGNED SF_ASSIGNED
      task.state            0  0
      txn.meth              1  GET
      txn.flg         0x43000  TX_NOT_FIRST TX_CACHE_COOK TX_CACHEABLE
      txn.req.flg        0x4c  HTTP_MSGF_BODYLESS HTTP_MSGF_VER_11 HTTP_MSGF_XFER_LEN
      txn.rsp.flg        0x2e  HTTP_MSGF_COMPRESSING HTTP_MSGF_VER_11 HTTP_MSGF_XFER_LEN HTTP_MSGF_TE_CHNK
      f.sc.flg        0x42082  SC_FL_EOS SC_FL_SND_EXP_MORE SC_FL_WONT_READ SC_FL_EOI
      f.sc.sd.flg  0x4040d001  SE_FL_HAVE_NO_DATA SE_FL_MAY_FASTFWD_CONS SE_FL_EOS SE_FL_EOI SE_FL_NOT_FIRST SE_FL_T_MUX
      f.h2s.flg        0x7001  H2_SF_HEADERS_RCVD H2_SF_OUTGOING_DATA H2_SF_HEADERS_SENT H2_SF_ES_RCVD
      f.h2s.sd.flg 0x4040d001  SE_FL_HAVE_NO_DATA SE_FL_MAY_FASTFWD_CONS SE_FL_EOS SE_FL_EOI SE_FL_NOT_FIRST SE_FL_T_MUX
      f.h2c.flg       0x60e00  H2_CF_END_REACHED H2_CF_RCVD_SHUT H2_CF_MBUF_HAS_DATA H2_CF_DEM_IN_PROGRESS H2_CF_DEM_SHORT_READ
      f.co.flg     0x80040300  CO_FL_XPRT_TRACKED CO_FL_SOCK_RD_SH CO_FL_XPRT_READY CO_FL_CTRL_READY
      f.co.fd.st       0x1122  FD_POLL_HUP FD_POLL_IN FD_EV_READY_W FD_EV_READY_R
      b.sc.flg         0x1211  SC_FL_SND_NEVERWAIT SC_FL_NEED_ROOM SC_FL_NOHALF SC_FL_ISBACK
      b.sc.sd.flg  0x106c0001  SE_FL_WAIT_DATA SE_FL_MAY_FASTFWD_CONS SE_FL_MAY_FASTFWD_PROD SE_FL_WANT_ROOM SE_FL_RCV_MORE SE_FL_T_MUX
This commit is contained in:
Willy Tarreau 2024-10-23 19:08:55 +02:00
parent a1d0e58b06
commit 1eb31d30fe
1 changed files with 2 additions and 5 deletions
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7
src/mux_h2.c
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@ -4607,10 +4607,7 @@ static int h2_recv(struct h2c *h2c)
}
/* Try to send data if possible.
* The function returns non-zero if some state changes require to call the
* tasklet handler to deal with changes, otherwise zero. Reasons for a wakeup
* are non-zero data sent and ability to demux (indicating a previous blocking)
* or report of a an error.
* The function returns 1 if data have been sent, otherwise zero.
*/
static int h2_send(struct h2c *h2c)
{
@ -4749,7 +4746,7 @@ static int h2_send(struct h2c *h2c)
}
TRACE_DEVEL("leaving with some data left to send", H2_EV_H2C_SEND, h2c->conn);
end:
return (sent && h2_may_demux(h2c)) || (h2c->flags & (H2_CF_ERR_PENDING|H2_CF_ERROR));
return sent || (h2c->flags & (H2_CF_ERR_PENDING|H2_CF_ERROR));
}
/* this is the tasklet referenced in h2c->wait_event.tasklet */