Chris Webb 872cd437e7 bcachefs-tools: Avoid glibc-specific mallinfo() in shrinker ... Before 326d7c1, the shrinker used freeram and totalram from a struct sysinfo (constructed from /proc/meminfo) to target 25% free physical memory. As well as the slowness of repeatedly reading /proc/meminfo, this was a problem as freeram rises when the system starts to swap. We don't want swapping to reduce our estimate of memory pressure. To work around this, in 326d7c1 the shrinker started to use the total allocated heap from a glibc-specific interface mallinfo2(), aiming to shrink such that our heap is less than 80% of physical memory, unless overall free memory is less than 6% so that becomes the determining factor. Unfortunately, a sign error in the calculation means this heuristic never worked. It would shrink aggressively when the process was small, and not at all when the process grew beyond 80% of physical RAM. Only the fallback test ensuring the free physical RAM doesn't fall below 6% would actually kick in under memory pressure. It also breaks portability to anything other than recent glibc. Later, in 2440469 the mallinfo2() was replaced with the older mallinfo() to improve compatibility with older glibc. This is even more problematic: it's still not portable but also struct mallinfo has (signed) int fields which overflow for large processes on 32-bit machines with a 3G/1G split. Rather than trying to use libc-specific debug interfaces and our own heap to inform the shrinker, use the information about free and total swap we already have from sysinfo(2) to explicitly compensate for swapping in our estimate of free physical memory. Target free memory of 6% of physical RAM adjusted for zero swap use when calculating the pressure on the shrinker, based on the effective behaviour of 326d7c1 in practice given the sign error. As well as fixing portability to non-glibc systems, this loosens the assumption that we are the only process using significant memory when setting the shrinker target. It wouldn't be unreasonable to run two fsck jobs against independent devices on a large RAM machine and want to balance physical RAM between them. Signed-off-by: Chris Webb <chris@arachsys.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>		2023-12-09 23:28:01 -05:00
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crypto
atomic64.c
bio.c	Update bcachefs sources to 84f132d569 bcachefs: fsck: Break walk_inode() up into multiple functions	2023-06-27 19:38:18 -04:00
blkdev.c	Handle -EAGAIN from io_submit()	2023-09-29 01:27:59 -04:00
closure.c	Update bcachefs sources to 783085c3cc44 kbuild: Allow gcov to be enabled on the command line	2023-11-22 16:55:06 -05:00
crc64.c
crc64table.h
fs.c	Update bcachefs sources to 84f132d569 bcachefs: fsck: Break walk_inode() up into multiple functions	2023-06-27 19:38:18 -04:00
generic-radix-tree.c	Update bcachefs sources to 6ddf061e68 bcachefs: Use a genradix for reading journal entries	2022-04-08 19:26:30 -04:00
int_sqrt.c	Update bcachefs sources to 3e93567c51 bcachefs: Switch to local_clock() for fastpath time source	2022-10-15 01:04:30 -04:00
kstrtox.c
kstrtox.h
kthread.c	Run shrinkers when pthread_create fails	2023-07-20 21:28:03 -04:00
llist.c	Update llist code	2019-08-28 11:35:00 -04:00
mempool.c	Add a real mempool implementation	2021-04-24 01:36:43 -04:00
preempt.c	Fix building on musl	2020-05-05 10:29:31 +01:00
ratelimit.c	Fix printk_ratelimited()	2022-06-22 22:05:39 -04:00
rhashtable.c	Update bcachefs sources to 18686af684 bcachefs: Inode backpointers	2021-03-29 00:22:38 -04:00
sched.c	Don't use mlockall()	2021-01-12 16:36:45 -05:00
semaphore.c	Update bcachefs sources to 4837f82ee1 bcachefs: Use cached iterators for alloc btree	2020-06-15 16:27:19 -04:00
seq_buf.c	Update bcachefs sources to ea93c26e98 fixup! bcachefs: We can handle missing btree roots for all alloc btrees	2023-02-09 18:36:24 -05:00
shrinker.c	bcachefs-tools: Avoid glibc-specific mallinfo() in shrinker	2023-12-09 23:28:01 -05:00
siphash.c	Update bcachefs sources to ba398d2906 bcachefs: Fix reflink repair code	2022-02-13 04:08:33 -05:00
string_helpers.c	Update bcachefs sources to ea93c26e98 fixup! bcachefs: We can handle missing btree roots for all alloc btrees	2023-02-09 18:36:24 -05:00
string.c	Update bcachefs sources to cd779e0cc5 bcachefs: Skip inode unpack/pack in bch2_extent_update()	2022-10-22 14:41:54 -04:00
timer.c	Heap code fix	2022-03-28 12:39:12 -04:00
wait.c	Update bcachefs sources to 8d3fc97ca3 bcachefs: Fixes for building in userspace	2022-11-13 20:07:22 -05:00
workqueue.c	Update bcachefs sources to c9b4a210f9 fixup! bcachefs: Fixes for going RO	2020-06-03 19:56:33 -04:00
xxhash.c	Update bcachefs sources to dbee44d5ab bcachefs: add bcachefs xxhash support	2021-07-07 20:30:53 -04:00
zstd_compress_module.c	Update bcachefs sources to e48731a188 bcachefs: Fix BTREE_TRIGGER_WANTS_OLD_AND_NEW	2022-03-13 19:20:59 -04:00
zstd_decompress_module.c	Update bcachefs sources to e48731a188 bcachefs: Fix BTREE_TRIGGER_WANTS_OLD_AND_NEW	2022-03-13 19:20:59 -04:00