Citation Envoyé par Jipété Voir le message
Elle sort d'où, la valeur 50 ? Du chapeau ? Chez moi j'ai 100 dans /proc/sys/vm/vfs_cache_pressure.
C'est une valeur conseillée par la majorité des articles sur la toile - sûrement empiriquement après moult tests - voir également le type de disque dur (HDD ou SSD), la taille de la RAM, etc.

vfs_cache_pressure
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This percentage value controls the tendency of the kernel to reclaim
the memory which is used for caching of directory and inode objects.

At the default value of vfs_cache_pressure=100 the kernel will attempt to
reclaim dentries and inodes at a "fair" rate with respect to pagecache and
swapcache reclaim. Decreasing vfs_cache_pressure causes the kernel to prefer
to retain dentry and inode caches. When vfs_cache_pressure=0, the kernel will
never reclaim dentries and inodes due to memory pressure and this can easily
lead to out-of-memory conditions. Increasing vfs_cache_pressure beyond 100
causes the kernel to prefer to reclaim dentries and inodes.

Increasing vfs_cache_pressure significantly beyond 100 may have negative
performance impact. Reclaim code needs to take various locks to find freeable
directory and inode objects. With vfs_cache_pressure=1000, it will look for
ten times more freeable objects than there are.
Source : https://www.kernel.org/doc/Documentation/sysctl/vm.txt