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posix-timers: Cleanup comments about timer ID tracking

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Describe the hash table properly and remove the IDR leftover comments.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230425183313.038444551@linutronix.de
This commit is contained in:
Thomas Gleixner 2023-04-25 20:49:01 +02:00
parent 7d99090266
commit 8d44b958a1
1 changed files with 9 additions and 21 deletions
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30
kernel/time/posix-timers.c
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@ -35,20 +35,17 @@
#include "timekeeping.h"
#include "posix-timers.h"
/*
* Management arrays for POSIX timers. Timers are now kept in static hash table
* with 512 entries.
* Timer ids are allocated by local routine, which selects proper hash head by
* key, constructed from current->signal address and per signal struct counter.
* This keeps timer ids unique per process, but now they can intersect between
* processes.
*/
/*
* Lets keep our timers in a slab cache :-)
*/
static struct kmem_cache *posix_timers_cache;
/*
* Timers are managed in a hash table for lockless lookup. The hash key is
* constructed from current::signal and the timer ID and the timer is
* matched against current::signal and the timer ID when walking the hash
* bucket list.
*
* This allows checkpoint/restore to reconstruct the exact timer IDs for
* a process.
*/
static DEFINE_HASHTABLE(posix_timers_hashtable, 9);
static DEFINE_SPINLOCK(hash_lock);
@ -65,15 +62,6 @@ static const struct k_clock clock_realtime, clock_monotonic;
#error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
#endif
/*
* The timer ID is turned into a timer address by idr_find().
* Verifying a valid ID consists of:
*
* a) checking that idr_find() returns other than -1.
* b) checking that the timer id matches the one in the timer itself.
* c) that the timer owner is in the callers thread group.
*/
/*
* CLOCKs: The POSIX standard calls for a couple of clocks and allows us
* to implement others. This structure defines the various