mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-01-30 10:31:54 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

MDEV-24670 memory pressure - eventfd rather than pipe

Browse source 
Eventfds have a simplier interface and are one file
descriptor rather than two.

Reuse the patten of the accepting socket connections
by testing for abort after a poll returns. This way
the same event descriptor can be used for Quit
and debugging trigger.

Also correct the registration of mem pressure file
descriptors.
This commit is contained in:
Daniel Black 2023-11-23 13:03:01 +11:00
parent f2bd662f6c
commit a48c1b89c8
1 changed files with 27 additions and 32 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

59
storage/innobase/buf/buf0buf.cc
View file

@ -744,6 +744,7 @@ bool buf_page_is_corrupted(bool check_lsn, const byte *read_buf,
#ifdef __linux__
#include <poll.h>
#include <sys/eventfd.h>
#include <fstream>
/** Memory Pressure
@ -752,14 +753,16 @@ based off https://www.kernel.org/doc/html/latest/accounting/psi.html#pressure-in
and https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html#memory */
class mem_pressure
{
/* triggers + pipe */
/* triggers + eventfd */
struct pollfd m_fds[3];
nfds_t m_num_fds;
int m_pipe[2]= {-1, -1};
int m_event_fd= -1;
Atomic_relaxed<bool> m_abort= false;
std::thread m_thd;
/* mem pressure garbarge collection resticted to interval */
/* mem pressure garbage collection restricted to interval */
static constexpr ulonglong max_interval_us= 60*1000000;
public:
mem_pressure() : m_num_fds(0) {}
@ -796,7 +799,7 @@ public:
shutdown();
return false;
}
my_register_filename(m_pipe[0], memcgroup.c_str(), FILE_BY_OPEN, 0, MYF(0));
my_register_filename(m_fds[m_num_fds].fd, memcgroup.c_str(), FILE_BY_OPEN, 0, MYF(0));
ssize_t slen= strlen(*trig);
if (write(m_fds[m_num_fds].fd, *trig, slen) < slen)
{
@ -810,15 +813,14 @@ public:
if (m_num_fds < 1)
return false;
if (pipe2(m_pipe, O_CLOEXEC | O_DIRECT))
if ((m_event_fd= eventfd(0, EFD_CLOEXEC|EFD_NONBLOCK)) == -1)
{
sql_print_warning("InnoDB: No memory pressure - can't create pipe");
sql_print_warning("InnoDB: No memory pressure - can't create eventfd");
shutdown();
return false;
}
my_register_filename(m_pipe[0], "mem_pressure_read", FILE_BY_DUP, 0, MYF(0));
my_register_filename(m_pipe[1], "mem_pressure_write", FILE_BY_DUP, 0, MYF(0));
m_fds[m_num_fds].fd= m_pipe[0];
my_register_filename(m_event_fd, "mem_pressure_eventfd", FILE_BY_DUP, 0, MYF(0));
m_fds[m_num_fds].fd= m_event_fd;
m_fds[m_num_fds].events= POLLIN;
m_num_fds++;
m_thd= std::thread(pressure_routine, this);
@ -827,18 +829,13 @@ public:
void shutdown()
{
/* m_event_fd is in this list */
while (m_num_fds)
{
m_num_fds--;
my_close(m_fds[m_num_fds].fd, MYF(MY_WME));
m_fds[m_num_fds].fd= -1;
}
/* note m_pipe[0] closed in above loop */
if (m_pipe[1] >= 0)
{
my_close(m_pipe[1], MYF(MY_WME));
m_pipe[1]= -1;
}
}
static void pressure_routine(mem_pressure *m);
@ -846,8 +843,8 @@ public:
#ifdef UNIV_DEBUG
void trigger_collection()
{
const char c= 'G';
if (m_pipe[1] >=0 && write(m_pipe[1], &c, 1) < 1)
uint64_t u= 1;
if (m_event_fd >=0 && write(m_event_fd, &u, sizeof(uint64_t)) != sizeof(uint64_t))
sql_print_information("InnoDB: (Debug) Failed to trigger memory pressure");
else /* assumed failed to meet intialization criteria, so trigger directy */
buf_pool.garbage_collect();
@ -856,8 +853,9 @@ public:
void quit()
{
const char c= 'Q';
if (m_num_fds && write(m_pipe[1], &c, 1) < 1)
uint64_t u= 1;
m_abort= true;
if (write(m_event_fd, &u, sizeof(uint64_t)) != sizeof(uint64_t))
sql_print_warning("InnoDB: Failed to write memory pressure quit message");
}
@ -896,7 +894,7 @@ void mem_pressure::pressure_routine(mem_pressure *m)
}
ulonglong last= microsecond_interval_timer() - max_interval_us;
while (1)
while (!m->m_abort)
{
if (poll(&m->m_fds[0], m->m_num_fds, -1) < 0)
{
@ -909,6 +907,9 @@ void mem_pressure::pressure_routine(mem_pressure *m)
break;
}
}
if (!m->m_abort)
break;
for (pollfd &p : st_::span<pollfd>(m->m_fds, m->m_num_fds))
{
if (p.revents & POLLPRI)
@ -921,23 +922,17 @@ void mem_pressure::pressure_routine(mem_pressure *m)
}
}
#ifdef UNIV_DEBUG
if (p.revents & POLLIN)
{
char c= '\0';
/* signal to quit */
if (read(p.fd, &c, 1) >=0)
switch (c) {
case 'Q':
goto shutdown;
#ifdef UNIV_DEBUG
case 'G':
buf_pool.garbage_collect();
#endif
}
uint64_t u;
/* we haven't aborted, so this must be a debug trigger */
if (read(p.fd, &u, sizeof(u)) >=0)
buf_pool.garbage_collect();
}
#endif
}
}
shutdown:
m->shutdown();
my_thread_end();