search for: lru_set_recently_accessed

...tdbool.h> + +/* Initialize LRU. */ +extern void lru_init (void); + +/* Free the LRU. */ +extern void lru_free (void); + +/* Notify LRU that the virtual size has changed. */ +extern int lru_set_size (uint64_t new_size); + +/* Mark a block as recently accessed in the LRU structure. */ +extern void lru_set_recently_accessed (uint64_t blknum); + +/* Check if a block has been recently accessed. */ +extern bool lru_has_been_recently_accessed (uint64_t blknum); + +#endif /* NBDKIT_LRU_H */ diff --git a/filters/cache/blk.c b/filters/cache/blk.c index 4000276..b256446 100644 --- a/filters/cache/blk.c +++ b/filters/cache/blk...

...tdbool.h> + +/* Initialize LRU. */ +extern void lru_init (void); + +/* Free the LRU. */ +extern void lru_free (void); + +/* Notify LRU that the virtual size has changed. */ +extern int lru_set_size (uint64_t new_size); + +/* Mark a block as recently accessed in the LRU structure. */ +extern void lru_set_recently_accessed (uint64_t blknum); + +/* Check if a block has been recently accessed. */ +extern bool lru_has_been_recently_accessed (uint64_t blknum); + +#endif /* NBDKIT_LRU_H */ diff --git a/filters/cache/blk.c b/filters/cache/blk.c index 4000276..b256446 100644 --- a/filters/cache/blk.c +++ b/filters/cache/blk...

Patch 1 is the same as last time, except for a minor comment fix. Patch 2 should address everything that Eric mentioned in his review, and has been retested. Rich.

v3 was broken by a bad rebase, so let's forget about that one. Compared to v2: - Patch 1 is the same except for a minor comment change. - Patch 2 splits the reclaim code into a separate file (filters/cache/reclaim.c) - Addressed Eric's comments from his review of v2. - Retested on Linux and FreeBSD.

These are essentially identical to what was previously posted as patches 6/9 through 9/9 here: https://www.redhat.com/archives/libguestfs/2018-December/msg00145.html except that it has been rebased onto the current git master and retested thoroughly. Rich.

v4: https://www.redhat.com/archives/libguestfs/2019-January/msg00032.html v5: - Now we set the block size at run time. I'd like to say that I was able to test this change, but unfortunately I couldn't find any easy way to create a filesystem on x86-64 with a block size > 4K. Ext4 doesn't support it at all, and XFS doesn't support block size > page size (and I

...s this is only a heuristic we choose > + * to keep the implementation simple and memory usage low instead. Seems reasonable enough. > + */ > +static struct bitmap bm[2]; > +static unsigned c0 = 0, c1 = 0; Static variables already start life zero-initialized. > + > +void > +lru_set_recently_accessed (uint64_t blknum) > +{ > + /* If the block is already set in the first bitmap, don't need to do > + * anything. > + */ > + if (bitmap_get_blk (&bm[0], blknum, false)) > + return; And this implements the latter (the most recent N blocks accessed, not the most rece...

This patch series enhances the cache filter in a few ways, primarily adding a "cache-on-read" feature (similar to qemu's copyonread); and adding the ability to limit the cache size and the antecedent of that which is having a method to reclaim cache blocks. As the cache is stored as a sparse temporary file, reclaiming cache blocks simply means punching holes in the temporary file.

Since v1: - rework .can_cache to be tri-state, with default of no advertisement (ripple effect through other patches) - add a lot more patches in order to round out filter support And in the meantime, Rich pushed NBD_CMD_CACHE support into libnbd, so in theory we now have a way to test cache commands through the entire stack. Eric Blake (24): server: Internal hooks for implementing