Commit f22f812d authored Sep 12, 2019 by Miklos Szeredi

fuse: fix request limit



The size of struct fuse_req was reduced from 392B to 144B on a non-debug
config, thus the sanitize_global_limit() helper was setting a larger
default limit.  This doesn't really reflect reduction in the memory used by
requests, since the fields removed from fuse_req were added to fuse_args
derived structs; e.g. sizeof(struct fuse_writepages_args) is 248B, thus
resulting in slightly more memory being used for writepage requests
overalll (due to using 256B slabs).

Make the calculatation ignore the size of fuse_req and use the old 392B
value.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

parent 05ea48cc

fs/fuse/inode.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -826,9 +826,12 @@ static const struct super_operations fuse_super_operations = {

		static void sanitize_global_limit(unsigned *limit)
		{
		/*
		* The default maximum number of async requests is calculated to consume
		* 1/2^13 of the total memory, assuming 392 bytes per request.
		*/
		if (*limit == 0)
		*limit = ((totalram_pages() << PAGE_SHIFT) >> 13) /
		sizeof(struct fuse_req);
		*limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;

		if (*limit >= 1 << 16)
		*limit = (1 << 16) - 1;

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